Installation InstructionEngineered Wood Flooring (with T/G)

This is only a guide. Follow the National Wood Flooring Association’s installation guidelines and recommendations when installing FERMA branded products.


A. General Information:

  • It is recommended that three methods of installation for the engineered flooring: staple down, fully spread glue down and float (only applied to 4 ¾” or 5” or wider planks). The two basic acceptable sub-floors are wood (plywood, OSB) and concrete. These will be addressed separately. It is also recommended that installation should be made by experienced professionals who subscribe to installation standards as set forth by NOFMA, NWFA.
  • It is not recommended installing engineered flooring over particle board, MDF, wafer board, masonite or luan underlayment or and radiant heat system.
  • Engineered flooring is machined to exacting tolerances. Its use is limited to on-grade or above grade applications. Full bath installations are not recommended because of moisture issues encountered there.
  • Use of approved products during installation as described in this installation instruction is required to validate all warranty.
  • Sawing, sanding or machining of wood flooring can cause respiratory, eye and skin irritation. The International Agency for Research on Cancer has classified wood dust as a nasal carcinogenic in humans. If using power tools, a dust collector is recommended, as is a dust masks NIOSH approved. Avoid contact with the eyes or skin when in proximity to wood dust. Use of a protective device for the eyes is also recommended.

B. Responsibilities of Purchaser/Installer:

  • The purchaser/installer should inspect all of the flooring before installation. Being a natural product, hardwood rarely will be perfect. Industry standards of manufacture allow for grading deficiencies up to 5%. This 5% may be composed of natural or manufacturing deficiencies. The purchaser/installer should carefully examine the flooring for color quality and finish. DO NOT INSTALL IF THE PRODUCT IS NOT ACCEPTABLE. Seller should be contacted immediately. Installation of flooring denotes installer and owner accepts the materials, even if owner is absent at time of installation.
  • It is noted that stain-putty filler is an accepted part of the installation procedure throughout the industry.
  • It is the purchaser/installer’s responsibility to determine the suitability of the job site environment and sub-surfaces involved. Installation must follow recommendations of the construction industry and the material’s manufacturer as well as local codes. Reference is made to NWFA requirement for minimum job site conditions and substrate requirements.
  • FERMA declines any responsibility for job failure or non-acceptability from or associated with sub-floor/substrates or job site environmental deficiencies.

C. Pre-Installation:

  • Unlike unfinished flooring, extra caution is needed during installation of pre-finished wood flooring to prevent scratch and damage.
  • Engineered wood flooring must be installed on grade or above grade. Below grade installation is not recommended for FERMA engineered wood flooring.
  • The building, where the installation takes place should be completed to an environmental control level, whereas doors and windows are in place and paint and masonry work is dry.
  • Basements and crawlspaces must be dry and well ventilated. Crawl spaces must be a minimum of 24” from the ground to bottom of joists. A ground cover of 6-8mil poly should cover the soil in the crawlspace 100%. Seams lapped at least 12” and sealed. Edges should be lapped up the perimeter walls 3”-6” to divert moisture to the outside. This vapor barrier is REQUIRED.
  • Perimeter venting is necessary to provide for cross ventilation. Minimum combined venting should be equal to at least 1.5% square feet of the crawlspace or exceed where applicable. Local codes prevail. No dead walls allowed impeding cross flow of air movement.
  • The installation site should have at or near environmental living conditions 68F – 72F temperature, 40%-60% relative humidity, prior to, during installation and or until site is occupied. These conditions will allow for acclimation of wood to the proper environmental conditions. Moisture testing is still necessary.
  • Exterior grading must drop at least 3” in 10 feet or according to local codes. All gutters and downspouts must be in place and divert run-off away from structure.
  • Flooring must be stored in a clear dry environment. Do not deliver materials to a site that is not environmentally controlled. This means building must be closed in, windows and doors on, all wet work complete, heat air or equivalent environmental controls functioning, temporarily or permanently. Moisture control is necessary for at least 7 days prior to delivery.
  • The wood sub-floor must NOT exceed 12% moisture content. The difference in moisture content between the sub-floor and wood flooring must NOT exceed 4%, preferably 2% for exotic and larger plank. A reliable moisture meter should be used to measure and determine accurate moisture contents.
  • Acclimation time for engineered wood flooring is determined by the moisture content of the sub-floor and the wood at time of delivery, but at least 5-7 days acclimation is needed prior to installation. It is to allow wood flooring to acclimate to sub-floor with no more than 4% difference in moisture contents (2% is preferred).
  • Exotic woods such as Brazilian Cherry (JATOBA) may need longer acclimation period.

D. Installation over Wood or Ply-Wood Sub-floors:

  • Sub-floor should be flat within 1/8” in 6 feet or 3/16” in 10 feet. Wood sub-floors must be clean, free of paint, sealers, adhesives, wax or any other debris.
  • If installing over existing hardwood floor, a layer of 5/8 plywood or OSB is recommended before proceeding. Plywood sub-floor should meet APA-PS2-92 standards. Plywood should be tongue and groove. Plywood must be minimum 3/4”CDX.
  • Oriented strand board, OSB, when used must be tongue and groove, installed sealed side down, minimum thickness 23/32”, must conform to US VOL product std PS2-92. OSB must be tongue and groove, exposure 1, preferably exterior grade. It must meet US VOL STD PSI-95 performance STD for 16” on center joist system.
  • Particle board or wafer board are not acceptable as a sub-floor.
  • Engineered flooring is manufactured at 6-9% moisture content. The tolerance between new engineered flooring and sub floor should not exceed 4% point’s maximum, preferably 2% points. All wet work should be completed before delivery of flooring. This includes but is not limited to, ceramic, masonry, painting, drywall work, patching, plaster work... Moisture content should not exceed 12% in the sub-floor.
  • Check floor substrate for deflection. The formula in general is L/360. L is the length of the unsupported span in inches. For example, a 10 feet span, L is 120 (10feet x 12inches per foot,) so 120/360 is 1/3. The maximum deflection of this 10 feet span is 1/3". Nail or secure any loose areas. Any excess vertical movement must be corrected as this will affect long term performance. As manufacturer of specialty flooring, it is not able to evaluate each and every residence’s engineered structural system. Spacing span lengths, sub-floor thicknesses as well as their engineering methods are the responsibility of the builder, engineer, architect or consumer, who are better positioned to evaluate the expected end result based on the site related conditions.
  • When staple method is used, a layer of 15lb. roofing felt is required between sub-floor and engineered flooring. Fastener should be used 4”-6” apart or more as needed to secure product. Fasten each end 1-3” from end. Gluing ends of tongue and groove to minimize shrinkage. Be sure to experiment on a scrap piece first and adjust the compressor setting to avoid damaging the tongue.
  • The recommended adhesive is FERMA DT-9200, with a recommended trowel size of 3/16" x 3/16" x 3/16"
    Square notch, or DriTac equivalents. If using equivalent use the Adhesive Manufacturers  specified trowel size for floor type being installed. Always check for proper bond. Glued down flooring must have a minimum 90% coverage preferably 100%. Pull up occasional boards and observe whether proper coverage is followed.
  • H Joints should be avoided. Ends should be staggered with at least 6” from preceding joint. Avoid a conspicuous stair step pattern. This helps to promote a pleasing over all appearance. Franklin TiteBond tongue and groove flooring glue #2104, or equivalents applied to end joints helps prevent longitudinal shrinkage. If using 3M blue tape to hold pieces in place, it must be removed within 24 hours. If left on longer it may affect the finish.

E. Installation over Concrete:

  • Engineered flooring could be glued on concrete, or installed with floating method, but it is only applied to 4 ¾”, 5” or wider planks.
  • Concrete must be clean, free of wax, adhesives, anti freeze chemicals, paint, patching compound, curing compounds or sealers, admixtures that are hygroscopic. If in doubt, do not install.
  • Concrete testing on slab 30 days old is the minimum time frame allowable. Less than 30 days old is not a reliable indicator. Concrete must be a minimum of 60 days old before flooring can be installed. It may be necessary to test for moisture multiple times or until acceptable.
  • Some self leveling cement compound used to correct concrete floor may have shorter curing time. Always check with the manufacture of the self leveling cement before proceeding with installation.
  • Concrete sub-floor must be flat to 1/8” in 6ft or 3/16” in 10 ft. Concrete may have to be shot blasted, scarified, or ground down until acceptable.
  • Moisture testing is necessary by concrete moisture meter or calcium chloride test.
  • Moisture meters are used to qualify moisture content of bamboo flooring, sub-floor, and concrete slab. Installer has the choice of many manufacturers of professional meters. Reading is not to exceed 4.5 on the meter scale. The use of calcium chloride test is also acceptable. Moisture emissions are not to exceed 3lbs per 1000sf. in a 24 hour time period.
  • PH testing is also recommended. A Ph factor of 5-9 is acceptable. 7 is neutral, above 9 requires corrective action. A high Ph factor may affect adhesive stability. Concrete must be at least 30 days old before moisture content testing takes placing.
  • Acoustic concrete and light weight concrete – Installer must check with concrete manufacturer for product compatibilities and any special needs to be addressed concerning installation/performance. FERMA does not accept responsibility for any problems resulting from failure to follow concrete/gypsum manufacturer’s recommendations.
  • The recommended adhesive is FERMA DT-9200, with a recommended trowel size of 3/16" x 3/16" x 3/16"
    Square notch. If using equivalent, use the Adhesive Manufacturers  specified trowel size for floor type being installed. Always check for proper bond. Glued down flooring must have a minimum 90% coverage preferably 100%. Pull up occasional boards and observe whether proper coverage is followed.
  • H Joints should be avoided. Ends should be staggered with at least 6” from preceding joint. Avoid a conspicuous stair step pattern. This helps to promote a pleasing over all appearance.  Franklin TiteBond tongue and groove flooring glue #2104, or equivalents applied to end joints helps prevent longitudinal shrinkage. If using 3M blue tape to hold pieces in place, it must be removed within 24 hours. If left on longer it may affect the finish.
  • If using floating method, the flooring could be floated by gluing tongue and groove. Floating is attached to the flooring itself and not to the sub-floor. It is installed over various types of cushion underlayment. This method is suitable with any sub-floor but only wider products should be considered for floating. This method involves gluing the tongue and groove joints of engineered flooring together over an underlay. The recommended adhesive is Franklin TiteBond tongue and groove flooring glue #2104, or  equivalents Also, some engineered flooring is also available for being floated by locking system. The installation method of floating by locking system could be referred to installation instruction of laminate flooring.
  • Underlayment with a polyethylene film sheeting, generally serves for protecting engineered flooring from moisture damage, adds acoustical dampening and stability. If using floating method over concrete, it should be placed on all concrete sub-floors prior to the installation. Roll the underlayment out over the concrete sub-floor, overlap the edges and use duck tape to keep in place and ensure a waterproof seal. Overlapping will prevent any moisture from seeping through the edges. Also be sure to place the underlayment all the way to the wall and slightly up the wall to ensure a good seal. Do not use masking tape instead of duck tape as it makes a noise when walked on and is not waterproof.

F. Molding:

Finish installations with following choices of moldings that will enhance the appearance of any installation. Refer to the illustrations and descriptions below for the proper use of each molding.

Molding / Trim


G. Further Information:

FERMA FLOORING is a member of National Wood Flooring Association (NWFA). FERMA recommends installation by experienced professionals who subscribe to installation standards as set forth by NOFMA, NWFA. For further information about the installation of engineered wood flooring, please refer to related instruction by NWFA as follows:

ENGINEERED PLANK INSTALLATION:
http://www.nwfa.org/member/pdf/InstallG/Chap8.pdf    

For more technical information about the installation, please also refer to other associated instructions by NWFA as follow:

JOBSITE CHECKLIST:
http://www.nwfa.org/member/pdf/InstallG/AppenM.pdf

JOBSITE CONDITIONS:
http://www.nwfa.org/member/pdf/InstallG/Chap1.PDF

ACCLIMATION:
http://www.nwfa.org/member/pdf/InstallG/Chap2.PDF

MOISTURE TESTING:
http://www.nwfa.org/member/pdf/InstallG/Chap3.PDF

CONCRETE SUBFLOOR GUIDELINES...
http://www.nwfa.org/member/pdf/InstallG/Chap5.pdf

INSTALLATION OVER EXISTING FLOORS:
http://www.nwfa.org/member/pdf/InstallG/Chap10.pdf

GLOSSARY OF WOOD FLOORING TERMS:
http://www.nwfa.org/member/pdf/InstallG/Glossary.pdf