Materials for the underlayment
What is it that determines the quality of an automobile – the body or the internal mechanics? Can we call any floor covering high quality, whether made of durable parquet, solid hardwood, or laminate, when it lies crooked, rattles when stepped on or smells of dampness? The “internal mechanics” of a floor covering are every bit as important as a powerful motor, a strong chassis, and high quality automatics are to an automobile.
One particularly important element which allows us to smooth out unevenness in the floor, isolate the hardwood flooring or laminate from moisture and sound, is called the underlayment. This is by no means a universal panacea, since an underlayment is installed only when the difference in height over two meters of floor is no greater than two mm per meter for hardwood flooring or three mm per meter for laminate. This is verified by the conformity of fit using a two-meter measuring rod. If the drop is greater, then before installing the underlayment, the “rough” floor must be further treated with special mixtures, evened out, dried and cleaned. Many people mistakenly believe that if the old flooring is left in place, you can avoid the use of an underlayment. Chipped up linoleum and cracking boards with deep fissures won’t save you from moisture under the floor and the threat of the odor of dampness in your home. It is best to leave a smooth concrete screed layer, a sewn-in waterproofing, or plywood attached with screws. Then, it’s time for the underlayment. The choice of materials is made by considering the following factors: the selected flooring material, the condition of the “rough” floor, the need for additional sound- and waterproofing, and the laying of subfloor heating. Mistakes in laying the underlayment lead to squeaking of the hardwood floorign, entry of construction and other debris underneath it, poor heat conduction, and many others.
Materials for the underlayment may include the following:
-Cork and composite materials on a cork base. Cork is the most natural material, and besides that it is extracted without causing significant harm to the tree, so it is very environmentally friendly. A cork underlayment helps fight fungus, does not contain volatile substances, gives greater soundproofing, and recovers its original shape following deformation. The thickness of a sheet of cork underlayment being from one-half to 10 or more millimeters, it smoothes out unevenness in the “rough” floor very well. The floor covering is laid out perpendicularly to the strips of cork underlayment.
On a cork base, ruberoid and cullulose form a composite material. Ruberoid or bitumen prevent the entry of moisture, while the cork particles provide micro-ventilation. An underlayment such as this does not require additional waterproofing, and absorbs sound excellently.
At the junction where the sheets of underlayment and the walls meet, adhesion is made by a broad ribbon of glue.
- Polyethylene and foams of various types. This underlayment is the simplest that you can choose: cheap, easily installed, excellent sound absorption, and protection from entry of moisture. Polyethylene is non-toxic. This is the optimal underlayment if you want to minimize time and expense in laying your floor and have decided to leave the old floor planking under the new floor.
- Tuplex or Penoroll composite materials. These have the maximum soundproofing and excellent moisture protection. The uppermost layer of the material is a thick moisture-proof polyethylene, and underneath that are polystyrol granules, and the bottom layer is a thin sheet of polyethylene which excludes moisture. To label it, the bottom layer carries the logotype of the company which manufactured it. The strip of material is fastened using a band of adhesive 20 cm along one side of the roll. Moisture which is conducted into the bottom polyethylene layer of the underlayment, after circulating among the polystyrol granules, exits through the gap joints. Since polystyrol is an excellent thermal conductor, this type of underlayment is optimal for installations with damp floors.
Considering the multitude of determining factors, the choice of underlayment is best entrusted to an experienced professional. It doesn’t pay to economize on it.