Finished basements can add lots of useful square footage to a home for an apartment, playroom, work area or office. The trick is to control the effects of hydrostatic pressure of ground moisture coming through the concrete so that it doesn’t affect your laminate floor.
Defining a basement made for Swiss Krono laminate flooring
Here’s how we are defining a basement where Swiss Krono laminate flooring can be installed:
- A below-grade space with at least one concrete wall.
- The concrete-slab floor must have been poured with a poly sheet underneath it. This helps protect against changes in hydrostatic pressure and controls the curing process.
- The concrete-slab floor must be more than 90 days old (so that it’s adequately cured).
- It can have a “walk-out,” as onto a patio area or walkway.
- It cannot have a drain in the floor or a French drain along the inside of the perimeter of the floor. If you have drains in or around your floor, we don’t recommend a laminate floor.
Five common questions or concerns when installing a laminate floor
- If my basement already has an installed hard-surface floor, can I install Swiss Krono laminate flooring over the top of it?
The answer is a qualified “yes.” If the existing floor is hardwood, the answer is an unqualified “no.” If the existing floor is vinyl (as is pretty common) we want you to approach this installation as if it were a bare concrete floor. That means you’ll need to install a vapor barrier (more about that below) and cushion pad (unless your laminate plank already has an attached pad). Also remember that just because there may be an ugly sheet-vinyl floor already down and you want to cover it with a beautiful selection, don’t assume the floor is level or flat enough for a successful installation.
And remember, never install laminate flooring over carpet of any kind.
- What is the biggest concern when installing laminate flooring in basements?
Moisture! Moisture vapor flow can be forced up through the concrete floor due to hydrostatic pressure. Generally, below-grade conditions in most areas of the country mean that basements stay moist year-round and contribute to typical musty basement conditions. No two basements are alike and hydrostatic pressure conditions will vary. For example, even in arid regions there will be seasonal rainy periods that will alter the moisture-vapor flow up through the floor. Or your neighbor may install a swimming pool next door and, again, your basement’s moisture-vapor flow may be affected. As we’ve examined in as bathroom or kitchen installations, moisture is an enemy to just about any flooring, including laminate floors. Moisture encroachment in most basements (particularly those that are candidates for finishing) may not be obvious at all. But basement floors that have standing water, apparent moisture stains, or dampish areas are not good candidates. That’s why you should test your seemingly dry concrete basement floor before getting your heart set on installing a new Swiss Krono laminate floor over it.
- How do I make sure my basement floor is OK to be covered with a laminate floor?
There are four tests installers use to get a better understanding of the moisture in your basement concrete floor: the Matt test, the calcium-chloride test, the moisture-meter test and the relative-humidity test. Keep in mind that to properly test the conditions of your basement floor requires adequate planning ahead.
- Should I use topical moisture abatement applications to prevent concrete floor moisture?
When it comes to laminate flooring, we would say “no” in most cases. The moisture-abatement product must have zero volatile organic compounds (VOCs) to be acceptable underneath a Swiss Krono laminate floor. VOCs are the off-gassing of chemical compounds used in the manufacture of many household items, from paints and varnishes to wood products. Because the melamine backing on Swiss Krono laminate planks is so impermeable, the VOC gases produced by most moisture-abatement coatings will have nowhere to go. This means that trapped gas will build up under the vapor barrier of the floor and, over time, cause the floor to “pillow.”
- What “must have’s” should I consider when it comes to having a laminate floor in the basement?
- Always use a vapor barrier. A vapor barrier is the plastic film that stands between the concrete slab floor and your padding and laminate plank. Swiss Krono specifies that the vapor barrier for laminate floors must be 6-mil thick virgin polyester. Recycled film may not have the structural integrity you need. Remember, below-grade concrete walls are subject to hydrostatic pressure, too, therefore we want you to run the vapor barrier up the concrete wall about 4 inches in order to protect the exposed edge of planks next to it. Even with an expansion gap between the plank and the wall, the exposed edge could use the extra protection. A bead of 100% mildew-resistant silicone sealant would also be a good idea. After you’ve installed the baseboard, just cut the excess vapor barrier that may show above it away. Do not run the vapor barrier up a non-concrete wall (wood stick 2×4), such as a drywall surface.
- Invest in a dependable dehumidifier. As we stated earlier, every basement is different, so you may not need this. However, most basements are notoriously more humid than other rooms. Swiss Krono laminate flooring should always be in a climate-controlled environment where the humidity level stays below 75%. A dehumidifier can help ensure this.