Self Leveling Floor Before LVP — Floor Flattened So the Planks Lock
The new vinyl plank is in the garage, and the floor under the old carpet has a dip by the patio door and a hump at the subfloor seam — flattened first so the locking joints hold.
Self leveling a floor before LVP is about flat, not level. JMB Builders checks the subfloor with a long straightedge, fills dips with patch or a poured self-leveling compound, planes or sands down humps and seams, and fixes loose subfloor before the vinyl plank goes down. Spot-fill or full pour is decided from the check. Priced per room, quoted from photos within one business day, Twin Cities metro.
- Priced per room
- Spot-fill, plane or full self-level pour
- Checked against the plank maker's flatness spec
- Quote from photos in 1 business day
- Licensed MN contractor BC809005
LVP is thin and rigid, and its click joints only hold on a flat floor. Over a dip, a plank bends each time it is stepped on until the joint lets go and a gap opens or an edge peaks. Most plank makers print a flatness spec in the install sheet, commonly around 3/16 inch over 10 feet, and a floor outside it can void the plank warranty. Read the sheet in your box; we work to it.
Flat is not the same as level. A floor can slope across the room and still be flat enough for LVP. What matters are the dips and humps under a straightedge. In 1970s ramblers and split levels we often find humps at the subfloor seams, a crowned joist, a dip in front of the kitchen sink, or old sheet vinyl patched over a soft spot.
The fix is chosen from what the straightedge shows. Small dips get a trowel-applied patch. Humps and ridges at seams get sanded or planed down. A floor that is low across a wide area gets primed and a self-leveling compound poured, with dams at the doorways, and on a wood subfloor a reinforcing lath first when the maker calls for it. Loose or soft subfloor is fixed before any of it.
What you supply
- Photos of the room and the floor with the old covering off, if it is off
- The LVP brand and product name, so we read its install sheet
- Whether the floor is wood subfloor or concrete
- The new flooring, or have us quote supplying it
What JMB supplies
- Straightedge and laser check of the whole room, low and high spots marked
- Loose subfloor screwed down, squeaks and soft spots fixed first
- Humps and seam ridges sanded or planed down
- Patch compound for dips, or primer and self-leveling pour with dams
- Lath over wood subfloor when the leveler maker calls for it
- Drying time respected before the planks go down
- Photos of the prepped floor in your job folder
- LVP installation after, quoted on the same job
How it is priced: per room
Quoted in writing from your photos within one business day. What moves the number:
- How far the floor is out: a few spots vs. the whole room
- Spot patching vs. a full self-leveling pour
- Wood subfloor, which may need lath, vs. concrete
- Loose or soft subfloor that has to be fixed first
- Old flooring or glue that has to come up
- Whether the LVP install is on the same job
Tell us the LVP product so we quote to its install spec, and send photos of any spot that bounces or sounds hollow.
How long it takes
Spot-fill in one room: a few hours, flooring the next day. A full pour: one day to prime and pour, then the drying time the maker lists before the planks go down.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized quote within one business day. We only come out to measure first when the job needs a tape measure — no pressure, no games.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Spot-fill and plane
A few dips filled with trowel patch and a few ridges sanded down. The most common prep on wood subfloors in ramblers and split levels.
Full self-leveling pour
A room that is low across a wide area, primed and poured with self-leveling compound behind dams at the doors. Flat enough for LVP once it cures.
Subfloor repair first
Soft, water-damaged or loose subfloor replaced or screwed down before any leveling. There is no point patching over a floor that moves.
Self Leveling Floor Before LVP — Floor Flattened So the Planks Lock: questions, answered
Do I need self leveling compound before LVP?
Only if the floor is out of the plank maker's flatness spec over an area too wide to spot-fill. Many floors need only a few dips patched and a few seams sanded. A full self-leveling pour is for a floor that is low across much of the room. We check with a straightedge and tell you which.
How flat does a floor need to be for vinyl plank?
Most LVP makers call for something close to 3/16 inch over 10 feet, and some are tighter. The number is in the install sheet in the box and is the one that matters for the warranty. It is about flat, not level: a floor can slope and still pass.
Can you use self leveling compound over a plywood subfloor?
Yes, with the right prep. The subfloor has to be solid and screwed down, primed with the leveler maker's primer, and many products call for a metal lath stapled down first on wood. Gaps are sealed so the pour does not run into the basement.
What happens if LVP is installed on an uneven floor?
The planks flex over the dips, and the click joints wear until they separate or peak. You hear hollow spots and see gaps open. It can also void the plank warranty. Prepping the floor first is cheaper than relaying it.
How long does self leveler take to dry before installing LVP?
It depends on the product and how thick the pour is. Many can be walked on in a few hours, but the maker lists a longer time before flooring goes down, and we follow that sheet. Spot patches are usually ready the next day.
Can a floor be sanded down instead of leveled?
The high spots can. Humps at subfloor seams and ridges from old patches are sanded or planed down. Dips still need to be filled. Most floors get a mix of both: take the highs down, fill the lows.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and for the builders and dealers we sub for. Counts come straight from our job log; no customer names.
Get a written quote for this job
Three photos and a sentence is enough. You hear back within one business day. Or text the photos to 763-204-2099.
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Read morePage reviewed September 26, 2026 · JMB Builders LLC, MN license BC809005 · All flooring pages
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