Subfloor repair
Subfloor repair is the work nobody plans for, because the subfloor is the one part of a floor you never see until something has gone wrong with it. A soft patch in front of a toilet, a spongy spot by a dishwasher, a bounce in a hallway: all of them are the structural layer under your finish floor telling you it has taken water or lost its fastening. It sits inside our floor repair and installation service.
Service family Floor repair and installation
Scheduling Monday through Friday, 8 a.m. to 4 p.m.
Service area Six counties across Southeast Michigan
Phone (734) 540-0347
What a subfloor is and what it does
Above the joists sits a structural sheet layer, usually plywood or oriented strand board, and on top of that whatever you walk on. The subfloor carries the load between joists, holds the fasteners for the finish floor and keeps the whole assembly stiff. When it fails, the finish floor above it starts moving, cracking or lifting even though the finish floor itself is fine.
The three places subfloors fail
Bathrooms, in front of the toilet and along the tub. Kitchens, under the dishwasher and beside the refrigerator. And entries, where thirty years of wet boots have gone through a worn finish. Almost every subfloor repair we do is in one of those three places, for the same reason: a small amount of water arriving repeatedly in the same square foot.
Bathrooms, and the toilet that has been leaking quietly
A toilet with a failed wax seal releases a small amount of water at every flush, straight into the subfloor around the flange. Nothing shows on the surface for years, and then the floor feels soft when you stand in front of it. By that point the sheet is delaminated and sometimes the joist below has suffered too. That repair begins with toilet repair before any carpentry.
What gets checked before we open a floor
- The finish floor type and whether it can be lifted and reused
- Moisture readings taken rather than a hand pressed on the floor
- Joist direction and spacing, from below where possible
- Any plumbing, wiring or ducting in the bay underneath
- Whether the damage stops at the sheet or reaches the framing
Plywood, board and the floors in older houses
Houses built here before the fifties often have diagonal solid board sheathing rather than plywood, which is strong but gappy and moves individually. Postwar houses use plywood. Since the eighties it is mostly oriented strand board, which is fine dry and turns to mush wet, swelling at the edges and never recovering. Knowing which one you have changes both the diagnosis and the repair.
Squeaks, soft spots and the difference
A squeak is a fastening problem and usually cheap. A soft spot is a material problem and always means opening the floor. Press with your heel in a slow circle: a floor that flexes and returns is loose, and a floor that gives and stays given has failed. The first is squeaky floor repair and the second is this page.
Cutting out and letting in a new section
The repair is surgical rather than sweeping. The failed area gets cut back to the centre of the nearest joists on all four sides, blocking gets added between joists to carry the cut edges, and a new panel of matching thickness is glued and screwed in flush. Done correctly the new section is stiffer than the floor around it and it never moves again.
Joists, blocking and the framing underneath
Where the water reached the joist, the joist gets assessed rather than covered over. Surface checking is cosmetic. Soft wood along the top edge means the bearing surface has gone. Adding blocking or sistering a new member alongside the old one restores it, and that is carpentry we do. Anything touching a bearing wall, a beam or a post is engineering and it goes out to a structural engineer.
Water damage, and finding the source first
We do not close a floor until the water that opened it has been stopped. A supply line, a shower pan, a roof above, a foundation problem and condensation all present as a soft floor. Our minor plumbing repair crew finds the plumbing sources and our water damage prevention work deals with the ones coming from outside.
Dishwashers, refrigerators and the kitchen leak
The kitchen version is slower and larger. A dishwasher supply fitting weeping a few drops a day, or a refrigerator ice line seeping behind the unit, wets a broad area under cabinets where nobody looks. The tell is a swollen cabinet toe kick or a floor that feels different underfoot near the appliance. Both need the appliance out and the floor opened to find the extent.
Around a shower and under tile
Tile hides everything until it cracks. A tile floor with a cracked grout line in a consistent place, or a tile that sounds hollow when tapped, often sits on a subfloor that has moved. Taking tile up is destructive by nature, and it cannot be saved, so we agree the finish plan before starting. Regrouting a floor over a failed subfloor is money thrown away, which is why tile repair and regrout starts with the same check.
Floor covering that has to come up first
Sheet vinyl and laminate rarely survive removal. Tile never does. Engineered and solid wood can sometimes be lifted in the affected area and relaid, depending on how it was fastened and whether the boards are still made. We will tell you plainly what can be reused and what has to be replaced before we cut anything.
Getting the new section flush with the old
- Matching sheet thickness exactly, including any underlayment
- Blocking under every cut edge so nothing deflects
- Construction adhesive as well as screws, not nails
- Fasteners set below the surface, never proud
- A straightedge across the repair before the finish floor goes back
Basements, crawl spaces and moisture from below
A first floor subfloor over an unvented crawl space or a damp basement takes moisture from underneath, which shows as cupping in wood floors rather than a soft spot. That is a ventilation and vapour problem rather than a repair. Where the space below is being finished anyway, basement finishing deals with it properly as part of the build.
Trim, baseboard and putting the room back
Opening a floor usually means pulling baseboard and sometimes casing, and the wall above often needs attention afterwards. Baseboard installation, trim carpentry and drywall patch repair come off the same visit, which is how the room ends up looking untouched.
How long the work takes
A single bathroom subfloor section, toilet out and back, is one day plus the finish floor. A kitchen area under an appliance run is two. Where joists need sistering, add a day. Sellers with a home inspection repairs list and a closing date should book early, because pre listing home repairs of this kind cannot be rushed.
Book subfloor repair with our crew
Stand in front of every toilet in your house and rock your weight onto your heels. If anything gives, call us while it is still a square yard rather than a room. We cover Ypsilanti and the surrounding counties, and an annual home check is where these get caught early. View our Portfolio, then contact us now for a free quote.
