Have you ever thought about installing subfloors yourself? Your home’s hardwood flooring installation can give your home aesthetically beautiful and durable floors that will last many years to come if everything is installed correctly and well-maintained.
One crucial element to having a beautiful, long-lasting hardwood floor is a leveled subfloor. If your subfloors dip, sag, slope, have irregularities, and are uneven, your flooring will not be flat or even, too.
Luckily, you can follow these tips to make sure that your subfloors are level to help guarantee the success of your new floor installation.
What Are Plywood Subfloors?
A subfloor is part of a larger floor installation system. Subfloors are just one component of a floor installation that is actually made of a multi-layered surface based on the following four components: floors, underlayment, subfloors, and joists.
Floors
Floors are the uppermost layer of a multi-layered surface that a person can actually see, touch, and walk on. Materials commonly used for floors include real hardwood, engineered hardwood, laminate flooring, stone, and tile.
Have you decided on which flooring you are going to use in your home? If not, you may be interested in checking out these flooring options: hardwood flooring (acacia, bamboo, birch, eucalyptus, hevea, hickory, maple, walnut, and oak), waterproof flooring, pet-friendly flooring, etc.
Underlayment
Underlayment is a layer of acoustical foam, granulated rubber, or cork placed between the floor and subfloor in order to provide sound absorption. Plastic sheeting is commonly attached to the bottom side of the underlayment to provide a moisture barrier between the flooring and the subfloor.
Have you ever heard of the product “Underlayment for Hardwood Floors”? It is 3mm thick and comes with 100 square feet of moisture-resistant foam underlayment. This underlayment supports a flooring installation system by offering sound absorption with its moisture barrier that protects your floor, is non-allergenic, and is convenient to install.
Subfloors
Subfloors are the base of the floor system on which hardwood flooring is installed. And, while various materials are used for subfloors (i.e., plywood, oriented strand board OSB, and particleboard), plywood is considered by experts to be the best material for subfloors.
Plywood is moisture-resistant, suitable for all types of flooring installations, stronger, and stiffer. Plywood subfloors come in two different varieties: classic and tongue and groove. Installing tongue and groove plywood for subfloors is more common than the use of classic plywood. Tongue and groove plywood offers a stronger subfloor design that won’t sag or bounce at the seams between the joists.
Floor Joists
Floor joists are the wood or metal beams (i.e., set approximately 16 inches apart and parallel from wall to wall) that provide support to the subfloor layer in a floor system installation.
What Are Uneven Plywood Subfloors?
Fixing uneven plywood subfloors is one crucial step in the overall process of installing floors in your home. So, what causes plywood subfloors to become uneven?
Uneven plywood subfloors are subfloors that have not yet been leveled for installing the underlayment and flooring on top. As such, the subfloor at this stage in your installation has some dips, bumps, or a wavy surface appearance that needs to be fixed.
Homes that have issues with damage in the flooring system can also have uneven plywood subfloors that need to be fixed, but these exist for a completely different reason than uneven subfloors during the new flooring system installation. Very serious conditions of floor damage would need to be dealt with by a contractor and an insurance claim. This will handle a higher level of damage and restoration of your home’s flooring system and possibly even its foundation. Of course, this is all contingent on the type and the extent of the structural damage.
What Underlying Conditions Can Damage Subfloors?
Underlying causes and issues of damage to your subfloors may include carpenter ant or termite damage, delaminated subflooring, age-related settling, extra moisture, poor structural design, a rotten, cracked, or broken floor joist, soil movement, or foundation damage.
In the case that you have old floors that have been damaged by pests such as carpenter ants or termites, you will first need to remove these insects with a professional pest control service before doing any repairs to your flooring and subflooring.
Delaminated subflooring is a type of damage to subfloors known as “spongy” subfloor. This occurs when water or moisture damages the fibers of the wood, which begins to break them down so that they lose their structural integrity.
A floor joist can break or crack under stress and must be fixed by a contractor who knows local building code requirements for repairing floor joists. Soil movement and foundation damage is such a severe issue that it necessitates a building foundation specialist, someone who is well-skilled to fix homes that have much larger levels of structural damage.
Will My Homeowner’s Insurance Cover Uneven Floors?
Some of the causes of uneven plywood subfloors where there is damage are covered by homeowner’s insurance, but not all are. For example, most insurance companies will not cover damage that was due to a lack of proper care or maintenance by the homeowner or due to pests such as carpenter ants or termites.
Any long-standing unattended water damage issues or excess moisture may not be covered because it is considered a lack of prompt care and maintenance by the homeowner.
To file a homeowner’s insurance claim, be sure that the damage is significant enough to file a claim, or else you might risk a rate increase. Most homeowner’s insurance covers uneven flooring due to recent damage to the home, such as water damage. But you will want to check with your insurance to find out its terms and conditions to be sure.
Consider contacting your insurance company to see if they will reimburse you for getting an estimate from a local contractor or if they will do an appraisal themselves. An appraisal done by your insurance will reveal if there is damage and will help you to know how to proceed to repair your floors. They will explain to you in more detail what your insurance will or will not cover.
Your insurance will provide you with all the forms you will need to file a claim. If you plan to file a claim, you will want to do so as early as possible to get an appraisal and have your subfloors fixed quickly.
How To Fix Uneven Plywood Subfloors?
Before installing new floors, you must first level the subfloors. This will ensure your new floor is flat and level, too. Here’s how to fix uneven sections of your subflooring:
Tools needed:
- Steel ruler or measuring tape
- Spirit level
- Floor leveling compound (and primer if required by the leveling compound manufacturer and latex to mix it with if required by the leveling compound)
- Flat-edged plaster trowel or gauging trowel
- Sander
- Broom or shop vacuum
Instructions
- Check the uneven plywood subfloors for loose nails, screws, and staples that stick up above the surface and remove these.
- Drive screws through the subfloor into floor joists to replace any loose nails.
- Use a spirit level on the subfloor to assess the entire floor where uneven spots exist.
- Measure the dips using the ruler or tape measurer. You are looking for dips that are at least 1/8-inch or larger as these need to be filled.
- 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.
- Allow the leveler to dry as is instructed by the manufacturer’s product label.
- Remove hills or humps using a floor sander until the entire floor is level.
- Using a broom or shop vacuum, clean up the dust that is left on the surface of the subfloor before beginning to install the underlayment.
By following these steps, your plywood subfloor will be level, and all uneven sections will be fixed. This will make sure that your floors, when installed, will also be flat and level as they should be.
Please note that these instructions here are not universal for all types of flooring. To fix uneven plywood subfloors for other types of flooring installations, be sure to use instructions that are specific for that type of material. Tile, for instance, requires a backer board to be installed on top of the subfloor to create a stable, bondable substrate.
Fixing Uneven Plywood Subfloors Can Be Simple
Obviously, if plywood is not leveled before installing the underlayment and the flooring, the flooring can crack, break, and become uneven, which is a safety hazard. When fixing uneven plywood subfloors, be sure to follow the subflooring manufacturer’s instructions carefully and know and follow all local building codes.
Building codes exist to ensure healthy and safe building standards. If you do not take care to level plywood subfloors according to professional guidelines, you may run the risk that your floor system will not function as it should and may violate local building codes.
Fixing your own uneven plywood subfloors is easy to do if you have the know-how, and by taking this extra step to ensure all is level, you will ensure a successful flooring system installation.
Sources:
The Subfloor Is the Foundation of a Good Flooring Installation | The Spruce
How to Choose the Right Subfloor Leveling Techniques | The Spruce
How to Level a Floor | This Old House
