D03C Hardwood Flooring

D03C - MATERIAL GUIDES - HARDWOOD FLOORING

D03C-1 Hardwood
D03C-2 Solid hardwood flooring
D03C-3 Engineered hardwood flooring
D03C-4 Laminate flooring
D03C-5 Hardwood sports flooring
D03C-6 Specialty hardwood flooring
D03C-7 Hardwood flooring edges
D03C-8 Hardwood flooring textures and patterns
D03C-9 Hardwood flooring molding, trims, and accessories
D03C-10 Hardwood stairs
D03C-11 Hardwood flooring underlayments
D03C-12 Hardwood flooring adhesives
D03C-13 Hardwood flooring fastenings
D03C-14 Special installation systems
D03C-15 Special installation requirements
D03C-16 Hardwood finishing

Preface:
This study guide covers solid strip, plank, and parquet hardwood and engineered (or laminated) flooring and related materials. The information given is a guide only and cannot fully cover all aspects of such flooring and its installation. Specifiers and/or persons selecting such products should verify all facts relative to the particular project requirements.

This study guide does not cover laminate wood flooring which is included under Part E03C - Material Guide (Laminate Flooring).

To fully understand how to choose hardwood flooring for a residential, commercial, or an institutional installation, a thorough knowledge of hardwood species, grades, finishes, and related materials as well as types of installation systems and methods is essential. The following information is offered as a guide only and will hopefully assist all those who have to deal with this type of flooring (designers, suppliers, installers, Owners, etc.) in becoming more aware of the issues concerned in choosing an appropriate hardwood type, finish, and installation method required to suit a project's requirements.

1 • HARDWOOD

.01 What is Hardwood:

Hardwood is a description applied to woods from deciduous broad-leafed trees (Angiosperms) that produce a fruit or nut and generally go dormant in the winter in contrast to that from evergreen or conifer (cone bearing) trees or softwoods.

The term "hardwood" has no reference to the actual hardness of the wood or hardwood flooring as both open-grain and close-grain hardwoods and some softwoods are used in hardwood flooring. There are also both hardwoods and softwoods that aren't recommended for "hardwood" flooring because they are not hard enough to withstand heavy wear and tear.

Hardwoods suitable for use in flooring include such domestic (North American) species as Oak, Ash, Cherry, Maple, and Poplar as well as such imported (tropical) species as Mahogany, Rosewood, Teak, and Wenge.

Heading the list of the most suitable and widely used hard, open-grain wood is Oak. Northern Walnut, Pecan, Ash, Elm, and Chestnut are also open-grain hardwoods. Among close-grain hardwoods are Maple, Birch, and Beech.

.02 Hardwood Species:

More than 50 species of wood are used for hardwood flooring. These come from both domestic (North American) sources and from many foreign sources (Central and South America, Europe, Africa, Asia, Australia, and the Far East) and span the spectrum of colour options, hardness, and price ranges.

For an explanation of species refer to Part D03D - Material Guide - Species .

.03 Hardwood Grading:

Material for hardwood flooring is manufactured from hardwood or softwood lumber that has been kiln-dried to a specific moisture content level, air-cooled, cut into appropriate sizes, and then accurately milled into strip or plank form with required profiles (e.g. tongue and groove edges, and square, eased, or bevelled top faces).

Once such milling is complete the material is carefully graded based on a number of parameters or grading rules that have been established by various industry associations that were established by hardwood manufacturers. Some of these associations are:
- Canadian Lumber Association (CLA)
- National Wood Flooring Association (NWFA).
- Maple Flooring Manufacturers Association (MFMA).
- Southern Pine Inspection Bureau (SPIB).

These associations have established minimum standards or rules in regard to the surface characteristics, required lengths, milling tolerances, and moisture content of milled wood within a species and also groups the material having similar qualities into like groups or grades. In addition to creating grades, the associations also provide an impartial service to settle grading disputes and perform grading inspections. This brings a degree of consistency in products from different manufacturers who choose to adhere to these established grading rules.

Manufacturers who do not belong to these associations or adhere to the association grading rules may develop classifications and "proprietary" grades for their own flooring materials.

For specific species grading requirements, refer to D03E - Material Guide - Grades.

Most manufacturers of engineered and pre-finished flooring follow their own grading rules. At present, no association standards exist for engineered wood floors.

2 • SOLID HARDWOOD FLOORING

.01 Solid hardwood flooring is milled from hardwood or softwood into strip or plank form, or cut into fillet strips and assembled into tile form (parquet).

Solid hardwood strip and plank flooring is produced in various thicknesses and widths in random lengths from 300 mm (12") to 2135 mm (84") although longer lengths may be available in some species and grades. Solid parquet fillets are cut to appropriate sizes to suit tile requirements. This type of solid flooring material can be site or pre-finished and because of its thickness can be refinished or recoated several times during its lifetime.

Note in regard to Availability: In all cases the thicknesses, widths, lengths, edge and top face details for both solid and engineered strip, plank, and parquet flooring as noted herein must be verified with the applicable grading association for the species and grade selected.

Note in regard to Installation: "Solid" hardwood flooring is sensitive to moisture and the installation of it is not recommended on concrete substrate surfaces on or below grade levels.

.02 Solid Strip Flooring: These are solid hardwood strips (material less than 75 mm (3") in nominal width) that are designed to be installed in parallel rows. Typically they are all of the same width but may also be combined with planks.

Thicknesses: Varies with species and edge profile - 8 mm (5/16"), 9 mm (11/32"), 10 mm (3/8"), 13 mm (1/2"), 19 mm (3/4"), 20 mm (25/32"), and 26 mm (33/32").

Widths: Varies with species and thickness - 38 mm (1-1/2"), 50 mm (2"), 57 mm (2-1/4"), and 83 mm (3 1/4").

Lengths: Random (Refer to grading rules).

Side Edges: Tongue and groove and square.

Top Face Edges: Square, eased, and bevelled (verify with manufacturer).

Species: Available in Oak (Red and White) Beech, Birch, Hard Maple, and Pecan.

Grading: In accordance with CLA, NOFMA, MFMA, SPIB, or other official rules.

Finish: Factory pre-finished or unfinished for sanding and finishing on site.

Installation: May be mechanically fastened (concealed / side nailed in tongue or face nailed) or glued down (but either method not directly to concrete) over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.03 Solid Plank Flooring: These are solid hardwood planks in nominal widths from 75 mm (3") to 200 mm (8") that are designed to be installed in parallel rows. Plank flooring can be combined with strip flooring and/or in alternate widths and/or random lengths.

Thicknesses: Varies with species - 19mm (3/4") with 22 mm (7/8") also available from some manufactures.

Widths: Varies with species - 75 mm (3") to 200 mm (8"), although wider widths may be available in some species and grades.

Lengths: Random (refer to grading rules / verify with manufacturer).

Side Edges: Typically tongue and groove.

Top Face: Edges may be square, eased, or bevelled (verify with manufacturer).

Species: Available in Red or White Oak, Beech, Birch, Hard Maple, and Pecan.

Grading: In accordance with CLA, NOFMA, MFMA, SPIB, or other official rules.

Finish: Factory pre-finished or unfinished for sanding and finishing on site.

Installation: Typically mechanically fastened (concealed / side nailed in tongue or face nailed) or may also be glued down (but either method not directly to concrete) over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.04 Solid Parquet Flooring: This type of flooring consists of small wood slats or fillets of solid hardwood assembled in units or "tiles" that may consist of individual squares, or units with slats arranged in various patterns, or with slats of same or contrasting species.

Thicknesses: 8 mm (5/16") and 19 mm (3/4").

Slat Sizes: Varies depending on pattern selected.

Unit or Tile Sizes: varies from 100 mm (4") up to 300 mm (12") square but may vary depending on pattern selected. Multiple tiles (usually four depending on size) with a common paper or mesh backing may also be available. Verify with manufacturer.

Side Edges: Usually square although tongue and groove may be available for some large tiles (verify with manufacturer).

Top Face Edges: Usually square although other edge types (eased or bevelled) may be available (verify with manufacturer).

Species: Available in Oak (Red and White) Maple, Black Walnut, Cherry, Cedar, and Ash. Note - Not all patterns are available in the species listed.

Grading: In accordance with CLA, NOFMA, MFMA, or other official grading rules.

Patterns: Typically square tiles, but also available in other patterns (verify with manufacturer for variety available).

Finish: Factory pre-finished or unfinished for sanding and finishing on site.

Installation: Typically glued down but may also be mechanically fastened (but either method not directly to solid board subfloors) over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.05 Self-Adhesive Solid Parquet Flooring: This type of flooring consists of parquet flooring panels as noted above complete with a self-adhesive (peel and stick) backing. The design authority must verify all requirements (e.g., species, patterns, etc.) and availability of this type of parquet flooring with suppliers before use.

3 • ENGINEERED HARDWOOD FLOORING

.01 Engineered flooring (also referred to as laminated not laminate flooring) consists of a décor or pattern layer of either sawn solid hardwood or a rotary peeled or flat cut slice of           hardwood veneer bonded to a plywood core with plies at right angles to the grain of the top and bottom layer, a core layer of either plywood (with plies at right angles to grain of       top and bottom layer), medium density fibreboard (MDF), or high density fibreboard (HDF), and a bottom balancing layer. This minimum three-layer assembly is adhesive                   bonded together in accordance with manufacturer's requirements using heat and pressure as applicable.

.02 Engineered wood flooring is manufactured in single strips or planks, multiple strip and/or plank panels, and in parquet form using a wide variety of domestic and exotic hardwood       species. This type of flooring is either pre-finished (sawn or veneer slice décor layer types) or unfinished (sawn décor layer only) and may be installed as a floating assembly with       friction fit ("locked" or "clicked") joints, or may be mechanically fastened (i.e., stapled or nailed), or glued to an approved substrate as recommended by the manufacturer.

.03 The types of engineered wood flooring having a thin veneer layer can be screened (lightly sanded) and re-coated but usually cannot be sanded and refinished again once they           become worn. Engineered wood flooring having a thicker layer of hardwood can be screened and recoated or re-sanded and refinished a number of times depending on the               thickness of the top layer. In either case, screening and recoating or sanding and refinishing engineered flooring must be verified with the manufacturer before attempted.

      Note: A thin veneer is one that is less than 1 mm in thickness.

.04 Standards: Engineered flooring is manufactured in both North American and Europe and its fabrication is therefore governed by a variety of standards, including the following:

ANSI/HPVA EF 2012, Standard for Engineered Wood Flooring. This is a joint American National Standards Institute (ANSI) / Hardwood Plywood Manufacturers Association (HPMA) standard. (a North American standard)

EN 13629, Wood flooring - Solid pre-assembled hardwood boards. This is a European Norm standard.
Note: The design authority must determine what requirements and standards are appropriate when comparing engineered flooring from these two sources. If both North American and European engineered flooring is used then the minimum requirements of the one should govern both as long as the requirements are carefully evaluated.

.05 Availability: In all cases, thickness, widths, lengths, edge and top face details for engineered strips, planks, panels, and parquet flooring as noted herein must be verified with           the applicable manufacturer / supplier for the species and grade selected.

.06 Installation: Engineered hardwood flooring may be installed above, on, or below grade BUT verify with specific product manufacturer for installation requirements where                   moisture may be a problem (i.e. on concrete substrate surfaces on or below grade levels).

.07 Engineered Strip and Plank Flooring: These are single or multiple strips or planks assembled in accordance with requirements noted above that are designed to be installed in     parallel rows.

Thicknesses: 8 mm (5/16"), 10 mm (3/8"), and 16 mm (5/8") (verify with manufacturer).

Widths: 75 mm (3") to 178 mm (7") wide (verify with manufacturer).

Lengths: Fixed and random (Refer to grading rules and manufacturer).

Side Edges: Tongue and groove.
Top Face Edges: Eased, bevelled, or square (verify with manufacturer).

Species: Face veneer available in Red and White Oak, Beech, Birch, Hard Maple, Ash, Walnut, and Cherry. Other species are available from some flooring manufacturers.

Grading: In accordance with applicable grading rules for species.

Finish: Factory pre-finished or unfinished for sanding and finishing on site.

Installation: May be loose laid or floated (for engineered flooring with mechanically fastened joints), mechanically fastened (side nailed in tongue or using special "clip" system method) with or without acoustical underlayment or glued down (but any method not directly to concrete) over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association (e.g. NOFMA) and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.08 Engineered Parquet Flooring: This type of flooring consists of small slats or fillets of sawn hardwood as noted herein assembled in units or "tiles" that may consist of individual squares, or units with slats arranged in various patterns, or with slats of same or contrasting species.

Thicknesses: 8 mm (5/16") and 10 mm (3/8").

Slat Sizes: Varies depending on pattern selected.

Unit or Tile Sizes: varies from 100 mm (4") up to 300 mm (12") square but may vary depending on pattern selected. Multiple tiles (usually four depending on size) with a common paper or mesh backing may also be available. Verify with manufacturer.

Side Edges: Square (usually unfinished) or tongue and groove (usually pre-finished) to suit requirements (verify with manufacturer).

Top Face Edges: Usually eased or bevelled (verify with manufacturer).

Species: Available in Red and White Oak. Other species may be available from some manufacturers.

Grading: In accordance with NOFMA official grading rules. Other species (if available) to appropriate grading rules.

Patterns: Typically linear slats but may also be available in other patterns (refer to each manufacturer for variety available).

Finish: Factory pre-finished or unfinished for sanding and finishing on site.

Installation: Typically glued down over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association (e.g. NOFMA) and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.09 Self-Adhesive Engineered Parquet Flooring: This type of flooring consists of engineered parquet flooring as noted above complete with a self-adhesive (peel and stick) backing. The design authority must verify all requirements (e.g., species, patterns, etc.) and availability of this type of parquet flooring with suppliers before use.

4 • LAMINATE FLOORING

.01 This type of flooring should not be confused with engineered or laminated flooring.

.02 Refer to Part E03C - Material Guide for a description of this type of flooring material.

5 • HARDWOOD SPORTS FLOORING

.01 Flooring: This type of flooring consists of solid hardwood strips on a resilient floor system assembly suitable for gymnasiums, auditoriums, indoor tennis, basketball, handball, squash, and racquet ball courts, stages, and dance / ballet studios. The installation may be permanent or portable (i.e., fully removable).

Thickness: 20 mm (25/32") and 25 mm (33/32") although thickness may vary depending on type of system.

Strip Widths: 38 mm (1-1/2"), 45 mm (1-3/4"), 50 mm (2"), 57 mm (2-1/4"), 83 mm (3-1/4") as recommended by manufacturer for type of system selected.

Strip Lengths: Random for strip pattern, or specified length for parquet patterns.

Side Edges: tongue and groove.

Top Face Edges: square.

Species: typically Northern Hard Maple, except other species may be available.

Grading: In accordance with MFMA, CLA, or other appropriate grading rules and manufacturer's requirements.

Finish: Typically unfinished for site sanding, finishing, and application of game markings, except removal floor systems may be pre-finished in panel form complete with game line markings.

Game Markings: Refer to MFMA guidelines or specific sport association for court layout dimensions, lines, and colours and to flooring distributor for type of durable paint compatible with floor finish to use for line work.

Installation: Over an acceptable substrate in accordance with hardwood sports flooring manufacturer's system assembly recommendations and applicable grading association (e.g. MFMA, NOFMA) and NFCA requirements.

Availability: Refer to specific manufacturer / supplier.

.02 Sport Flooring System Assemblies: There are a variety of engineered systems used as part of a hardwood sports flooring installation over a concrete of wood floor substrate. These are intended to suit a variety of activities such as court games (basketball, volleyball, badminton, etc.), aerobics, gymnastics, dancing, as well as assembly purposes such as theatre productions, gymnasiums, auditoriums, convention centres, etc. Such systems are designed to meet specific and measurable performance, safety, and comfort criteria such as shock absorption, ball bounce, vertical and area deflection, surface friction, and rolling loads (as well as other design loads for bleachers, backstops, etc.).

The following should be considered for any sports floor installation:

Shock Absorption: As an athlete impacts a sports surface the impacting force is translated into two resultant forces, one absorbed by the floor, the other returned to the athlete. Hard surfaces such as concrete and asphalt provide little or no force reduction for the athlete upon impact, due to running, jumping or falling. Sports floor systems absorb these impact forces (shock) and are rated by the percentage of force reduction they provide as compared to hard surfaces.

Vertical and Area Deflection: The measurements of both area and vertical deflection are interdependent. The two together form a criterion for determining the total stability of the floor in the total scheme of performance characteristics. This is called deformation control. This characteristic is a measure of the systems ability to provide vertical deflection for athletes performing in close proximity to each other such as in basketball. Vertical deflection deals with vertical displacement of the flooring surface during impact.

Ball Bounce: This measurement of a basketball's response reflecting (rebounding) off a hardwood sports floor system as compared to its response off a hard surface such as concrete is referred to ball bounce. At 100% rebound, the basketball reflects to a height equal to its response off concrete. This may not apply to all sports activities.

Surface Friction: Often called Sliding coefficient or the coefficient of friction, this characteristic is used to measure the floor's ability to control sliding of athletes on its surface. A sports floor system must have a high surface friction with enough to prevent premature and uncontrollable sliding but low enough to permit sliding if an extreme force is exerted on an athlete such as that caused by two athletes colliding together. Surface friction is a direct function of the finish on the surface and carries equal importance in all activities.

Rolling Loads: Due to the potential damage caused by some maintenance machines, game equipment (backstops, etc.), and furniture (chair dollies, bleachers, high lifts, etc.) designing a flooring system to include for such rolling loads is very important. The pressure of rolling loads caused by rolling equipment and furniture as well as additional provisions to protect the floor should be considered.

Note: The Design Authority must contact the hardwood sports flooring manufacturer or supplier for types of systems available to meet the necessary performance requirements.

Some of these "subfloor systems" include:

Panel system comprising two layers of laminated plywood and resilient pads.
Sleeper system comprising softwood sleepers and resilient pads
Sleeper Subfloor System comprising both of the above systems with one or two layers of plywood.

A variety of components are used in the above assemblies. These may include:

.03 Sports Flooring System Components:

Membrane: Refer to "Underlayments" noted below.

Resilient Pads or Cushion: resilient material with type of material and configuration (individual pads or continuous sheet cushion) in accordance with sport flooring manufacturer's system requirements.
and / or
- Sleepers: continuous kiln dried water repellent preservative treated solid wood (e.g. Douglas Fir) or plywood strips in accordance with sport flooring manufacturer's system requirements. These may also be proprietary metal strips configured to accept resilient pads.
- Plywood: Minimum of one layer of 19 mm (3/4") or two layers of 13 mm (1/2") thick x 1200 mm x 2400 mm (48" x 96") exterior grade Douglas Fir plywood. Where two layers are used they shall be nailed together at 45° or 90° angles, unless otherwise required by sports flooring manufacturer.
- System Anchoring Devices: Sport flooring manufacturer's proprietary channels and/or adjustable fastener system.
- Vent-Cove Base: Solid rubber vented cove base designed to permit ventilation of the void space under flooring and to cover perimeter expansion space. This base is usually available in various colours and is supplied by the sports flooring or a resilient flooring manufacturer or supplier. The design authority should contact the flooring manufacturer or supplier for types and colour range available.
- Flooring Inserts: Proprietary metal inserts (usually brass) for game equipment (net posts, etc.) and floor outlets (electrical service power outlets and sound system plug-ins / microphone jacks) with the type to suit use requirements and flooring assembly.

6 • SPECIALTY HARDWOOD FLOORING

.01 Strip Block Flooring: This type of flooring consists of selected kiln-dried edge grain wood blocks that are precision machined on four sides, turned on end (to expose end grain), and assembled with soft aluminium wire splines into flexible strips. Tongue and groove construction is also an option with some manufacturers.

Thicknesses: Nominal 25 mm (1"), 38 mm (1 1/2"), 50 mm (2"), or 65 mm (2-1/2").

Strip Width: 89 mm (3-1/2") to 140 mm (5-1/2").

Strip Length: Random for strip pattern, or specified length for parquet patterns.

Edges: Bottom edges bevelled and backside grooved for surplus mastic.

Patterns: Available in Strip Pattern or Parquet Pattern (right angle).

Species: Available in Douglas Fir, Hemlock, or Alder.

Grading: To flooring manufacturer's standards for specie selected.

Finish: Factory sanded with 40 grit or unfinished for final sanding and finishing on site.

Installation: Glue down installation over an acceptable substrate in accordance with flooring manufacturer's recommendations and applicable grading association (e.g. NOFMA) and NFCA requirements.

Availability: Limited - refer to specific manufacturer / supplier.

Note: this type of "end grain" hardwood flooring is very durable.

.02 Acrylic Impregnated Wood Flooring:

This "pre-finished" type of flooring consists of a hardwood species which has been subjected to an acrylic impregnation process that uniformly dyes and permanently infuses a "built-in" acrylic finish to the hardwood. This process forces an acrylic plastic (methyl-acrylate monomer) into the full cell structure of the wood utilizing a vacuum / pressure cycle. Fire retardant additives may also be included during this impregnation process in order to provide a flame spread rating where required. After the wood is impregnated, the composite is subjected to further treatment to produce high abrasion resistance and hardness.

Thickness: 8 mm (5/16") (verify with acrylic/wood flooring manufacturer or supplier).

Sizes: Various, depending on pattern selection (Design Authority should contact acrylic/wood flooring manufacturer or supplier).

Styles: Available in Strip, Plank, Parquet, Brick, and Tile flooring.

Patterns: Available only in limited patterns (verify with acrylic/wood flooring manufacturer or supplier).

Species: Available in Oak, Ash, Maple, and Walnut, although others may also be available.

Grading: To manufacturer's standard for species selected.

Finish: Factory finished or unfinished for sanding and finishing on site.

Installation: May be loose laid or floated (for engineered flooring with mechanically fastened joints), mechanically fastened (side nailed or stapled in tongue) with or without acoustical underlayment or glued down (but any method not directly to concrete) over an acceptable substrate in accordance with manufacturer's recommendations and applicable grading association (e.g. NOFMA) and NFCA requirements.

Availability: Somewhat limited - refer to specific manufacturer / supplier.

.03 Reclaimed Hardwood Flooring: This type of flooring consists of hardwood strips and planks that are milled from salvaged / reclaimed lumber (timbers and lumber) or are remanufactured / re-milled from existing hardwood plank flooring. Such flooring may be sanded and factory or site finished. Those producing such flooring should be contacted in regard to the species and sizes available.

.04 Recycled Hardwood Flooring: This type of flooring consists of existing hardwood strips and planks that have been salvaged (removed) form one location and reinstalled and refinished in a new location.

7 • HARDWOOD FLOORING EDGES

.01 Solid and engineered hardwood flooring (primarily planks) is milled with square, eased, or bevelled edges. The latter (eased and bevelled edges) serve a purpose in that when such boards are installed over irregular substrate surfaces the edges aid in eliminating "overwood" or slightly raised adjacent surfaces between boards. In addition hardwood manufacturers can produce bevelled edge boards faster than square edge, which in turn lowers their production costs (achieving consistently square edged material in a production run is more difficult).

.02 Square Edges

The edges of all boards meet squarely creating a uniform, smooth surface that blends the floor together from board to board.

.03 Eased Edges

The longitudinal edges of all boards, and usually the end joints, are slightly rounded or eased (usually accomplished by a light sanding).

.04 Bevelled Edges

The longitudinal edges are bevelled at 45 degrees resulting in a very distinctive groove between adjacent boards. A smaller bevelled or micro-bevelled edge (similar to an eased edge) may sometimes be used for a less distinctive groove.

.05 Lippage (under/over wood)

Acceptable tolerance:
Finished Engineered = .31mm (.012")
Character Grade Engineered = .63mm (.025")
Beveled Edge 3/4" Pre-finished solid wood: .36mm (.014") (+or- 1/64)
Micro Beveled Edge 3/4" Prefinished Solid Wood: .31mm (.012")
Wide Plank Character 3/4" Prefinished Solid Wood: .79mm (.031) (+or- 1/32")

8 • HARDWOOD FLOORING TEXTURES AND PATTERNS

.01 Solid and engineered hardwood flooring (primarily planks) can be "textured" by various means to achieve a desired (usually antique) look. This may be achieved by a variety of methods:

Hit or Miss:

This method leaves some of the sawing "kerf" marks on the exposed (top) faces to achieve the antique look of old flooring crafted with less precise tolls.

Wire Brushing:

Wire Brushing the surface of the flooring (by hand or mechanically ) digs in to the softer graines leaving more cavities. When finish is applied the brushing effect highlights the natural grain charactersitic of the wood species. Wire brushing works particularly well with oak.

Handscraping:

This method is used to achieve the look of handcrafted "foot worn" flooring where flooring (planks) were sawn using basic hand-held tools that resulted in variations of texture and over time were worn by traffic. The top and edges of new flooring are scraped to achieve a rustic and foot worn look.

.02 In addition to texturing other ways to achieve variations in design may be used. This may be done in a number of ways:

Mixed Widths:

This decorative method, used primarily in plank flooring, uses boards (planks or strips) of various widths to achieve a different appearance.

Patterned Layouts:

This decorative method is used primarily with short pieces of strip flooring and parquet tile flooring. Hardwood strips may be installed in various pattern arrangements some of which include Monticello, Haddon Hall, Herringbone, Saxony, Canterbury, Rhombs, Basket Weave, Italian & Domino, and Chaucer patterns. Parquet tile can be laid in a chequer board or basket weave patterns. Refer to Part DD3 - Parquet Patterns for patterns.

Mixed Species:

This method uses species having different grain patterns and colours / stains which may include both domestic and imported woods. This method may be used with the different strip, plank, and parquet flooring elements installed in large-scale sizes (bands, borders, fields).

Borders and Inlays:

This method (usually used in strip flooring) uses thin strips of different coloured hardwood flooring that are usually inserted around the perimeter of the flooring to "frame" or define the area or field and customize the installation. This decorative trim may be simple or intricate in design, particularly at the corners. An intricate border calls for a simple field, and vice versa. Care should be exercised in keeping the border's width in scale with the floor area (room). For example, a 300 mm (12") wide border would be out of proportion with a 1200 mm (48") wide hallway.

Bordering Inserts:

This methods uses prefabricated "custom" or "standard" hardwood elements set into the field of flooring for special purposes or decorative effects. These may be "medallions" and other inlays that are either pre-manufactured or custom-made at the job site, and should always be installed after the floor is installed to ensure a properly tight fit. A router should be used to cut out the area needed for the medallion.

Mixed Media:

This method uses different materials in addition to hardwood flooring, such as ceramic and stone (marble, slate, etc.) tile, and even brass.

Painted or Stenciled Flooring:

This decorative method uses an appropriate paint compatible with the hardwood species and finish applied to the flooring surface by a qualified trades person, designer, or "artist" to create unique patterns. This may include pattered borders, checkerboard pattern, faux rugs or tiles.

9 • HARDWOOD FLOORING MOLDINGS, TRIMS, AND ACCESSORIES

.01 Various hardwood moldings and trims are used in conjunction with hardwood flooring: Such mouldings are used to cover the perimeter expansion gap, to hide cut ends, to provide a perimeter base, and in some cases to accent the floor. These include such items as:

Reducer or Transition Strips / Thresholds:
used to make a transition from hardwood flooring down to other usually thinner flooring materials such as ceramic tile, carpet, and resilient flooring, as well as at doorways. Material from 10 mm (3/8") to 19 mm (3/4") thick and 25 mm (1") to 64 mm (2-1/2") wide.
- T-Strip Moldings: used at field expansion joints and at changes in direction of flooring materials. These moldings cover the gap and allow for flooring expansion.
  - Expansion Joint Strips: void filler for expansion space at the perimeter edge of flooring with the width to suit expansion joint gap. Cork or closed cell polystyrene strips are typically used.
  - Wood Base: used to protect wall and "picture-frame" hardwood flooring installations. Material from 10 mm (3/8") to 16 mm (5/8") thick and from 38 mm (1-1/2") to 102 mm (4") high. Various shapes are available including Cove, Modern, or Streamline, Decorative or Combination.
  - Base Shoe or Quarter Round: used on the vertical face of wood bases to complete expansion void coverage. Material is cut from one quarter of a full round of matching material as base and is usually 13 mm (1/2") to 25 mm (1") in size.
  - Floor Vents and Grilles: fixed or adjustable louvre type for hot and cold air circulation complete with flange fit, usually pre-finished metal although wood is also available (may be supplied by mechanical trade or by Owner).

Flush mount vent

.02 Material Criteria: The following shall govern when moldings and trim are provided by the hardwood flooring manufacturer:

Species: Type to match hardwood flooring.

Finish: Factory sanded and unfinished ready for finishing on site or pre-finished to match flooring.

Installation: Method and materials to suit design requirements, flooring manufacturer's recommendations, and hardwood flooring association details, using concealed or surface type fasteners and/or adhesive in accordance with design requirements.

10 • HARDWOOD STAIRS

.01 When included and required to match adjacent hardwood flooring installations, hardwood stair landings, stair treads / nosings, risers, stringers, and companion trims shall be provided by the hardwood flooring manufacturer: Such items include:

Stair Treads: horizontal part or tread of stairs complete with nosing. Material from 25 mm (1") to 27 mm (1-1/16") thick x 200 mm (8") to 300 mm (12") wide or as required.

Nosings: used to create a finished edge on hardwood stair landings, on stair treads with different tread finish material, as a trim on open floor edges, etc. Thickness to be the same as hardwood flooring, unless otherwise required and pre-approved by authorities having jurisdiction (e.g. over-lap nosings).

Stair Risers: used to create the vertical rise in the step. Usually 19 mm (3/4") thick x width of stair.

Stair Stringers: used against wall surfaces at stairs or as side trim under treads and risers on open stairs (as well as at landings and open balconies where detailed). Material to match base height and thickness at landings and be coped around stair treads / nosings and risers as required.

.02 Material Criteria: The following shall govern when stair components are provided by the hardwood flooring manufacturer:

Species: Type to match hardwood flooring.

Grading: Grade to match hardwood flooring as applicable.

Finish: Factory sanded and unfinished ready for finishing on site or pre-finished to match flooring.

Installation: Method and materials to suit design requirements, flooring manufacturer's recommendations, and hardwood flooring association details, using concealed or surface type fasteners and/or adhesive in accordance with design requirements.

11 • HARDWOOD FLOORING UNDERLAYMENTS

.01 Rational: Various materials are used as underlayments under hardwood and engineered flooring installations for a variety of reasons. These may include one of or a combination of the following reasons:

To even out minor substrate surface imperfections to provide a smooth level surface. This may includes the use of a patching compound or a sheet material.

To act as a moisture retarder thereby protecting the flooring assembly from substrate moisture.

To improve the acoustical performance (particularly in regard to impact noise reduction) of the flooring installation.

To improve thermal performance of the flooring assembly.

To cushion the flooring installation thereby reducing walking fatigue.

.02 Materials: There are a variety of materials that may be included as underlayments in order to fulfil the above noted use requirements:

Floor Patch / Fillers: This material is used for minor patching, filling / levelling, and substrate preparation only in accordance with NFCA requirements and as defined by local trade jurisdiction requirements. For additional information refer to NFCA Reference Manual Part A13 - Patching and Filling.

Moisture Retarder Membrane: This sheet membrane, typically minimum1.5 mm (6 mil) polyethylene, is installed over concrete slabs-on-grade to act as a "moisture barrier." The method of installation must conform to Building Code requirements in regard to taping and sealing of joints and tears.

Separation Membrane or Lining Felt: This sheet membrane is occasionally specified for use under strip wood or plank flooring to keep out dust, retard moisture movement from below, and help to prevent squeaks in dry seasons. The type used must be as recommended by the hardwood flooring manufacturer for the type of substrate and conditions that apply.

Underlayments: "resilient" sheet form material must be of a type and thickness (between 3 mm (1/8") to 6 mm (1/4") thick) as recommended by the flooring manufacturer, accepted by NFCA, and pre-approved by authorities having jurisdiction for the type of installation, substrate, and conditions that apply.
The following are some materials that may be used as underlayments subject to floor manufacturer's recommendations and approval:
- Cork (typically in roll form).
- Granulated or sponge rubber sheet.
- Natural or synthetic fibre.
- Polyethylene, polypropylene, polyurethane, vinyl, or frothed foam.
- Polystyrene granules (encased in suitable wrapping).
Note: underlayments for sports flooring systems are part of the flooring system and shall be as specified by the hardwood sports flooring manufacturer.

.03 Performance Criteria: Material used as underlayments must be evaluated and selected with the following criteria in mind where appropriate:

Water Vapour Transmission Properties: The permeability of an underlayment is important particularly when it is used on concrete substrates below, on, or just above grade conditions. Standard methods based on ASTM F1249 and ASTM E96 for the evaluation of moisture resistance properties determine the rate of water vapour transmission through a given barrier material. The resultant water vapour transmission rate (WVTR) is the rate of water vapour flow per unit area over a specified time interval based and on steady-state conditions.

Acoustical Properties (contribution of the underlayment to reduction of the impact noise rating of the total flooring system): Note that any acoustical rating attributed to any underlayment must be verifiable by third party independent testing. Refer to A08C - Acoustical Issues for additional information.
Note: The installation of any acoustical underlayment must be done in strict accordance with the manufacturer's recommendations and acoustical design requirements. In addition, mechanical fasteners that will penetrate the sound material must not be used as the integrity of the sound control material can be jeopardized. For example any impact noise from above will travel through the fasteners to the substrate surface below.
- Thermal Resistance Properties (contribution of the underlayment to thermal performance rating of the total flooring system): Thermal resistance (RSI or R-value) is the reciprocal of thermal conductance (C-value). C-value is calculated from the thermal conductivity (k) of a material. Thermal conductivity (k) is the measure of the amount of heat that will be transmitted through a 25 mm (1") thick piece of homogenous material, 300 mm (12") square in size, in one hour, when there is a one degree temperature change.
- Compression Resistance: Compression resistance is the measurement of the force necessary to produce a specified percentage of compression over the entire top area of a given sample. ASTM D3575, ASTM D1667, and ASTM D3676 are testing methods used to compare flooring underlayment products. The accepted percentage of compression for any of these test methods is 25% of thickness. Results are expressed in either kPa or psi. The specific method selected should be noted when reporting results.
- Compression Set: This covers the deflection of an underlayment specimen under a compressive force and under specified conditions of time and temperature, then noting the effect on the thickness of the specimen after releasing the compressive force. The results are reported as a percentage of the original thickness. Both ASTM D1667 and ASTM D3575 test methods are accepted procedures for measuring compression set. Both tests require deflection for a period of 22 hrs and release for a period of 24 hrs. The tests differ in the thickness of deflection (25% and 50%). The thickness of the test deflection should be noted along with the specific method selected when reporting results.
- Tensile Strength: This is the measurement of the force needed to separate or tear the underlayment, i.e., the tear resistance. Tensile strength measurements may help compare underlayment materials in regard to ease of installation and long-term wear-ability. Standard methods for the evaluation of tensile strength are conducted for both the length and width of the test material and are reported in kgs or lbs of force.
- Density: Volume density is the ratio of the mass weight of the underlayment to its volume. Density is calculated from thickness and weight determinations and expressed in kilograms per cubic meter or pounds per cubic foot.
- Weight: This is usually expressed in grams (or kg) per square meter or lbs (or ounces) per square foot. Weight comparison may be an important characteristic when considering job site material management, ease of installation, and freight costs.
- Thickness: normally measured in millimetres, inches, or mils, thickness is important when evaluating the finished flooring profile height as it relates to adjacent flooring materials and doorway clearances.

12 • HARDWOOD FLOORING ADHESIVES

.01 Adhesives:

There are a number of adhesives and mastics specially formulated for use in glue down applications of hardwood flooring. The type and application of adhesives shall be as recommended by both the material and adhesive manufacturer to suit the substrate type, the type of hardwood flooring and the type of application required.

Caution Note: The design authority / specification writer is cautioned against specifying a particular manufacturer or type of adhesive as each hardwood flooring manufacturer may have specific recommendations in regard to the type and usage of adhesives for their particular products and installations. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify adhesives "as recommended by the hardwood flooring manufacturer to suit installation requirements". The grade (standard or premium) and the type (based on VOC content as well as use of water resistant or water proof types) should however be noted where applicable.

LEED Requirements: Where the flooring installation must conform to LEED requirements, the type of adhesives used throughout (i.e., for installation of underlayment panels, flooring, bases, and accessories) shall be governed by those requirements.

Refer to Part A14 - Adhesives and Fastenings for general adhesive information.

Since hardwood flooring moves under deflection (if installed using a resilient system) and with changes in humidity, any adhesive used to adhere the flooring to the substrate or strips, boards, parquet, or laminated panels to each other, must remain resilient and allow this movement without breaking the bond. Adhesives should also be non-flammable and have high green grab (tack), a long working time, and high strength.

.02 Application:

The appropriate adhesive, trowel notch size, spread rate, and application technique shall be as recommended by the hardwood flooring and adhesive manufacturers.

The trowel notch must be large enough to apply a continuous film (i.e. full coverage) of the adhesive to the substrate to ensure a minimum of 85% transfer of the adhesive to the underside of the hardwood flooring.

The adhesive must be spread uniformly over the substrate surface using the correct trowel and adhesive spread rates recommended by the manufacturer for the type of substrate and hardwood flooring.

The hardwood flooring is then installed over the adhesive and if pre-approved by the manufacturer rolled with an appropriate roller to ensure full contact of the adhesive.

13 • HARDWOOD FLOORING FASTENINGS

.01 Fasteners:

There are a variety of mechanical fasteners (nails, brads, staples, screws, etc.) and driving devices specially designed for use in mechanically fastening hardwood flooring and substrate assemblies (e.g., plywood subfloors, wood nailers / screeds, resilient systems, etc.). The selection of appropriate fasteners should therefore be done in strict accordance with the flooring manufacturers recommendations for the materials and conditions that apply.

Fasteners for flooring must be non-corrosive so as not stain flooring and in the case of pressure or fire resistant treated materials must be hot dipped galvanized or stainless steel. Refer to NOFMA Nailing schedule (Appendix Part DD2) for detail description of nails, staples, and machine driven fasteners.

Note: The specifier is cautioned against specifying a particular type of fastener, as each manufacturer will recommend specific types for a particular application. Fastener types used must be manufactured by or approved by the hardwood flooring manufacturer. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify fasteners "as recommended by the hardwood flooring manufacturer to suit installation requirements".

.02 Installation:

Tongue and grooved flooring is usually blind-nailed, except at perimeters or where used as a decorative feature (e.g. screw and plug fastening). Square butt edge flooring must be faced-nailed. Refer to NOFMA Nailing Schedule (Appendix Part DD2) for recommended size and spacing of nails and staples.

14 • SPECIAL INSTALLATION SYSTEMS

.01 Mechanical Systems: These are proprietary "floating" or "clip attached" installation systems that are available from some hardwood flooring manufacturers.

.02 Glue-Less Systems: These are "proprietary" engineered hardwood flooring installation systems that use a mechanical (friction fit or locking) connection between boards or               panels only (i.e., no adhesive is used).

Note: The design authority should contact the hardwood or engineered flooring manufacturer or supplier for details and availability of such systems.

.03 Installation: Installation of flooring components using these types of systems must be done in strict accordance with flooring manufacturer's written recommendations and               NFCA minimum requirements. Such installations are usually done over an acoustical underlayment for absorption of any airborne or impact noise.

.04 Removal: Removal of mechanical and glue-less flooring components may be easy or difficult, and/or may damage the flooring. Where such flooring is expected to be removed       for one reason or another or for repair, etc., the ease of removal should be verified with the manufacturer before it is installed and appropriate tools and maintenance materials           should be provided.

15 • SPECIAL INSTALLATION REQUIREMENTS

.01 Radiant Heated Flooring Systems:The use of solid hardwood flooring over radiant heated flooring is subject to the hardwood flooring manufacturer's recommendations. As a general rule most hardwood flooring manufacturers do not recommend or will not warrant the installation of solid hardwood flooring over radiant heated floors (due to excessive shrinkage) but will recommend and warrant engineered flooring over such heating.

.02 If solid hardwood flooring is being contemplated for use over radiant heated floors the following factors must be considered:

Certain Species are known for their inherent dimensional stability such as American Cherry, American Walnut, Mesquite, Teak and others. Other species such as Maple and Brazilian Cherry are less stable. The manufacturer / supplier of hardwood flooring must be consulted in regard to species suitability.

Quarter sawn or rift sawn wood flooring is more dimensionally stable than plain sawn wood flooring.

Narrow boards, 57 mm (2 1/4") or less in width, are the best choice of solid wood flooring over radiant heated floors.

16 • HARDWOOD FINISHING

.01 For an explanation of site and factory finishing refer to Part D04D – Installation Guide - Finishing.