Flooring Installation Instructions

IMPORTANT! Please be sure to read these instructions completely before beginning installation. By installing this flooring, you acknowledge and accept the following:

• The installer assumes all responsibility for final inspection of product quality. This inspection of all flooring should be done before installation. Carefully examine flooring for color, finish and quality before installing it.
If material is not acceptable, do not install it and contact the seller immediately.

• Prior to installation of any hardwood-flooring product, the installer must determine that the job-site environment and the sub-surfaces involved meet or exceed all applicable standards and recommendations of the construction and materials industries.
These instructions recommend that the subfloor be dry, stiff and flat, thermostat/humidistat set to regular living setting and the flooring acclimated under this setting.
The manufacturer declines any responsibility for job failure resulting from or associated with sub-surface or job-site environment deficiencies.

• During installation, the installer must use reasonable selectivity and hold out or cut off pieces with defects, whatever the cause.
Should an individual piece be doubtful as to grade, manufacture or factory finish, the installer should not use the piece.

• Use of stain, filler or putty stick for defect correction during installation should be accepted as normal procedure.

• When flooring is ordered, add 5% to the actual square footage needed, for cutting and grading allowance.

• Use of appropriate products for correcting subfloor voids should be accepted as a normal industry practice.

• Follow NWFA Installation Guidelines if any of the instructions in this manual differ from or conflict with the former.

Before you begin, make sure you have the following tools.

Job Site Inspection

• The building should be closed in with all outside doors and windows in place. All concrete, masonry, framing members, drywall, paint and other “wet” work should be thoroughly dry.

• The wall coverings should be in place and the painting completed except for the final coat on the base molding. When possible, delay installation of base molding until flooring installation is complete.

• Exterior grading should be complete with surface drainage directing water away from the building. All gutters and downspouts should be in place.

• Basements and crawl spaces must be dry and well-ventilated, and meet the minimum requirements of the International Residential Code (IRC), as detailed in IRC Section R408.

• Subfloor must be checked for moisture content (MC) using the appropriate testing method.

• Air conditioning and heating systems should be in place and operational. The thermostat and humidistat should be set at normal living levels, with recommended temperature of 60 – 75° F and relative humidity (humidity) of 30 – 50%, at least seven days prior to installation. This humidity range between 30% and 50% should be maintained during acclimation, installation, and after installed.

Storage & Acclimation

• Handle and unload cartons with care. Cartons should be stored on “on-grade” concrete floors, in a location with at least a 4” air space under the cartons. Flooring should not be delivered until the building has been closed in, with windows and doors in place and until cement work, plastering and all other “wet” work is completed and dry. Concrete should be at least 60-days old before moisture testing should take place.

• Acclimate the flooring under occupied conditions until the flooring’s moisture content (MC) and temperature reach equilibrium of moisture content (EMC), which may take 1 to 4 weeks, depending on the environment and the flooring. Within the recommended range of temperature (60° – 75° F) and relative humidity (RH) (30% – 50%, or 35% – 55%), the EMC is primarily a function of the relative humidity and can be estimated by using the chart below:

• Determine the indoor RH range and the corresponding EMC in the home/construction. The indoor RH range depends on local weather conditions, cooling/heating system used, and living habits. In some extremely humid or dry locations or on extremely dry or humid days, additional dehumidification or humidification may be needed to keep the RH within the 30% – 50% range.

• Ensure facility is capable of, and being maintained at normal living conditions, as defined within these instructions. Moisture content of the floor relies on these conditions. For example, if the humidistat is set to 40% and the indoor RH fluctuates between 35% and 45%, then the flooring MC should be around 6.9% – 8.5% before installation.

• For solid flooring acclimation, open the packages onsite, under occupied conditions. Normal acclimation time is 10 – 14 days, but more time may be required, depending on the environmental conditions as compared to the flooring MC level. Measure the flooring MC before installation to ensure the flooring is properly acclimated.

• For engineered flooring, do not open packages until you are ready to install. Ensure the facility is capable of, and being maintained at, a temperature 60 – 75F and an RH 30 – 50%” Once this has been validated, and documented, you may install the flooring.

Doorway & Wall Preparation

Undercut door casings. Remove, if any, existing base, shoe molding or doorway thresholds. These items can be replaced after installation. All door casings should be notched out or undercut to avoid difficult scribe cuts.

Inspect the Flooring before Installation

Real wood and bamboo flooring contains natural variations in color and grain pattern. In order to prevent color grouping or repetitive grain patterns in the finished floor, it is recommended that several packages be opened and that boards from each of these packages be racked (sorted to be visually pleasing) before the floor is permanently installed.

• Immediately prior to installation, unpack 1 to 3 cartons to get a sense of the range of color variation and arrange the planks to achieve a satisfactory appearance (rack the boards).

• When racking, inspect all boards for visible manufacturing defects. Do not install any defected boards. Boards with manufacturing defects in excess of industry standards (5% of total quantity) may be replaced by the dealer under the terms of the product warranty. Once installed, boards will be considered to have been accepted by the customer and will not be eligible for replacement (See Warranty for details).

• Be attentive to staggering the ends of boards in adjacent rows at least 6″ when possible. This will help ensure a more pleasant overall appearance of the floor.

Subfloor Types and Requirements: See Appendix A

Radiant Heat: See Appendix B

Estimate Dimensional Movement: See Appendix C

Sound Control: See Appendix D

Moisture Testing & Vapor Retarders: See Appendix E

Installation procedures, Solid vs Engineered flooring.

While both Engineered and Solid hardwood flooring share many similarities in installation procedures, there are a few very distinct differences. Please follow these instructions closely to avoid potential damage to your flooring, or possibly voiding your manufacture’s warranty. *The type of installation method to choose depends upon many factors such as flooring construction (solid or engineered) and subfloor type.

Note: The general requirement for subfloors is flat, dry and structurally sound. Under these criteria, wood panels/solid board, concrete slab and other existing floor covering materials can all be used as subfloor.

Wood Panels & Solid Board Subfloors

The subfloors must be flat

• For nail/staple down installations, the subfloor should be flat
to within 1/4” in 10 feet or 3/16” in 6 feet radius.

• For glue-down and floating installations and installations using mechanical fasteners of less than 1-1/2”, the subfloor should be flat to within 3/16” in 10 feet or 1/8” in 6 feet radius.

• Edge swell should also be flattened. This can usually be accomplished by using an edger sander.

• Make sure the subfloor is free of debris before beginning installation.

The subfloors must be dry

• Installers should know the MC of the subfloor and the flooring. There should be no more than 2 percent difference in MC between properly acclimated wood flooring and subflooring materials before installation.

• Ensure that there is proper expansion space (1/8”) between the panels. If the subfloor panels are not tongue and grooved and if there is not sufficient expansion space, use a circular saw to create the specified space. Do not saw through joints on T&G subfloors.

The subfloors must be structurally sound

• Inspect the subfloor carefully. If there is movement or squeaks in the subfloor, refasten the subfloor to the joists in problem areas. Protruding fasteners are easily remedied by driving those fasteners deeper into the subfloor.

• Check for delaminated or damaged areas and repair those areas as needed.

Acceptable Panel Subfloors:

• On truss/joist spacing of 16” (406mm) o/c or less, the industry standard for single-panel subflooring is minimum 5/8” (19/32”, 15.1mm) CD Exposure 1 Plywood subfloor panels (CD Exposure 1) or 23/32 OSB Exposure 1 subfloor panels, 4’ x 8′ sheets.

• On truss/joist spacing of more than 16”, up to 19.2″ (488mm) o/c, the standard is minimum 3/4” (23/32”, 18.3mm) T&G CD Exposure 1 Plywood subfloor panels, (Exposure 1), 4’ x 8′ sheets, glued and mechanically fastened, or minimum ¾” (23/32″, 18.3mm) OSB Exposure 1 subfloor panels, 4’ x 8’ sheet glued and mechanically fastened.

• Truss/joist systems spaced over more than 19.2” (488mm) o/c up to a maximum of 24” (610 mm) require minimum 7/8” T&G CD Exposure 1 Plywood subfloor panels, (Exposure 1), 4’ x 8′ sheets, glued and mechanically fastened, or nominal 1” OSB Exposure 1 subfloor panels, 4’ x 8’ sheets, glued in accordance with the truss/joist manufacturer’s recommendations and with local building codes. Some truss/joist systems cannot be cross-braced and still maintain stability.

• For double-layer subfloors, the first layer should consist of nominal 3/4” (23/32”, 18.3mm) CD Exposure 1 Plywood subfloor panels (CDX), 4’ x 8′ sheets or nominal 3/4” (23/32”, 18.3mm) OSB Exposure 1 subfloor panels, 4’ x 8’ sheets. The second layer should consist of nominal 1/2” (15/32”, 11.9mm) CD Exposure 1 plywood subfloor panels, (Exposure 1) 4’ x 8’ sheets. The 1/2” plywood should be offset by 1/2” panels in each direction to the existing subflooring. The panels may also be laid on a diagonal or perpendicular, with 1/8” spacing between sheets. Nail on a 12” minimum grid pattern, using ring shank nails or staples.

• Typical panel spacing and fastening requirements for truss/joist systems call for approximately 1/8” expansion space around the perimeter of each panel, with panels fastened every 12” (305 mm) along intermediate supports.

Acceptable Solid Subfloors:

• Allwood Solid Hardwood Collection (3/4” in thickness) can be installed directly over solid-board subflooring. Other collections must have a 3/8” or better plywood underlayment installed over solid board subflooring.

• Solid board subflooring should be: 3/4” x 5-1/2” (1” x 6”), Group 1 dense softwoods (SYP, Doug Fir, Larch, etc.), No. 2 Common, kiln-dried.

• Solid-board subflooring should consist of boards no wider than 6”, installed on a 45-degree angle, with all board ends full bearing on the joists and fastened with minimum 8d rosin-coated or ring-shanked nails, or equivalent.

Concrete Subfloors

The subfloors must be flat

• Flatness tolerance of 1/8”in a 6-foot radius and or 3/16” in a 10-foot radius. Many high spots can be removed by grinding, depressions can be filled with approved patching compounds, and slabs also can be flattened using a self-leveling concrete product.

• When sanding or grinding concrete, care must be taken to minimize the amount of silica dust produced. OSHA recommends using dust-collection devices, or applying water to the concrete before sanding. Approved respirators may also be used to minimize the amount of silica dust inhaled.

• The surface should be free from non-compatible sealers, waxes, oil, paint, drywall compound, etc. Check for the presence of sealers by applying drops of water to the slab. If the water beads up, there may be sealers or oils.

• Burnished or slick slabs may require screening or sanding with
a 30-grit abrasive.

The subfloors must be dry

• NWFA guidelines specify using relative-humidity testing (ASTM F2170), calcium chloride testing (ASTM F1869) to identify the MC of the slab.

• Always use a class I vapor retarder when installing on, and below grade. When installing on an elevated slab, it is recommended, but not always necessary, depending on the moisture conditions of the slab.

The subfloors must be structurally sound

• Minimum 3000 psi.

• Over lightweight concrete (less than 3000 psi), if the flooring adhesive used has a higher shear strength than the concrete, use the floated subfloor installation method.

• If the psi of the concrete is unknown, use the floated subfloor installation method or contact the adhesive manufacturer. Rule of thumb: Draw a nail across the top; if it leaves an indentation, it is probably lightweight concrete.

• Do not attempt to glue a wood floor over a chalky or soft concrete slab.

• Allwood engineered and solid flooring collections cannot be installed directly over screed system, but the screed system needs to be overlaid with proper subflooring. The screed system must be overlaid with 23/32” Exposure 1 plywood subfloor panels, or 19/32” (15.1 mm), Exposure 1 plywood subfloor panels or 23/32” OSB Exposure 1 properly spaced and oriented perpendicular to screed direction, and across two or more spans.

Other Existing Surfaces as Subfloors

Acoustic Concrete*

Acoustic concrete normally contains large quantities of gypsum that may inhibit the adhesive’s capability to properly bond. For glue-down applications, acoustic concrete must be primed with the concrete manufacturer’s recommended primer/surface hardener. Resilient Tile, Resilient Sheet Vinyl & Cork Flooring (For Floating or Glue Down Installation Only).

If the tiles or sheet goods are well bonded, the flooring can be glued directly to the surface. Clean the surface thoroughly with a good quality household detergent. De-gloss flooring as necessary to create a good adhesive bond using an abrasive pad. If vinyl appears to have a coating of wax or other maintenance materials, it must be removed with the appropriate floor stripper. Allow ample drying time.

Note: Do not sand any resilient products for they may contain asbestos fibers, which may be harmful.

Do not direct glue to floors that exceed two layers; install as a floating system only under these circumstances. Cork floors must have all sealers and surface treatments removed before installation begins if a direct glue-down application is preferred.

Ceramic, Terrazzo, Slate & Marble*

All grout joints and broken corners that exceed 1″ must be filled with leveling compound mixed with Latex additive of a glue-down application is preferred. The surface should be cleaned and abraded to create a good bonding surface for the adhesive. Loose tiles must be re-adhered to the subfloor or filled as above for both glue-down and floated applications.

Cork (Acoustic)*

Floating floors can be glued or floated directly over full-spread, permanently bonded acoustic cork. The cork should have a density of no less than 11.4 lb/cubic foot and no more than 13 lb/cubic foot. The cork, in general, should be pure cork combined with a polyurethane binder. Cork thickness is to be no more than 1/4” (6 mm). Install cork in accordance with manufacturer’s recommendations. Do not use cushion underlayment when floating over cork surfaces.

Installing Wood Panels Over Concrete

Floated Subfloor Installation — Method One

• Add vapor retarder before applying underlayment, unless the underlayment is a vapor retarder itself.

• Panel Material: 2 layers minimum 3/8” (10 mm) minimum CD Exposure 1 Plywood subfloor panels (CDX) 4’ x 8′ sheets.

• Place the first plywood layer with edges parallel to wall, without fastening. Leave 3/4” space between wall and plywood.

• Lay second layer perpendicular or at 45 degree angle to the first.

• Plywood panels should be placed with 1/8” gaps between sheets and a 3/4” minimum expansion space at all vertical obstructions and along wall lines.

• Using urethane or construction adhesive, taple/screw and glue the second layer to first layer on 12” interior grid pattern (6” on the perimeter). Be careful not to penetrate the vapor retarder.

Floated Subfloor Installation — Method Two

• Add vapor retarder before applying underlayment, unless the underlayment is a vapor retarder itself.

• Alternate Wood panels: Use minimum 3/4” (23/32”, 18.3 mm) CD Exposure 1 Plywood sheathing, 4’ x 8’ sheets.

• Cut sheets to 16” x 8’ or smaller panels, scored on back 3/8” deep a minimum of every 12” across width.

• 16” planks oriented perpendicular or diagonally to the direction of the flooring.

• Panels staggered every 2’, and spaced 1/8” between ends, with 3/4” minimum expansion space at all vertical obstructions.

Glue-Down Subfloor Installation

• Always follow the adhesive manufacturer’s recommendation for proper subfloor, spread rate and trowel notch.

• Add vapor retarder before applying underlayment.

• Panel Material: Use minimum 3/4” (23/32, 18.3mm) CD Exposure 1 Plywood subfloor panels, (Exposure 1), 4’ x 8’ sheets.

• Cut the plywood panels to 2’ x 8’ or 4’ x 4’ sections.

Allwood Engineered Hardwood Collections and Classic Bamboo Engineered Collection can be installed over radiant heat as long as the guidelines below are followed.

Max allowable subfloor surface temperature is 80° F.

Even distribution of heat, heating system and  subfloor materials

With water-heated radiant-heat systems, a pressure test must be performed and documented by a qualified plumber or the system installer prior to beginning the installation of the wood flooring. Electric under floor systems should also be tested prior to floor installation. Check heat system manufacturer guidelines. If flooring materials that conduct heat at different rates are on the same circuit or heating zone, check with the HVAC mechanical engineer and Radiant Panel Association before proceeding. Radiant-heated subfloor systems can be concrete, wood or a combination of both, as long as the material will distribute heat evenly.

The vapor retarder and the subfloor moisture content

Humid heat is to be avoided by using proper vapor retarder and dry subfloor, or a system to prevent moisture accumulation under the flooring. A 6-mil or better polyethylene vapor retarder and a foam or resilient underlayment should be installed over subfloors. Turn the heat on, regardless of the season, and leave it on for at least 5 – 6 days until the subfloor MC has dropped below 9%. Turn off the heat before the installation of the flooring begins, so the adhesive does not cure too quickly.

Flooring moisture content

The average Moisture Content of Allwood flooring is 7%, with limited moisture gain or loss (1%) during transportation and storage before the boxes are opened. The floor should be acclimated to 6% – 7% before installation.

Indoor humidity control

The indoor air humidity should be maintained at 50% – 60% or no less than 40% once the heat is turned on. For example, with radiant heat on at 85° F, the floor EMC is about 7% at 60% indoor air humidity and at 68° F temperature, EMC 6% at 50% humidity, and EMC 5.4% at 40% humidity. The indoor air humidity should be maintained at 30% – 40% or no more than 50% once the heat is turned off. For example, with radiant heat off, the floor EMC is about 6.2% at 30% indoor air humidity, EMC 7.7% at 40% humidity, and EMC 9.2% at 50% humidity.

Installation Methods

• Floating installation (recommended): Expect some heating season shrinkage and cooling season expansion. The flooring should be installed at the median MC between the lowest and highest EMC of the on and off heating season. For example, if you would like to control the humidity to 40% year round, the EMC will be between 5.4% – 7.7%, and the suggested floor MC at installation is 6.5%.

• Staple/nail and glue-down installation: Staple/nail-down can be used if dry heat is achieved and the indoor air humidity can be controlled within a very tight range, about 50 – 60% at heating season and 30% – 40% at off heat season. Be sure fasteners are not so long as to penetrate heating tubes or heat sources for nail/staple down installation. Make sure the moisture induced by the glue is dissipated before the radiant heat is turned on when using glue down method. Use the glue formulated for radiant heat. Read the label on the bottle or consult the manufacture.

Turn on the Radiant Heat

To minimize the effect that rapid changes in temperature will have on the MC of the wood floor, the temperature difference between the flooring and the indoor air should be kept at less than 10° F during the heating up process. As the indoor air is heating up, the humidity will decrease if there is not adequate humidification control. Make sure to maintain the humidity at the acceptable level as the temperature increases.

The floor temperature can be increased faster when indoor air humidity is higher.

Floor MC and Environment Control

With radiant heat, the heat source is directly beneath the flooring, so the flooring may dry out faster than a similar floor in a home with a conventional heating system. Wood flooring can be installed over radiant heat as long as you understand radiant heat and how it can impact wood flooring, what precautions to take, and what type of wood flooring to use.

Scenario 1 — Radiant Heat as dry heat to the floor

Assumptions: Proper vapor retarder has been installed to prevent excess humidity moving towards the flooring from beneath the flooring when it is heated. The subfloor has been properly acclimated to have the same MC as the floor or to be within 2% variation (eliminated another humidity source towards the floor).

Under this dry heat scenario, assume the floor is installed and heated to no greater than 80° F, and the room temperature is maintained at 68° F, then the floor EMC will be about:

4% @ 30% indoor humidity

5% @ 40% indoor humidity

6% @ 50% indoor humidity

7% @ 60% indoor humidity

Once the heat is turned off, and the room temperature is maintained at 68° F, then the floor EMC will be about:

6.2% @ 30% indoor humidity

7.7% @ 40% indoor humidity

9.2% @ 50% indoor humidity

11% @ 60% indoor humidity

Clearly, the floor should be acclimated to below 7% before installation. The indoor humidity should be maintained at 50% – 60% or no less than 40% once the heat is turned on. The indoor humidity should be maintained at 30% – 40% or no more than 50% once the heat is turned off.

Scenario 2 — Radiant Heat as humid heat to the floor.

Assumptions: Excess humidity from underneath the flooring is heated and moving towards the flooring. The subfloor has high MC (as another humidity source towards the floor). Under this humid heat scenario, moisture may accumulate between the radiant heat and the flooring, reaching saturation point (EMC up to 20%) for a period of time until the humidity is exhausted. The flooring would have high MC on the bottom side and lower MC on the top surface, which may cause the floor to buckle, cup and rupture.

Once the moisture is exhausted, the humid heat becomes dry heat, and Scenario I comes into play. The flooring will be dried to below 7% MC. Surface checks may appear, plus the remaining cupping. The wet-dry cycle may cause the floor to delaminate, which is most often the wood failure than the glue, because the glue used in the engineered flooring can mostly tolerate the severe condition. Clearly, the humid heat is to be avoided by using proper vapor retarder and dry subfloor, or a system to avoid the moisture accumulating under the flooring. Dry heat at higher indoor humidity and heat off at lower indoor humidity are the right settings.

Scenario 3 — Assume dry heat, indoor air temp 60° F

At 60% humidity of indoor air, the floor EMC is:

9.3% @ 65° F

8% @ 70° F

7% @ 75° F

6% @ 80° F

5.5% @ 85° F

At 50% humidity of indoor air the floor EMC is:

8% @ 65° F

7% @ 70° F

6.2% @ 75° F

5.4% @ 80° F

4.8% @ 85° F

Clearly, the floor temperature can be increased faster when indoor air humidity is higher. Suggestion: Use other heat source to keep the indoor air at 68 ° F or normal living temperature during installation and before turning on the radiant heat.

Scenario 4 — Assume dry heat, indoor air temp 50° F

At 60% humidity of indoor air, the floor EMC is:

7.0% @ 65° F

6.1% @ 70° F

5.4% @ 75° F

4.7% @ 80° F

4.1% @ 85° F

A 50% humidity of indoor air, the floor EMC is:

6.1% @ 65° F

5.3 % @ 70° F

4.6% @ 75° F

4.1% @ 80° F

3.5% @ 85° F

Clearly, the floor temperature should be increased at lower rate when indoor air temperature is lower. Suggestion: Use other heat source to keep the indoor air at 68° F or normal living temperature during installation and before turning on the radiant heat.

Hardwood flooring will shrink when it loses moisture to the surrounding air, and will expand when it gains moisture. Under the same environmental conditions, solid flooring will shrink or expand more than engineered flooring. The shrinkage coefficient for engineered flooring is unavailable from publications, due to structural differences of various kinds of engineered flooring and species used. A reasonable estimate is that engineered flooring will shrink or expand half as much as the solid flooring under the same environmental conditions. Allwood is not responsible for the actual shrinkage variation of engineered flooring from this estimation due to the unproven nature of it. Do experiment or have the experiment done when a more accurate estimate is needed. To estimate the potential dimensional changes of the solid wood flooring, you need to know the interior relative humidity (RH) variation range after the flooring is installed in. A humidistat or hygrostat will regulate the interior RH range and give you the data to calculate the potential dimensional movement of the flooring.

Potential Dimensional Movement

Potential Dimensional Movement can be estimated by the following: (Potential dimensional movement = shrinkage coefficient of the wood species x MC change x the width of the flooring).

For example, 3-1/4” solid oak (mostly flatsawn) is acclimated to 7% MC before installation, for a room of 20’ in width (about 77 rows). The interior humidity is to be controlled between 30% and 50% (EMC 6.2 – 9.2%) year round (with the help of air conditioning or additional humidification/dehumidification equipment if needed).

Known:

shrinkage coefficient = 0.00365

mc change @ 30% humidity = -0.8%

mc change @ 50% humidity = 2.2%

Then, accumulated potential dimensional change:

@ 30% RH, 0.00365*(-0.8)*240 = -0.7” (shrinking) (less than 1/64” per board).

@ 50% RH, 0.00365*(2.2)*240 = 1.9” (expansion) (less than 1/32” per board).

The potential dimensional change will be restrained by the neighboring boards, and will cause buckling/cupping/rupturing if too much expansion occurs or gapping if too much shrinkage occurs.

The rule of thumb is to control the RH within 20% variation which corresponds to 3% MC change, and the floor should be installed at a MC that is 1/3 – 1/2” from the lower end of the range. If MC of the floor is at the lower end of occupied RH range at the time of installation, spacers may be needed to allow future expansion. For example, if the flooring in the example above is installed in an interior with RH range 40% – 60% (EMC 7.7 – 11), then the potential dimensional change will be up to 3-1/2” (3/64” per board).

You may consider installing a spacer every a few rows.

In North America, there are two primary ratings used for sound control. They are Impact Insulation Class (IIC) and Sound

Transmission Class (STC). It is important to understand what these ratings mean as they relate to flooring selection and the installation method. A number of factors contribute to a room’s sound insulating ability.

Impact Insulation Class (IIC)

IIC, which stands for Impact Insulation Class, is a statistical measurement of the transmission of impact sound energy through a floor/ceiling assembly system (such as footsteps, dropped articles, or furniture moving across the floor). The larger the number, the more sound attenuation you have. The scale, like the decibel scale for sound, is logarithmic. IIC is measured and stated in accordance with ASTM E989 & C634, and is tested via ASTM E492.

• Delta (∆) IIC is derived by subtracting the IIC of the nominal 6’’ bare concrete from the IIC of the various tested assemblies. The higher the Delta IIC, the higher the performance level. Delta IIC is derived from ASTM E2179, the Standard Test Method for laboratory measurement of the effectiveness of floor coverings in reducing impact sound transmission through concrete floors.

• FIIC, Field Impact Insulation Class, refers to testing procedures conducted in the field following ASTM E1007 and E989. The FIIC test is conducted by setting up testing equipment in the field where sound is not as controllable.

• AIIC, Apparent Impact Insulation Class, refers to testing procedures conducted in the field following ASTM E1007. For these metrics, sound power from associated support structures are attributed to the floor-ceiling assembly. Because these are measures of the apparent performance of the nominally separating floor-ceiling, the receiving room shall be the space directly under the tapping machine.

Sound Transmission Class (STC)

STC, which stands for Sound Transmission Class, is a rating of how well a building partition attenuates airborne sound (such as voices, radio, or television) in the context of multi-family facilities. STC is measured and stated in accordance with ASTM C634, and tested via ASTM E90, E336, and E596. STC values are influenced by the solid mass of the structure, but are also dependent on isolation and resilience within the structure.

• FSTC, Field Sound Transmission Class, refers to testing procedures conducted in the field following ASTM E1007 and E989. The FSTC test is conducted by setting up testing equipment in the field where sound is not as controllable.

For more information on Sound Ratings, selecting a sound device and installation method that meets the needs of your installation, please refer to the NWFA Installation Guide.

Moisture Testing

Flooring installers must know the MC of the wood flooring, as well as the subfloor. Refer to NWFA Installation Guidelines for Moisture Testing for Wood Flooring, Wood Subfloors and Concrete Slabs. Never use a vapor retarder over subfloor to remedy a known moisture condition, and never install a wood floor over a known moisture condition.

Acceptable Vapor Retarders

The 2012 IBC defines three classes of vapor retarders:

Class I 0.1 perm or less

Class II 0.1 – 1.0 perm

Class III 1.0 – 10 perm

Over Wood Subfloors

When installing wood flooring over a wood subfloor, identify if the space directly below the flooring is a conditioned space or an unconditioned space:

Conditioned Space

Conditioned space is an area or room within the building that is intentionally heated or cooled, and humidified or dehumidified, to be maintained at the same conditions as the living/interior space either for the comfort of occupants, or for preserving temperature and humidity-sensitive goods.

• No vapor retarder is necessary over the wood subfloor and under the wood floor when the flooring is being installed over a conditioned space that is maintained at the same temperature and humidity as the living space directly above.

• No vapor retarder should be installed over the wood subfloor and under the wood floor, where a Class I or Class II vapor retarder has been installed on the underside of the joists.

Unconditioned Space

Unconditioned space refers to exterior space or spaces within the shell of a building that is neither directly nor indirectly heated, cooled, humidified, nor dehumidified.

• A Class II vapor retarder (sheet-good or liquid-applied) may be used on wood subfloors over unconditioned spaces to slow the rate at which potential moisture-laden air moves through the assembly and into the wood flooring, unless otherwise directed by the flooring manufacturer.

Over Concrete Subfloors

Every concrete slab on- and below-grade should have a Class I vapor retarder installed directly beneath it, prohibiting the passage of ground moisture through the slab. If the vapor retarder

below the slab has been compromised or left out, moisture will be able to move freely through the slab and into the flooring system. Unfortunately, there is no way of knowing whether there is an

intact vapor retarder in place below the entire slab.

• Moisture test the concrete substrate in accordance with the most current ASTM standards, to align the moisture control system and installation method with the condition of the slab.

• Install a Class I impermeable vapor retarder when calcium chloride readings are greater than 3 pounds, relative humidity readings are greater than 80%, or calcium carbide readings are

greater than 2.5%.

• In on- and below-grade applications, due to the ever-changing moisture variability with a concrete slab, and the likelihood of sub-slab moisture barrier degradation over time, a Class I impermeable vapor retarder is always recommended.

Depending upon your installation method, the type of vapor retarder will vary. Refer to the NWFA Installation Guidelines for more information.

This Allwood Installation Instruction Manual is created based on the National Wood Flooring Association (NWFA) Installation Guidelines. These guidelines by NWFA are regularly reviewed by a committee of industry experts, offering industry-accepted standards for hardwood flooring techniques. Follow the most current NWFA Installation Guidelines if any of the instructions in this manual differ or conflict from the former. Contact your local distributor if you need a copy of the guidelines.

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