Bruce Westmoreland - Manual (Page 2)

III. SUBFLOOR/UNDERLAYMENT REQUIREMENTS
NOTE: Solid wood flooring can be fastened to most existing flooring products providing the subfloor/underlayment
materials meet or exceed the following requirements and the flooring materials can be penetrated with the fastener.
Laminated rosin paper or 15# builders felt (tarpaper) acts as a moisture retarder and may be used to reduce
movement caused by changes in subfloor moisture, thereby reducing cupping and warping. (This is especially helpful
over crawl spaces and basements) In addition, the use of these materials can give the flooring a more solid feeling,
reduce sound transfer, prevent noise caused by minor irregularities and debris, and make it easier to slide the wood
together across the surface of the subfloor. Craft paper may be used to make installation easier but DOES NOT serve
any other purpose.
Wood Subfloors and Underlayment
General: The wood subflooring materials must not exceed 13% moisture content. Measure moisture content of both
subfloor and wood flooring to determine proper moisture content with a reliable wood moisture meter. The difference
between the moisture content of the wood subfloor and the wood flooring must not exceed 4% for strip and 3% for
plank flooring. When installing parallel to the floor joists it may be necessary to stiffen the subfloor system by
installing an additional minimum of 3/8˝ (9.5 mm) approved underlayment. Applicable standards and
recommendations of the construction and materials industries must be met or exceeded.
Solid Wood Subfloors
• Minimum 3/4˝ (19 mm) thick with a maximum width of 6˝ (15 cm) installed at a 45˚ angle to the floor joists.
• Group 1 dense softwood (Pine, Larch, Douglas Fir, etc.) No 2 common, kiln dried with all board ends bearing on
joists.
NOTE: As flooring manufacturers we are unable to evaluate each engineered system. Spacing and spans as well as
their engineering methods are the responsibility of the builder, engineer, architect or consumer who is better able to
evaluate the expected result based on site-related conditions and performance. The general information provided
below describes common, non-engineered joist/subfloor systems. Engineered flooring systems may allow for wider
joist spacing and thinner subflooring materials.
Wood Structural Panel Subfloors and Underlayment (Non-engineered)
Structural panels/underlayment must be installed sealed side down. When used as a subfloor allow 1/8˝ (3.2 mm)
expansion space between each panel. If spacing is inadequate cut in with circular saw. Do not cut in expansion
space on tongue and groove panels.
• Plywood: Must be minimum CDX grade (exposure 1) and meet US Voluntary Product Standard PS1-95
performance standard or Canadian performance standard CAN/CSA 0325-0-92. The preferred thickness is 3/4˝ (19
mm) as a subfloor [minimum 5/8˝ (16 mm)] or 3/8˝ (9.5 mm) as underlayment
• Oriented Strand Board (OSB): Conforming to US Voluntary Product Standard PS2 or Canadian performance
standard CAN/CSA 0325-0-92 construction sheathing. Check underside of panel for codes. When used as a
subfloor the panels must be tongue and groove and installed sealed side down. Minimum thickness to be 23/32˝
(18.3 mm) thick when used as a subfloor or 3/8˝ (9.5 mm) as underlayment. Some board manufacturers
recommendations vary.
Concrete (Requires additional subfloor)
NOTE: We do not recommend solid hardwood flooring be installed directly to concrete without the addition of other
subflooring materials to which the flooring can be fastened. Some adhesive manufacturers have had substantial
success with direct glue applications using a variety of different adhesives and moisture retardant systems. Follow
the adhesive manufacturer’s recommendations and check their warranty coverage. We will not be responsible for
claims associated with direct glue applications of our solid hardwood flooring products since we neither make nor
recommend an adhesive for that purpose.
Concrete Moisture Tests
All concrete subfloors should be tested for moisture content. Visual checks
may not be reliable. Test several areas, especially near exterior and
plumbing walls.
The acceptable test method for subfloor moisture content is:
• Tramex Concrete Moisture Encounter Meter (Figure 2)
Moisture readings should not exceed 4.5 on the upper scale.
(Figure 2 shows an unacceptable reading of over 4.5).
Note: The following tests are required in commercial applications,
either or both tests are acceptable
• Calcium Chloride Test (ASTM F8691). The maximum moisture transfer
must not exceed 3 lbs./1000 sq. ft. in 24 hours with this test.
• RH Levels in Concrete Using In-situ Probes (ASTM F2170-02) should not exceed 75%.
“DRY” CONCRETE, AS DEFINED BY THESE TESTS CAN BE WET AT OTHER TIMES OF THE YEAR. THESE TESTS
DO NOT GUARANTEE A DRY SLAB. ALL NEW CONSTRUCTION CONCRETE SLABS SHOULD HAVE A MINIMUM
OF 6 MIL (10 MIL PREFERRED) POLY FILM MOISTURE BARRIER BETWEEN THE GROUND AND THE CONCRETE.
Subfloor Systems
Bonded to Concrete
Concrete must be of high compressive strength, 3000 PSI or better. Install a suitable moisture retardant followed by
a plywood subfloor with a minimum thickness of 3/4˝ (19 mm). Allow 1/2˝ (13 mm) expansion space around all vertical
objects and 1/8˝ between all flooring panels. In general smaller panels [less than 4´ x 8´ (1.2 x 2.4 m)] oriented at 45
degrees (preferred) offer better results. The panel must be properly attached to the subfloor using a minimum of one
fastener per square foot and more if necessary. Use pneumatic or powder actuated fasteners. Do not hand nail the
subfloor with concrete nails. Install a moisture retardant barrier with joints lapped 6˝ (15 cm) and begin installation of
flooring using 1-1/2˝ (4 cm) fasteners.
Floating Subfloor
Install a suitable moisture retardant followed by a plywood subfloor with a minimum of 3/8˝ (9.5 mm) [1/2˝ (13 mm)
preferred]. Allow 1/2˝ (13 mm) expansion space around all vertical objects and 1/8˝ between all flooring panels. Install a
second layer of plywood of the same thickness at a right angle to the previous panels, offsetting the joints 2´ (61 cm).
Staple together with staples that will not penetrate the first layer of subfloor with a crown width of 3/8˝ (9.5 mm) or more.
Install a moisture retardant barrier with joints lapped 6˝ (15 cm) and begin installation of flooring.
Screeds/Sleepers
Note: Solid wood flooring exceeding 4˝ (10 cm) in width cannot be installed directly to screeds. Screeds should be
installed 8˝-16˝ (20-41 cm) apart in rivers of adhesive at right angles to the flooring to be installed. Do not begin
installation until all adhesives are properly cured. Install moisture retardant over the screeds prior to installation of the
flooring.
IV. INSTALLING THE FLOOR
General Information for “Blind Fastening” Machines
• Avoid striking the edge of prefinished products with the fastener’s
mallet. Edge crushing can occur causing unsightly cracks and
splinters. Use a protective foot attachment to prevent edge bruising
and finish damage.
• Improper adapter plates and air pressure settings can cause severe
damage to the wood flooring and reduce performance (Figure 3).
Always us an in-line regulator to control air pressure to the machine.
Set pressure at 70-75 PSI to begin with and adjust until proper fastener
setting occurs.
General Installation Tips
• Floor should be installed from several cartons at the same time to ensure
good color and shade mixture.
• Be attentive to staggering the ends of boards at least 4˝-6˝ (10-15 cm),
when possible, in adjacent rows (Figure 4). This will help ensure a more
favorable overall appearance of the floor.
• Spans exceeding 20´ (6 m) in wood flooring width in areas of high
humidity may require the addition of internal or field expansion. This can
be accomplished by using spacers, such as small washers, every 10-20
rows inserted above the tongue and removed after several adjoining rows
have been fastened. Do not leave spacers in for more than two hours.
• Preselect and set aside boards that blend best with all floor mounted
moldings to assure a uniform final appearance. These boards will be installed adjoining the moldings.
• When installing products of uniform length begin the rows with starter boards cut to various lengths. Avoid
staggering the rows uniformly to prevent stair-stepping. Boards cut from the opposite end of the row may be used
for the next starter boards.
• Always allow a minimum 3/4˝ (19 mm) expansion around all vertical obstructions.
• Always use a protective foot on the fastening machine to prevent mallet damage and edge bruising.
NOTE: SPECIAL INSTRUCTIONS FOR PLANK FLOORING
Seasonal distortion (shrinkage/cupping) in wide width flooring [4˝ (10 cm) and
over] may be reduced by gluing the flooring to the subfloor, in addition to the
use of mechanical fasteners. The installer should be reminded that adhesives
used for this purpose will not perform their function when used in conjunction
with a moisture retardant. Glue assisted applications will not be satisfactory
without direct contact with the subfloor. The glue should be a premium grade
urethane construction adhesive applied in a serpentine pattern to the back of
the wood as noted in Figure 5.
STEP 1: Doorway and Wall Preparation (All Installations)
• Undercut door casings and jambs. Remove any existing base, shoe mold or
doorway thresholds. These items can be replaced after installation. All door
casings and jambs should be undercut to avoid difficult scribe cuts
(Figure 6).
• Install the moisture retardant (if used) parallel to the flooring. Overlap
the rows 6˝ (15 cm). Overlap (top) should be on the same side as the
groove of the flooring so that the wood will slide smoothly into place.
Staple the moisture retardant material as necessary to prevent
excessive movement.
STEP 2: Establish a Starting Point (All Installations)
• Installation parallel to the longest wall is recommended for best visual
effects; however, the floor should be installed perpendicular to the
flooring joists unless subfloor has been reinforced to reduce subfloor
sagging.
• When possible, always begin layout or installation from the straightest
wall, generally an outside wall.
• In at least two places at least 18˝ (46 cm) from the corner, measure out
equal distance from the starting wall (Figure 7) the face width of the
starter board plus 1˝ (2.5 cm) (do not include the width of the tongue in
this measurement. Mark these points and snap a chalk line through
them. This measurement allows for the required 3/4˝ (19 mm)
expansion and the width of the tongue.
STEP 3: Installing First and Second Rows
(Starting from Wall)
• Use the longest, straightest boards available for the first two rows. For
random and alternate width products, use the widest plank for the first
row. Align tongue of first row on chalk line. The groove should be facing
the starting wall.
• Use a pneumatic finish nailer to face-nail the groove side 1/2˝ (13 mm)
from the edge at 6˝ (15 cm) intervals and 1˝-3˝ (2.5-7.6 cm) from each
end. Then, blind nail using finishing gun held at a 45° angle nail down
through the nailing “pocket” on top of the tongue every 6˝-8˝ (15-20 cm)
(Figure 8).
• If using finish nails, pre-drill the nail holes with a 1/32˝ (1 mm) bit
approximately 1/2˝ (13 mm) from back (groove) edge, 1˝-3˝ (2.5-7.6 cm)
from each end, and at 6˝ (15 cm) intervals. Pre-drill at the same intervals at a 45° angle down through the nailing
“pocket” on top of the tongue. Face-nail the groove side where pre-drilled. When complete blind-nail at a 45° angle
through the tongue of the first row. Fasten using 6 or 8d finish nails. Countersink nails to ensure flush engagement
of groove. Avoid bruising the wood by using a nail set to countersink the nails.
• Continue blind-nailing using this method with following rows until blind nailer can be used.
STEP 2 - 3 Alternative: Installing First & Second Rows
(Starting from Center)
• Snap a chalk line down the center of the room.
• Install a sacrificial row that extends the entire length of the room on the centerline.
• Install three rows of flooring.
• Remove the sacrificial row and insert wood glue in the groove followed by a slip tongue (spline) in the exposed
groove.
• Always glue and nail the slip tongue in place.
• Installation can now continue from the center in both directions.
STEP 4: Dry Lay (Racking) the Floor
• “Dry” lay (rack) materials to cover approximately 2/3 of the room. Begin dry laying (racking) approximately 6˝ (15
cm) from the edge of the previously installed rows. Avoid pulling boards too tightly together on the sides, as they
must move freely when fastening begins.
• Do not cut final board until row has been installed. Cutting the board in advance may result in a board that is too
short.
• Visually inspect flooring, setting aside boards that need to have natural character flaws cut out.
• Use these boards for starting and finishing row after objectionable characteristics have been removed.
STEP 5: Installing the Floor
• Make certain that you use the pre-matched wood and molding sets at their appropriate locations
• Use the blind nailer to fasten a sacrificial board to the floor. Check for surface damage, air pressure setting, tongue
damage, etc. before proceeding. Make all adjustments and corrections before installation begins. Once proper
adjustments have been made, remove and destroy the board.
• Begin installation with several rows at a time, fastening each board with at least two fasteners 1˝-3˝ (2.5-7.5 cm)
from the ends. Use the fastener schedule (Figure 9) for proper spacing based on board width. End-joints of
adjacent rows should be staggered 4˝-6˝ (10-15 cm) when possible to ensure a more favorable overall appearance.
2
Figure 2
Figure 3
Too Low Correct Too High
BACK
OF PLANK
ADHESIVE
Figure 6
Figure 7
multiple of width
of product + 3/4″
(6 mm) expansion
chalk line
1st row 1st row
2nd row
face nail every
6˝ (15 cm)
blind nail into
tongue every
6˝-8˝ (15-20 cm)
tongue
Figure 8
Figure 5
4 –6
(10–15 cm)
Figure 4
Preferred Alignment