Apart from having a good sound base to install a laminate floor on to, you should also use the correct underlayment for the type of sub-floor, or base, and laminate flooring that you’re using. If you’re buying your laminate flooring online chances are you’ll also buy the underlayment online too. Once you know the type of underlayment you need it’s tempting to search around for the cheapest that you can get.

While shopping around for the best price is certainly something to do, it isn’t necessarily the best thing to buy the cheapest offer you see. The cheapest offer might not be made by the same manufacturer of the laminate floor itself. So, you’re advised to find the best price for that manufacturer’s product, which will be made to work the best with the flooring you’ve already bought.

Types of Underlayment for Laminate Floors

The type of underlayment you need will mainly vary according to the nature of the base that the laminate flooring is going to cover. If you have a concrete or mineral based sub-floor - a damp-proof membrane must be spread to act as barrier to moisture. Also, if the laminate floor is to be installed over an under-floor heating system, a damp proof membrane must be fitted. Other types of underlayment can then be added on top of the damp-proof membrane.

A foam underlay is often used to act as a leveler on a sub-floor with minor irregularities. Foam underlay is also effective for impact noise reduction. If you have need a damp proof membrane as well, you can purchase a special 'combination' underlayment, which is a foam that incorporates the damp proof membrane.

There is another ‘combination' underlay available, which combines the damp proof membrane with a sound insulator. The most common underlayment of laminate floors is simply known as ‘Board underlay’. This has all the properties required to reduce noise, make the laminate floor feel comfortable to walk on and provides a layer of insulation between the sub-floor and the laminate.

Preparing the Sub-floor

After the removal of any current floor covering from the floor base, it is important to ensure two things. First make sure that the base is flat and as level as possible and secondly that it is clean. If, what will become the sub-floor isn’t level; in the case of a solid base you should apply a leveling compound or in the case of a timber base - securely nail or screw down all the existing floor boards, then cover it with sheets of plywood, or similar, and screw them into place at 150mm centers.

If the original base, whether solid or timber, doesn’t need leveling or you must make sure no residue from any adhesive used with the previous floor covering is left behind. If possible remove any residue by scraping; if particularly stubborn a chemical solvent could also be used. Laminate wood flooring does not like excessive moisture and taking moisture prevention and inhibition steps at the underlayment stage will help the laminate floor to last longer.

Variations in moisture levels will cause a laminate floor to expand and contract, so the importance of preventing moisture rising through the underlayment cannot be stressed enough. Using a hygrometer you can measure the humidity of a room; if you get a reading above 65% you’ve got a potential moisture problem that could affect the performance of your laminated floor. You are strongly recommended to use one of the proprietary damp proof membrane sealing solutions as well as a damp-proof underlayment, before fitting the floor.

Photo by Ewen Roberts, Creative Commons Attribution License