A subfloor needs to be clean, dry, level and structurally sound. Use a level to determine if the floor is level within 3/16-inch change per 10 feet. Mark any high or low spots with a pencil or marker. If you're gluing the new floor to the subfloor, use a sander to remove oil, wax, paint, adhesives or other materials.
Put a level on the floor and see if it slopes somewhere. If it does, you mark the level height all around, mix the leveling compound and pour it out, and rake it around. If the floor is level but has a set of drops or pool points, draw around those pond areas with a permanent marker.
To check for small high or low spots that may not even be visible, place a long level or straight pipe on the subfloor. Move it around to different areas and mark any high or low spots you find with a pencil or marker. Most floors will have at least some slight variations.
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.
You can use a self leveling thin set, or you can just install the subfloor. Just make sure that as you're framing the subfloor, you measure frequently to keep a uniform height, and allow the use of shims (which will help with adjustment). If you can get access to one, a laser level is super handy.
Liquid Leveler is still the best option
As Steller Floors have grown in popularity, we have heard of many, many ways to level subfloors but by far, the best way is by using liquid floor levelling compound. It is the fastest, easiest, most cost-effective solution in the bunch.
For concrete slabs: If there are only a few problem areas in the concrete, you can mechanically flatten them by grinding, bead-blasting, abrading, or using a patching compound. If the entire slab is uneven, you may have to use a self-leveling concrete compound to smooth it out.
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.
The acceptable tolerance for subfloor unevenness for laminate flooring is typically 3/16 inch over a 10-foot span. If any areas exceed this tolerance, they will need to be addressed before proceeding with the installation.
Though floor sloping is a common problem, it isn't purely a cosmetic problem. Floor sloping can indicate that there's a much more severe issue at hand. Sloping floors can signify that there is significant structural damage to a home's foundation, warped floor joists, or water damage requiring foundation repair.
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.
Check with the straightedge in different positions. Of course, you could also do this by eye. However, checking the subfloor with a long metal ruler gives the necessary insight into the actual condition of the floor. The straightedge makes any potentially hollow areas visible.
Moderate damage: For areas with uneven joists or minor subfloor issues, repairs could cost between $1,000 and $5,000, depending on the extent of the damage and the repair technique used. Major structural repairs: If the problem stems from foundation issues or severely damaged joists, costs can climb significantly.
If you're experiencing uneven flooring, fear not! With the right techniques and a little bit of effort, you can easily level your floor using plywood. This blog will provide a step-by-step guide on leveling a floor with plywood, ensuring a welcoming and well-designed space.
Most flooring manufacturers specify a flatness tolerance, typically 1/8” over a 6-foot span, or 3/16” over 10 feet. However, tolerances can be much tighter especially for industrial and healthcare applications. In the level areas, we needed to achieve a near-zero deviation—less than 1/8” over 10 feet.
Place the Level on the Floor - Start in one corner of the room and place your level flat on the floor. Check the bubble in the centre of the label. If it sits perfectly between the lines, your floor is level in that section. Repeat the Process Across the Room - Move your level across different sections of the room.
If your subfloors dip, sag, slope, have irregularities, and are uneven, your flooring will not be flat or even, too.
In general, if a floor slopes ½ inch to 1 inch for every 20 feet of the floor, it may require you to watch the situation, but it may not be a big concern. Sloping or sagging floors of more than 2 inches will indicate a problem. Sometimes, original builders slope the floor to allow for drainage.
Before you put down your new floors, underlayment is a great way to ensure your subfloor will be level.
To treat low spots on concrete and mortar subfloors, use a leveling compound and a trowel. Wood subfloors need to be solid and free of rot or damage. If some of the plywood or wood is damaged, you might need to replace the entire piece. If your floor has any low spots, use a self-leveler.
So it's crucial to do some preparation before you start. Even for a DIY novice, levelling a floor is a relatively easy job. You just need a little background knowledge and the right equipment. And to help, we've also created this simple step-by-step guide.
A good rule of thumb to estimate is that a self leveling concrete floor will cost around $600-850 per 100 square feet.
The best solution for uneven flooring is a latex floor screed. It is a powder mix that you can pour down on the uneven flooring and let it settle down by itself. Then you can use the wooden screen to even out the floor. A self-levelling compound like latex floor screed is excellent for a wide range of flooring.
One way to install flooring on uneven floors is to choose a type of flooring that is naturally flexible. This makes carpet one of the most ideal options: it's cheap, easy to install, and very attractive. For only slightly uneven flooring, sturdy materials such as luxury vinyl plank can also be used for full coverage.