KAYU Tongue & Groove Porch Flooring Installation Fundamentals

Kayu® Legendary Performance™

At Kayu® we offer only a few carefully chosen select species and are extremely meticulous when sourcing; careful of who we use as manufacturers and ensure quality control by having our own exclusive graders, inspecting every board.

Our Tropical Hardwood includes the very best hardwood species available, anywhere.  Exotically gorgeous, exceptionally durable and sustainable   harvested.  Compared to other commonly used woods, Kayu® is much superior in the vast majority of cases and in all comparisons we know of; outlasting and outperforming other materials. Our guideline here is to further enhance your Kayu® porch flooring appearance and performance for decades of enjoyment.

Fundamental Guidelines

We’ve outlined some fundamental guidelines to assist you with the process of installing your porch flooring, being mindful that many construction / installation details often vary from build to build.

All wood is subject to expansion and contraction as the moisture in the environment surrounding the wood changes. KAYU® hardwood is skillfully kiln-dried, board to board, resulting in highly consistent moisture content. Shrinkage is very limited, unlike air-dried boards.

Storage and Handling

Before installation and finishing, keep your KAYU® kiln-dried boards clean, dry and out of direct sunlight.  Acclimate to your project site by dry-storing 2 weeks prior to installation.  Do not store boards directly on the ground.  Be sure the bottom boards are well ventilated by placing the boards at least 4” off the ground and on top of blocks.  Do not cover boards with plastic or tarp during the acclimation period, this will trap moisture and cause stability issues.  Place a sheet of plywood on the top of the pile to shed any water.  Don not store the boards in an enclosed area  (this includes warehouses, garages).  Keep material dry until installation.

Essential.  If you store in an enclosed area, be sure it’s not heated and if possible open a door or window, again facilitating healthy air flow perfectly stabilizing your premium product to your local ambient air moisture content. please understand, all wood from anywhere should be treated this way, maximizing your products performance. Just a bit more care at this stage, the same as interior flooring will assure your floors performance among the very best of any flooring/porch product for decades. Now, please do not allow your material to later be rained on or lawn sprinkled just before installing


Prior to installation, seal the boards with a high-quality penetrating oil sealer or paint on all four sides. Sealing only one side will create an unbalanced moisture flow on the face and back, which under severe conditions or if not properly fastened, may lead to slight cupping.

In order to bring back the original color of the wood, a periodic cleaning and a new coat of finish will be necessary.  The rate at which maintenance is needed depends largely on; the degree of exposure to direct sunlight, climatic conditions, preference of wood color and the frequency at which any preservative treatments are applied. Once every year or two is the standard guideline for maintenance. However, we hear most often that an oiled Kayu® porch floor is re-oiled every 2-3 years.

Similar to all wood products, with time, KAYU® Hardwood will gradually fade to a silver-gray patina color.  If this is preferred, finish all four sides with a natural unpigmented finish and allow to weather naturally. In this state, maintenance will be as minimal and easy as any other flooring product on the market.


The end of each flooring board must be adequately supported by a joist. Install on a maximum joist spacing of 16” when boards are installed at a 90 degree angle to the joists. When installing on an angle, joist spacing should be on 12” centers. For best porch appearance and strength, end butted joints should be staggered to prevent direct alignment of the ends.


KAYU® Hardwood is skillfully kiln-dried for consistent application, board to board, using a highly sophisticated process of computer and operator controlled heat and humidity to adjust and regulate the drying of the lumber. Excessive moisture will cause the boards to expand slightly. Unlike air dried boards, shrinkage is very limited. Please refer to our website resource pdf. about why kiln-dried wood is far superior to air-dried.

KAYU® Hardwood does not shrink or expand end to end (unlike composite decking), therefore neatly trim ends and butt together.


Allowing adequate ventilation underneath the porch is extremely important for proper air flow to reduce the potential for cupping and surface checking. In high moisture areas, it is imperative to leave an expansion space; allowing the wood to expand and contract. In high moisture areas do not install the flooring tight, leave a 1/16” expansion space between each board.

Moisture underneath a non-ventilated floor will be absorbed by the bottom side of the board while the sun and wind will dry the top side of the board.  This unequal moisture content will cause cupping.

Construct the porch floor so that the surface is at least 2 feet above the ground.

Create a Slope underneath the porch; away from the building structure, posing no chance of standing water.

With close to ground applications, 60″ or less above the ground, a vapor barrier is necessary to prevent moisture from absorbing into the underside of the boards.

Build leaving a 1/2″ to 3/4″ expansion space at the wall of the house and use trim board to cover. This expansion space only needs to be on the two sides, allowing the boards to expand side by side. Our product does not expand or contrast length wise.


When KAYU®-Batu™ Tongue & Groove is being installed as a Soffit, we highly recommend a polyurethane adhesive in addition to fasteners due to the weight of the hardwood. Note: this step is not necessary with our KAYU®- Borneo Mahogany™ product which is the same as Douglas Fir.


Pilot holes are recommended to prevent splitting, especially on the end of the board; using stainless steel with 7d or 8d finish nails.  Blind nail through the tongue at about 45°.  The nail must penetrate the joists when face nailing within ¾” of the edge or end of the board.


KAYU® hardwood products are carefully selected species and manufactured to ensure the finest quality. However, all natural wood is subject to some minor expansion and contraction as the moisture in the environment surrounding the wood changes through the seasons. Careful attention to our installation instructions will be important to long term performance and enjoyment.