Underlayment can help smooth things out, though, but the type you choose will vary depending on your specific reasoning for wanting an even subfloor. That can make choosing the right one for you rather tricky, so here's a quick guide that should lend a helping hand in getting the best underlayment for uneven subfloors.
Underlayment is typically used in a residential environment when, for example, a new wood or laminate floor is installed to help both level the substrate and raise it to finish evenly with another surface.
Fibreboard Underlay
This is the best choice for both types of flooring. It works to smooth uneven floors, reduces noise, and acts as a thermal barrier. If the subfloor is uneven, fibreboard works to even dips and dents you can't level out.
Underlayment can serve as a relatively simple fix to an uneven-subfloor. Keep in mind that in some circumstances you won't be able to use underlayment as underlayment should only be used for minor imperfections.
Forgetting to level the subfloor
The subfloor must be level before installing laminate flooring. If the subfloor is leveled, the laminate planks will not lay properly, causing uneven and unsightly floors. If the subfloor is not level, you can use a self-leveling compound to level it out.
One common option is using self-levelling compounds. This compound can be used on a concrete slab or a wood subfloor and can be effective with any dips on the floor. These self-levelling compounds are similar to concrete and typically come in large bags of powder.
Uneven floors in a house are usually a sign of a foundation problem, but not always.
No subfloor is perfectly level, but any signs of unevenness and high or low spots must be remedied. Please follow these requirements: Subfloor unevenness cannot be greater than 3/16 of an inch over a 10-foot span or 1/8 inch over a 6-foot span.
Ramp option for joining a carpet to a hard floor.
Another floor transition for uneven floors is the Compression Ramp. It is designed to join a carpet to a hard floorcovering, where there is a height difference of up to 5mm either way.
If mixed to the correct consistency, self leveling underlayment will spread out when poured onto a surface and seek its own level, lessening the labor required for a very thin coat. If the material is mixed too densely, it will not flow easily and will usually require additional troweling.
Underlayment is manufactured and meant to be used as only a single layer to allow your floor to be balanced and float properly. If you install any additional underlayment, the base for your flooring will end up being too soft and could jeopardize the integrity of the locking system.
Underlay thickness affects the feel of the carpet. A thick underlay, between 11 and 12mm, will give your carpet a cushioned, soft feel. However, a thinner underlay on the stairs may be easier to install. 9mm is ideal.
Self-leveling underlays will go on a little thicker than a trowel-on underlays. Self-leveling underlayments are a good choice because they can go over any substrate, are applied more thickly, are ready faster and can be covered more quickly.
If you want to raise the height of a floor, the cheapest and easiest way is to add a thick underlayment designed for the job. There are other options too like adding a framed wooden subfloor or floor leveling compound before installing new flooring.
There is such a thing as too much cushioning. A thick underlayment with low density will compress when weight is put on the flooring system, causing the flooring planks to bend and ultimately damage the locking mechanism.
To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion. Tongue-and-groove edges on many premium floor panels, such as Weyerhaeuser's Edge Gold® OSB panels, are designed to self-gap.
Rather than nails, screws are best to use for subfloors — these fasteners are convenient, easy to remove and capable of providing torque that nails lack. Because of their structure, screws can penetrate plywood more easily and improve the connection, whereas nails can weaken the plywood.
The typical costs for repairing sagging floors start at $1000 and can go up to $10,000, with the average rate being around $300 per square foot. But this can vary depending on the extent of the damage and materials needed to get the job done.
It can be heartbreaking, but sometimes your only real choice when dealing with foundation issues is to walk away. If the seller won't make repairs, the damage is too extensive or you can't wait for repairs to be completed, you may have no choice but to give up and find your next dream house.
Uneven floors are responsible for countless injury-causing falls each year. Whether it's a case of warped hardwood or bunched up carpeting, an uneven floor surface can spell danger for just about any unsuspecting person nearby.
On average, you are looking at about $3 – $5 per square foot. So, for a 100 square foot slab, it would generally cost between $300 and $500.
Use Self-Leveling Compound to Correct Subfloor
Wide sags and depressions in a floor sometimes can't be adequately bridged even by sheets of plywood, so it's best to fill these areas with self-leveling compound.
Fibreboard underlay
It helps smooth uneven floors, reduces noise and acts as an excellent thermal insulator. Not to mention, it's also the number one choice of underlay for laminate and wooden floors. If you have an uneven subfloor, the fibreboard will help even any dips and dents you can't level out.