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DIY Steps for Installing an Insulated Basement Floor

Basement, Basement, Floors, Floors, Punch! April 10, 2010 Matt Weber


For the green-minded homeowner, another selling point of cork is the environmentally friendly nature of cork production. Cork is made by harvesting the outer bark of a Mediterranean tree called the Cork Oak that grows mainly in Portugal and Spain. The bark is stripped in such a way that it does not kill the tree. Only the bark is extracted, the tree stays alive, and a new layer of cork regrows, making it a renewable resource.

The Lisbon Cork floating floor should be laid on a clean, stable, flat, smooth and dry surface, and our subfloor system provided for this nicely. Without a subfloor, slopes of more than 1/4-inch over 6 feet must be leveled. You’ll also need to lay a moisture barrier of 2-millimeter plastic sheeting before laying the boards, overlapping the seams by about 8 inches. With any sort of engineered tongue-and-groove floor, it’s generally best to store the exposed planks indoors 48 hours before installing so they acclimate to the room’s temperature.

A hammer and pull bar helps to install the last panel in a row.

A hammer and pull bar helps to install the last panel in a row.

Measure the room to calculate the width of the last row. If the last row will be less than 3 inches wide, then use a table saw to rip the planks of the first row to a narrower width, which will translate to a thicker width for the last row. Even if you keep a full-width first row, you should still rip off the exposed tongue of the first row. All exposed tongues should be removed from the perimeter of the wall, including the ends of the boards that begin each row.

Rip the tongues off the cork panels where they meet the wall.

Rip the tongues off the cork panels where they meet the wall.

Also, measure to determine if the walls are square. The walls in this basement were not, which meant I had to rip certain boards to a smaller width than others to follow a slight curve in the wall.

Cork featuers a natural cellular appearance with rich character.

Cork featuers a natural cellular appearance with rich character.

Start in one corner of the room and install the panels from left to right, with the tongue sides facing the walls. Place 3/8-inch spacers against the wall along the perimeter of the entire floor to allow for expansion. The joints of the panels connect in tongue-and-groove style, but unlike the subfloor, the cork panels must be tilted to insert the tongue into the other panel’s mating groove. Join the long seam first, if possible. Tilt downward to pull the joint together, and then tap with a hammer and rubber block to lock it closed. Be careful with the block, because the soft cork material can be damaged by the hammer blows. Rather than hit the cork edge of the panel, use a notched block that misses the cork and only connects with the engineered wood core of the panel. A scrap block of mating cork flooring can also serve as a hammer block.

The tongue-and-groove joints of the cork floor connect easily.

The tongue-and-groove joints of the cork floor connect easily.

When beginning the second row, begin with a partial panel that staggers the joint at least six inches away from the preceding row. Repeat this pattern for the following rows so there is always a 6-inch minimum setback between the seams of adjoining rows. A table saw can make most of the rips and cross-cuts, although a jigsaw is a handy tool for making small cuts and notches in the floor boards.

The 1x3' size of the cork planks means the floor installs quickly because the larger the planks, the fewer there are to install.

The 1×3′ size of the cork planks means the floor installs quickly because the larger the planks, the fewer there are to install.