Mark uneven areas with a pencil. Mix the leveling compound as instructed by the manufacturer. Using a flat-edged trowel, apply the floor leveling compound. Fill in all dips and uneven spots in the subfloor.
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. Subfloors must not slope more than ½ inch per 6 feet (25 mm per 1.8 m)
Pour the liquid-like floor leveler onto the subfloor and smooth it out with a trowel. Gravity will help it settle into the low areas. Remove any excess floor leveler and feather it around the edges so it blends with the rest of the floor. Let the floor leveler dry overnight or as indicated by the manufacturer.
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. When mixed with water, the compound settles into low areas and dries to a smooth, level surface.
If you've got a plywood subfloor, like many buildings do, you can leave it in place and apply self-leveling concrete directly on top of it.
What are the costs to fix sagging floors and subfloors? 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.
When a subfloor starts to creak and the nearby floors are uneven, sunken, or sagging, it's likely time for a replacement. Repairing a damaged subfloor has a typical price range of $300 to $2,500.
Most flooring manufacturers recommend a variation of no more than 3/16 inch over a 10-foot span. Floor leveling is a relatively easy DIY project, although some subfloors with rot, insect damage, or structural issues may require professional attention.
Uneven subfloors are a common issue. I have heard from installers that some homeowners do not want to pay for getting the subfloor to within flatness tolerances, which can get expensive so they continue the job without taking this critical step.
The best flooring for uneven floors due to its attractiveness and durability is epoxy, which can also be designed to mimic a wide variety of appearances. Not only will epoxy finish out the floor, but it'll also even it out.
The easiest way is to use a self-leveling compound, also called liquid floor underlayment or floor resurfacer, within sections of level-cut rails. The material flows out like thick syrup, then hardens into a smooth, perfectly level surface, sometimes in less than an hour.
There are several different causes of an uneven floor. It's possible that the subfloor is warped and loose, but it could also mean that the floor joists may be warped or split. There's also a chance that the foundation or support walls may have settled over time, causing an uneven floor.
What Causes Uneven Floors? The term “uneven floors” is used to describe any floor surface that sags, bounces, buckles or slopes. As mentioned above, it's common to find slanted floors in a house more than 15 years old due to the home's foundation shifting over time.
Mortars cannot be used to level or patch a floor – ever! The materials used in mortars render the product unstable once the thickness exceeds the manufacturers' recommended maximum thickness. Most thin-set mortars have a maximum thickness of 1/4" (6 mm) and medium-bed mortars have a maximum of 1/2" (12 mm).
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.
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.
In general, homeowners insurance covers subfloor water damage. However, it must be caused by one of the perils listed in your insurance policy. If you have an HO-2 policy, your building, including the floor, is protected against various threats, such as a ruptured water heater or pipe.
Replacing a subfloor can sometimes escalate into a bigger project, but there are some cases where you can remove parts of the subfloor without having to take down the wall.
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.
Uneven floors are most common in old homes because the home's foundation shifts over time. For example, it may take about 15-20 years for a foundation to shift and the floors to become uneven.
The degree to which your floor slopes or sags indicates whether or not you have reason for concern. Typically, floors that slope 1-1/2 inches or less in 20 feet is not a problem. Floors that sag 2 inches or more in 20 feet, though, are a cause for concern.
It costs approximately $3 to $10 per square foot to replace a subfloor, depending on the material you choose. Consider choosing a moisture-proof subfloor for bathrooms or basements. If you're installing underfloor radiant heating, you'll need a special type of subflooring called Warmboard.