When your finished floors start showing signs of damage, it’s often a byproduct of a worn subfloor. Subflooring issues can compromise the integrity of your home, leading to uneven floors, squeaking sounds, or even dangerous structural problems. Do you know who to hire to replace subfloors? We do.
This guide will help you diagnose common subfloor issues and learn who to call when you need subfloor replacements and repairs.
Recognizing the signs of subfloor damage before the issue grows into something more serious can save you time and money in the long run. Here are some common symptoms indicating your subfloor might need to be repaired or replaced:
Floor sagging, rot, and buckling can stem from the same root issue — often water intrusion or framing problems — and most subfloor problems have several causes (e.g., moisture and structural weaknesses). Therefore, you may need several professionals to fully address one issue.
A good starting point can be to hire a general contractor or structural professional who can diagnose the underlying cause of your subfloor problem and then bring in the right specialist to resolve it.
That said, there are many issues that can damage a subfloor, and not all of them require a GC. To help you pinpoint who to call, we’ll discuss the type of expertise you’ll need to find to handle some of the most common subfloor repairs:
General contractors and their framing crew can pinpoint weak joists, foundation shifts, or moisture damage. They’ll create a repair plan and oversee the project, coordinating with specialists as needed to ensure safe, efficient repairs.
If the sagging is significant, the contractor may loop in a foundation specialist to diagnose problem areas and reinforce the floor supports. That way, you can move forward with your projects on a solid, stable foundation.
A structural engineer can evaluate the integrity of your home’s foundation, diagnose the root cause of these issues, and develop a detailed plan for repairs. The severity may even warrant a full subfloor replacement.
Major structural problems include foundation cracks, shifting or settling foundations, bowing or leaning walls, sagging beams, and compromised load-bearing walls.
When you hire a structural engineer for your foundation, they’ll also ensure that all work complies with building codes and safety standards, which will help prevent future structural failures.
Note: In many jurisdictions, subfloor replacement — especially when framing or structural elements are involved — requires a permit or inspection to meet code. Check local regulations or consult your contractor about whether a permit or inspection is necessary.
For cosmetic and surface-related issues, flooring contractors are the go-to. Signs of a warping floor include uneven surfaces, raised edges, or gaps between floorboards. You might also notice cupping, where the edges of the planks rise higher than the center, or crowning, where the center bulges upward.
In these instances, hire a flooring contractor to inspect for moisture damage, structural issues, or installation flaws. Their expertise can help determine the next steps, such as spot repairs or total replacement.
Do flooring companies replace subfloors? Many flooring companies will address minor subfloor damage, especially when it affects the stability of the finished flooring.
If you notice small holes in your floors, hollow sounds when tapping, or a musty odor, you might be dealing with decay due to rot — usually brought on by pest infestations or excessive moisture. Carpenters can probe the wood for softness, identify hidden rot, and determine whether the problem is new or old.
If they suspect the damage is due to an inactive infestation, the carpenter will remove the compromised wood and replace it with a stronger wood to reinforce and level the subfloor. Flooring damage caused by active pest problems should be addressed first and will require an exterminator.
Rot induced by moisture — past or present — is repairable by the same carpenter, as long as you’ve addressed the cause of the decay. Larger soft spots that are also sagging will require significant repairs and are best left to a foundation specialist or engineer — not a carpenter.
Contact a local licensed plumber if you notice unexplained water stains or damp spots. Your floors could also be hiding a water leak if you have low water pressure or hear dripping sounds under the floor. These signs usually mean you have an undiagnosed water problem, which could have damaged your subfloor.
The plumber will use leak detection tools to identify the source of the leak and repair or replace the damaged area. During their inspection, plumbers can also check for secondary issues, such as mold growth or structural damage caused by prolonged exposure to moisture.
If past water damage has led to mold and discolored or warped flooring, it’s time to call a water damage restoration specialist (assuming you’ve already hired a plumber to address and resolve the water issue).
Water damage can appear as dark stains, buckling floorboards, peeling paint, or a persistent musty odor. Mold often resembles black, green, or white patches on surfaces and can cause allergic reactions.
Water restoration specialists assess the extent of the damage using moisture meters and thermal imaging to detect hidden moisture. They remove water-damaged materials, dry the affected areas with industrial dehumidifiers, and treat for mold to prevent regrowth.
The typical cost to replace a subfloor, including materials and labor, ranges from $900 to $5,000, or about $2 to $12 per square foot. Factors such as the size and location of the area and the type of subfloor material used can influence the overall cost.
Smaller projects with spot damage will fall on the lower end of this range, and putting down plywood underlayment is less expensive than replacing floor joists. Plus, minor issues left unaddressed can escalate to major structural problems that require more than just repairing the wood or panel underlayment.
Fixing broken floor joists, for example, runs $100 to $900 per joist on average. Repairing a concrete slab foundation beneath the subfloor can exceed $10,000.
You might be tempted to tackle subflooring repairs yourself. We understand — these projects are expensive, but they are usually necessary to maintain the integrity of your foundation. That said, we don’t recommend taking on these jobs yourself unless you have significant experience in home renovation and repairs.
If you’re on a budget, you could safely resolve very minor damage without calling a professional. For example, patching a small section of plywood subfloor might be feasible for someone with carpentry skills, but major water damage or structural issues should always be left to experts.
Some home improvement contractors offer flooring financing, which can make the project more affordable.
Knowing how to find the right contractor is crucial for successful subfloor replacement. With these tips, you can confidently take control of the process and choose a reputable professional:
When it comes to subfloor issues, structural problems, or water damage, knowing who to hire to replace subfloors can ensure you pick the right professional for the job. You’ll savee yourself a lot of time and several headaches when you choose someone who can properly diagnose the issue and provide lasting solutions.
