LP SmartSide Swelling at the Bottom Edge — Board Repair
Some LP boards on the house are puffed up at the bottom edge or flaking where they meet the roof or deck. The rest of the siding is fine. Here is how those boards get fixed so they stay fixed.
When LP SmartSide is swelling at the bottom edge, JMB Builders replaces the swollen or delaminated boards, primes and seals every cut edge, and fixes the cause: siding too close to the roof, deck, patio or grade, a missing kickout, or a failed caulk joint. Across the Twin Cities and north metro, on existing houses, priced per project from photos within one business day.
- Priced per project, by the board
- Swollen boards replaced, cut edges sealed
- Clearance and kickouts fixed at the cause
- Painting quoted as its own line
- Licensed MN contractor BC809005
LP SmartSide holds up well when it is installed with its clearances and every cut edge is sealed. When it swells, it is almost always in the same places: the bottom course too close to grade or a patio, boards resting on a roof line with no gap, boards next to a deck ledger, cut ends at windows and corners that were never primed, and walls below a roof edge with no kickout flashing.
The repair is board by board. The swollen or delaminated boards come out, the wrap and sheathing behind are checked, and new boards go in with the cut edges primed and the butt joints handled the way the siding's install instructions call for. Then the cause gets fixed: a gap cut above the roof line with the step flashing checked, a kickout added, the bottom course raised off the patio, or the joints recaulked.
This page is for repairing an existing LP house. A whole new SmartSide install is on our LP SmartSide installation page. If the swelling is on a newer house, the builder, the installer or LP's warranty may be the first call; we can give you photos and a written list of what we see either way.
What you supply
- Photos of the swollen boards up close and of the wall they are on
- Whether the siding is factory-finished or painted, and the color name if you know it
- Leftover boards from the build if you have them
- The age of the siding and any warranty paperwork
What JMB supplies
- Removal of swollen or delaminated boards
- House wrap and sheathing checked behind them and repaired where wet
- New LP SmartSide boards in the matching profile, with every cut edge primed
- Clearance cut above roof lines, decks and patios, and step flashing checked
- Kickout flashing added where a roof edge ends against the wall
- Butt joints and trim joints detailed and sealed per the install instructions
- Painting as its own line when you want it, and photos in your job folder
How it is priced: per project
Quoted in writing from your photos within one business day. What moves the number:
- Number of boards to replace and how many walls they are on
- Sheathing or wrap damage behind the swollen boards
- Clearance fixes: cutting a gap at a roof line, raising the bottom course
- Kickout or step flashing to add at a roof-wall intersection
- Factory-finished touch-up versus painting the repaired wall
- One or two stories and access
Send a close photo of the worst board and a wider photo of the wall, including the roof line, deck or ground it sits over.
How long it takes
A handful of boards on one wall: half a day to a day, plus paint. Several walls or a kickout retrofit: one to two days.
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.
LP SmartSide Swelling at the Bottom Edge — Board Repair: questions, answered
Why is my LP SmartSide swelling at the bottom edge?
Water is getting into an unsealed edge. The usual causes are siding touching a roof line, deck, patio or grade without the clearance it needs, cut ends that were never primed, failed caulk at trim joints, and walls under a roof edge with no kickout flashing. The swollen board is the symptom; the edge detail is the cause.
Can you patch LP SmartSide siding or does the whole board get replaced?
Small woodpecker holes and dings can be filled, but a board that is swollen or delaminated at the edge gets replaced. The new board goes in the same profile with its cut edges primed, and the joints are sealed. Replacing the whole board, not part of it, avoids a new joint in the middle of the wall.
Can swollen LP siding be sanded down and painted?
It buys a little time at best. Once the fibers at the edge have swollen and opened up, sanding exposes more raw wood, and it swells again the next wet season. Replace the board and fix the reason it got wet.
Will new LP SmartSide boards match my existing siding?
The profile and texture match when the siding is still made in that line. Factory-finished colors fade, so a new board can look brighter for a while; painting the repaired wall corner to corner hides it. Painting is quoted as a separate line, or paint it yourself.
Is LP SmartSide swelling covered by warranty?
Sometimes. Warranties usually depend on the siding being installed to the maker's instructions, so installation errors like missing clearance may not be covered. Check your paperwork and contact the maker or the builder first on a newer house. We give you photos and a written description of what we find.
How much clearance should LP siding have above a roof or deck?
The install instructions set a minimum gap above roofs, decks, patios and the ground, and many swollen boards are ones set tight to those surfaces. When we replace them, the new boards are cut to leave that gap and the cut edge is primed. Step flashing and a kickout behind the gap carry the water out.
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 siding pages
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