If you own a mill house in East Durham, Edgemont, or Old West Durham, your floors probably aren’t level. Most people who call us about it already know that. They’ve watched a toy car roll to one side of the kitchen, or they’ve noticed the bedroom door swings shut on its own. What they want to know is whether it’s a problem, and whether new floors can go down anyway.
Usually they can. A new floor doesn’t need the house to be level. It needs the surface under it to be flat. Those are two different things, and the difference decides what the job costs. Sometimes, though, the slope is the house telling you that something underneath has moved or rotted, and that has to be dealt with before anyone puts down a single board.
Why Durham’s Mill Houses Lean
These neighborhoods were built for mill workers. East Durham grew up around the Durham Cotton Manufacturing Company mill, which started running in 1885. Edgemont came in the early 1900s, when Julian Carr built houses for workers at the Durham Hosiery Mill. Most people also call the Golden Belt village next to it Edgemont, even though the city’s name for it is Morning Glory. Old West Durham was the Erwin Cotton Mills village, block after block of small one-story houses with front porches. Erwin started selling its houses to workers in the 1940s and Golden Belt did the same in the 1950s, so every one of these houses has had decades of different owners and different repairs.
Most of the mill houses we’ve been under sit on brick piers over a dirt crawlspace instead of a continuous foundation. In a lot of them the original pine floor is the only layer, nailed straight to the joists with no subfloor underneath. Durham’s red clay shrinks in a dry summer and swells back up when it’s wet, and after a hundred years of that, some piers have sunk, some have leaned, and some of the wood sitting on them has rotted. The floor follows whatever the framing does.
What We Usually Find Under A Sloped Mill House Floor
Sunken or leaning piers are the most common cause. A pier that has dropped half an inch takes the girder and every joist resting on it down too, so you get a dip that runs across the room. When the slope is worst in the middle of the house and better at the outside walls, that’s the first place we look.
Rotted sills are close behind. The sill is the beam that sits on the piers around the outside edge of the house. Where dirt, mulch, or a bad downspout has kept it wet for decades, it goes soft and crushes, and the floor along that wall drops with it. Termites like the same conditions. If that’s what we find, the steps in our post on rotted subfloors and termite damage apply here too, even though we wrote that one about Cary.
Then there’s the framing itself. Some of the original joists and girders are light for the distance they span, at least by today’s standards, and over the years plumbers and HVAC installers cut notches through joists to run pipes and ducts. We went into notched joists in detail in our post on what we find under 1940s Durham bungalows, and mill houses have the same problem.
The back rooms are their own story. Plenty of mill houses had an open back porch that somebody later closed in to make a kitchen or a bathroom. Porch floors were built to slope away from the house so rain would run off, and when the porch got walls, the slope stayed. If your kitchen or bathroom tilts toward the backyard while the rest of the house feels fine, that’s very likely what you’re standing on.
Two smaller causes round it out. Some Old West Durham houses were built around a center chimney, and a chimney sits on its own heavy footing. When the framing around it settles and the chimney doesn’t, you get a hump in the middle of the floor. And almost every house has a patch or two from an old kitchen or bath remodel that sits higher or lower than the original floor around it.
Level And Flat Are Not The Same Thing
Level means the floor matches the horizon. Flat means it has no humps or dips along its length. A floor can tilt an inch from one wall to the other and still be flat, the way a tabletop is still flat when the table has one short leg. New flooring cares about flat. You care about level, because level is what you feel when you walk across the room.
For hardwood, we work to the National Wood Flooring Association’s numbers. With nail-down hardwood and fasteners 1-1/2 inches or longer, the subfloor should be flat within 1/4 inch over 10 feet, or 3/16 inch over 6 feet. Glue-down floors and shorter fasteners need it tighter: 3/16 inch over 10 feet, or 1/8 inch over 6 feet. If the flooring manufacturer’s spec is stricter, theirs wins, and you have to meet it to keep the warranty.
Floating floors like luxury vinyl plank and laminate handle a dip worst of all. The planks bridge over the low spot, flex every time someone steps there, and the locking joints start to click and can eventually fail. Each manufacturer prints its own flatness requirement in the install guide, and we read it before we quote.
We also don’t try to make a mill house that’s more than a hundred years old dead level, and we’ll talk you out of it if you ask. The walls and door frames have spent a long time settling into the shape the house is in now. Jack the floor back to perfect and the walls crack, and doors that closed fine start to bind. What we aim for is a floor that’s flat enough for the new flooring and close enough to level that you stop noticing it.
How We Check A Sloped Floor Before We Quote It
I do every estimate myself, and on a mill house it takes a little longer than usual. We shoot a laser line across each room and mark the high and low spots on the floor in pencil, so you can see the shape of the problem instead of guessing at it. A long straightedge on the worst areas tells us whether we’re looking at a gentle tilt or a real dip. Then somebody goes into the crawlspace to look at the piers, sills, girders, and joists under the low spots, and we take moisture readings on the framing and the floor. If the old floor is coming up anyway, we lift a board where it won’t show and look at what’s underneath.
By the end of that visit, the slope usually falls into one of these groups:
- The house settled a long time ago and has stopped moving, and the tilt is gentle. We flatten the surface and leave the framing alone.
- One or two joists are sagging or notched. Those get sistered with new lumber, and then the floor gets flattened.
- Piers, sills, or a girder have failed. That’s structural work, and it comes before anything else.
Who Fixes The Framing, And Why It Needs A Permit
North Carolina lets you skip a building permit for a lot of work on a single-family house, up to $40,000. That exemption doesn’t cover the addition, repair, or replacement of load-bearing structures, which is spelled out in N.C. General Statute 160D-1110(c). Piers, sills, girders, and joists are all load-bearing. So a structural fix under a mill house needs a permit no matter how small the bill is.
Pier and girder work belongs to a foundation or structural repair contractor, sometimes with an engineer involved. We install floors. We don’t lift houses. What we do is show you exactly where the problem is and come back for the floor once the framing is solid. If the combined project reaches $40,000, North Carolina also requires a licensed general contractor, and our post on what to ask a licensed and insured contractor covers how to check.
A good structural contractor raises a settled house slowly, a little at a time, so the walls have time to adjust. That can mean a wait between their work and ours. We’d rather wait than put a new floor on framing that’s still being moved.
How We Flatten The Floor Itself
Once the framing is sound, the rest is ours. The method depends on how far off the floor is and what’s going on top of it.
High spots get taken down. That can mean planing the top of a joist that sits above its neighbors, or sanding a ridge out of the subfloor. Low spots get built up. Where a joist sits low, we fasten a tapered strip of wood to the top of it, cut to match the dip, so the new subfloor lands flat. Where several joists have sagged together, sistering a new joist alongside each one, set to a string line, does the same job and stiffens the floor too.
When the original pine floor is the only layer and it’s coming out, we put down a real subfloor of plywood, glued and screwed to the flattened joists. If the old pine is staying and getting covered, a plywood layer over it does the same thing. Either way the new floor goes onto something flat and stiff instead of old boards that have cupped and worked loose.
For small dips under tile, vinyl plank, or laminate, we use a patch or leveling compound made for wood subfloors and feather it out to nothing at the edges. Tile needs the most care, because a floor that isn’t flat shows up as tile edges sitting higher than their neighbors. Our post on tile lippage in older Durham homes explains what happens when big tiles go down over an uneven floor.
Nail-down hardwood is the most forgiving choice for an old house that’s been flattened but still isn’t perfect. It’s fastened every few inches, so it stiffens the floor, and if it’s finished on site, the sanding takes out small height differences from one board to the next. That’s part of why we usually recommend site-finished hardwood in Durham’s older houses.
If your original pine or oak is staying and you only want it refinished, sanding can make it look close to new, but it can’t take the slope out. Any leveling has to happen from underneath before we sand. Our page on hardwood floor installation and refinishing has more on how we handle old floors.
Where A Leveled Room Meets The Rest Of The House
Flattening one room changes its height compared with the next one, and that’s where a rushed job shows. We’ll go over these with you before we start:
- Doorways, where the new floor may end up higher than the old one beside it. A transition piece or a gradual ramp in the subfloor keeps it from turning into a trip edge. Our guide to transitions and thresholds shows the options.
- Interior doors, which sometimes need trimming at the bottom to clear the new floor.
- Baseboards, which were cut to follow the old slope. Once the floor underneath is flattened, gaps can open up under them, so they may need to be scribed or reset.
- The dishwasher. If the kitchen floor goes up, measure the opening under the counter first. Otherwise you can end up with a dishwasher that won’t slide out the next time it needs service.
What It Does To The Price And The Schedule
Flattening is part of floor prep, and it goes on your written quote line by line before we start, so it isn’t a surprise at the end. What moves the number is how much of the floor is out of tolerance, whether the old floor has to come up, and whether a new subfloor goes down. The bungalow post linked above lists rough prices for common subfloor fixes like sistering and plywood overlays, and we price the same work the same way in a mill house.
Structural work is priced by whoever does it, and it runs on their schedule. A wet crawlspace can also hold a job up. If there’s standing water or the framing reads wet, that gets fixed first, or the new floor will move with the seasons. Our post on hardwood acclimation in the Triangle explains how much the moisture in a house here swings over a year.
Getting Your Mill House Looked At
We’ve been a flooring contractor in Durham since 2009, working out of our shop on Obie Dr. East Durham, Edgemont, and Old West Durham are all inside the city, so they’re an easy trip for us. On a free in-home estimate I’ll map the slope, look under the house, and tell you which parts we can handle and which need someone else first. You get a written, fixed quote by email, usually within a day or two.
Vilchis Hardwood Floors
237 Obie Dr, Durham, NC 27713
(919) 794-1116
[email protected]
Monday through Friday, 9:00 AM to 5:00 PM
Serving Durham, Raleigh, Cary, Chapel Hill, Carrboro, Hillsborough, Apex, Morrisville, Garner, and Wake Forest.
Request a free in-home estimate
Frequently Asked Questions
Is A Sloping Floor In An Old House Dangerous?
Usually not on its own. Plenty of mill houses have had the same tilt for decades. What matters is whether the house is still moving. New cracks in the walls, doors that started sticking this year, a soft spot in the floor, or a floor that bounces all mean something underneath is still changing, and that’s worth a look before you make any flooring decision.
Can You Install New Hardwood On A Floor That Isn’t Level?
Yes, as long as the floor is flat within the flooring’s tolerance and the framing under it is sound. A gentle, even tilt can take nail-down hardwood. Humps and dips have to be fixed first.
How Can I Tell If My House Is Still Settling?
Draw a short pencil line at each end of a wall crack and write the date next to it. If the crack grows past the marks over a few months, the house is still moving. Doors are another clue. If one that used to close fine starts rubbing at the top corner, something has shifted since it was hung.
Do I Need A Permit To Level My Floors In Durham?
If the work touches piers, sills, girders, or joists, yes. North Carolina requires a permit for repairs to load-bearing structures no matter what they cost. Replacing the floor on top generally falls under the state’s exemption for smaller jobs. If you’re not sure where your project lands, call the Durham City-County Inspections Department before work starts.
Will Leveling The Floor Fix My Sticking Doors?
Sometimes, but don’t count on it. A door that’s been trimmed over the years to fit a sagging frame can start sticking in a new spot once the floor moves. Plan on some door adjustment as part of any job that involves leveling.
Mario Vilchis runs Vilchis Hardwood Floors out of 237 Obie Dr in Durham. He’s been installing and refinishing wood floors in the Triangle since 2009 and shows up to every estimate himself. Reach the shop at (919) 794-1116.
