A concrete pool deck sinks because it sits on the loose backfill around the pool shell, which settles for years and washes out where splash water runs into open joints. We lift the low sections with polyurethane foam through 5/8-inch holes kept clear of the coping, skimmer and plumbing, pitch the deck away from the pool again, then seal the joints. Most decks take a few hours.
By Rob Diederich, owner · Updated
Holes
5/8 in, clear of the coping
Typical job
2–6 sections
Time on site
A few hours
Warranty
Written warranty
The low section rises flush with its neighbor and drains away from the pool again; the joints and the coping joint are sealed. Drag the slider.
Pool deck leveling at a glance
Why it sinks
The deck sits on the backfill placed around the pool shell, the loosest soil in the yard
Target
A gentle fall away from the pool edge, like the deck had when it was poured, so splash and rain run to the yard
Holes
5/8 inch, kept back from the coping, the skimmer, the lights and the plumbing runs
Lifting
Short shots, outer edge first, so the slab rotates up to the coping instead of pressing on the pool wall
Typical job
2–6 sections
Time on site
A few hours
Then seal
The joints between deck sections and the flexible joint along the coping
Pavers
Concrete pavers around a pool are re-set by hand, not foam lifted
Signs your pool deck needs lifting
✓A lip at a joint on the walking path around the pool.
✓Water running back into the pool, or standing on the deck after rain.
✓The deck pulling away from the coping, with the flexible joint stretched or torn.
✓A section that rocks or sounds hollow when you walk on it.
✓A step down where the deck meets the patio or the lawn.
✓A crack through a section with one side lower than the other.
Why pool decks sink
An inground pool is dug oversize, the shell goes in, and the gap around it is filled back in. The deck is poured on that fill, often within weeks. The fill keeps settling for years, and every summer thousands of gallons of splash-out, backwash and rain run into the deck joints and carry fine soil out from under the slabs.
Backfill around the pool
An inground pool is dug oversize and the gap around the shell is filled back in. The deck is poured on that fill, which keeps settling for years after the pool goes in.
Fix: Foam fills the voids in the fill and supports the deck without adding weight to it.
Splash-out and open joints
Every summer, splash-out, backwash and rain run into open deck joints and carry fine soil out from under the slabs.
Fix: We re-seal the joints, including the flexible one along the coping.
Freeze-thaw
Clay-heavy Green Bay soil holds water. Every winter it freezes, swells and thaws softer, loosening the base a little more each year.
Fix: Sealed joints keep water out of the base, which is what freezes.
Lifting next to a pool: what's different
The pool wall is the one thing we don't want to push on. Before we drill, we map where the skimmer, returns, lights and plumbing run (tell us if you know), keep every hole well back from the coping, and lift from the outer edge in short, small shots while watching the slab. The foam fills the void under the deck and raises it in small steps instead of building pressure in one spot. The deck ends up flush at the coping and falling away from the water.
1Map the pool first, then set the lineWe note where the skimmer, returns, lights and plumbing run, mark the holes well back from the coping, and set a line that falls gently away from the pool edge.
2Drill 5/8″ holesPenny-sized holes go through the slab a few feet apart, kept off the edges and corners where concrete is weakest.
3Inject from the outside edge inFoam fills the void under the low section first, then each short shot raises it. We start along the outer edge so the slab rotates up to the coping instead of pushing against the pool wall.
4Patch and seal, coping joint includedHoles are grouted flush and every joint is re-sealed, including the flexible joint along the coping. That's where splash water was getting into the backfill.
Illustrations, not to scale. Most residential jobs take a few hours, and you can walk on the slab when we pack up.
Why lift a pool deck instead of replacing it?
Replacing a pool deck means breaking out concrete right beside a finished pool, protecting the coping and the liner from debris, and keeping the pool closed while new concrete cures. Lifting takes a few hours, nothing is hauled away, and you're swimming the same day.
Fraction
of what tearing out and pouring new concrete costs
Same day
Walk on it when we pack up, not days later.
No demo
No jackhammers, no dumpster, no torn-up lawn or landscaping.
5/8″ holes
Penny-sized and patched flush. No new slab that won't match.
Stays up
Foam adds almost no weight and doesn't wash out like soil.
Warranty
Written, and spelled out in your quote before you approve it.
Replace
tear out + pour
Demo
Base
Pour
Keep off
Still curing: full strength in about 4 weeks
Lift
foam, one visit
Done in a few hours. Walk on it right away.
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
Day 9
Day 10
Replacement timing is typical; a contractor's schedule and the weather can stretch it. New-concrete cure times from Concrete Network.
What it costs
Pool decks are priced by the section and the drop, with a job minimum. Decks with many small sections cost less per section than one big slab. See the leveling cost guide.
Your price, without a sales visit
Send three photos and a tape-measure shot. You'll get a firm price by text within 24 hours.
After the lift: what you'll see, and how to keep it there
Level pool deck, sealed joints, and a few penny-sized gray patches where the foam went in. The patches are close to concrete color and fade into older slabs within a season. We text you before-and-after photos before we leave.
Keeping it level means keeping water out from under it. Three things do most of the work: keep the joints and cracks sealed, backfill soil against any slab edge the lift left exposed, and keep downspouts discharging away from the concrete. Sealing is its own line on your quote; the rest is in what to do after your concrete is lifted.
Questions
Common questions
Can you lift a pool deck without damaging the pool?
Yes, with care. We keep the holes back from the coping, skimmer, lights and plumbing, lift from the outside edge in small shots and watch the slab the whole time, so the foam fills the void under the deck instead of pushing on the pool wall. Tell us where your plumbing runs if you know; if you don't, we work from the equipment pad and skimmer locations.
Can you lift the concrete deck around an above-ground pool?
Yes, if it's a poured slab. We keep the holes away from the pool wall and its footing ring and lift the slab back to a gentle fall away from the pool. Pavers or a wood deck around the pool are a different job.
Should I lift my pool deck before or after the pool is closed for the season?
Either works. Fall is a good time: the pool is covered, the deck is clear, and the lift stops another winter of water running into the gap. We lift from the spring thaw until the ground freezes, so late fall is fine as long as the soil isn't frozen.
What about the joint between the deck and the coping?
That flexible expansion joint stretches or tears as the deck sinks. After the lift we re-seal it along with the other joints. Keeping it sealed keeps splash water out of the backfill, which is what let the deck drop in the first place.
Does the pool need to be drained before you lift the deck?
No. The pool stays full, open or covered, and a full pool is actually better: the water supports the shell and the liner, and nothing we do touches the water. The foam is closed-cell and doesn't absorb water, so the damp backfill around a pool doesn't affect it either.
What do I need to move off the pool deck before you lift it?
Furniture, planters, the grill and anything else sitting on the low sections. The pool fence, ladder, slide and equipment stay unless they sit right where a hole needs to go or block the hose from the truck, and we'll tell you from the photos. The pool itself stays open or covered, whichever it is.
Can you lift the pool coping or the pool steps?
It depends on what they're attached to. Coping that was poured as part of the deck rises with it. Coping stones set on the pool wall belong to the pool, not the deck, so they stay put and we lift the deck flush to them. Steps inside the pool are part of the shell and aren't lifted; concrete steps leading up to a raised deck are a slab and can be.
