At a glance: Completed 2026-09-28: rear slope shingle & plywood repair on Burgundy Lane, Ballwin, MO 63011. Office: St. Louis, 314-429-6000.
A soft spot on the back of the roof
The problem on Burgundy Lane was on the rear slope, out of sight from the street. When a section of roof decking gets wet and stays wet, the plywood softens, delaminates and starts to sag between the rafters. Shingles nailed into that wood lose their grip, and the area keeps getting worse with every storm.
The fix is not just new shingles on top. The bad wood has to come out. That is why this work order called for removing up to three squares of shingles so the crew could see and reach the full damaged area.
What a square means on a repair
Roofers measure in squares. One square is 100 square feet of roof. Up to three squares here meant opening as much as 300 square feet of the rear slope. That gives room to cut the damaged plywood out at the rafters, set a full new sheet, and weave new shingles back into the surrounding courses so the patch does not have a hard seam.
Opening a bit more than the obvious damage is normal. It lets the crew find the edges of the wet wood instead of guessing.
Replacing the plywood
About one sheet of plywood was replaced. A full sheet is four by eight feet. The crew cut out the bad section along the rafter lines, set the new sheet with the right gap for expansion, and nailed it off to the framing. New decking gives the shingles solid wood to hold on to again.
If more wood had turned up soft once the shingles were off, the homeowner would have been shown photos before anything extra was done. On this job, one sheet covered it.
Shingles back on the rear slope
With the deck solid, new shingles went back in the open area and were tied into the existing roof. Starting at the bottom and working up, each course overlaps the one below, and the top courses slide under the existing shingles so water keeps flowing over the repair instead of into it.
The crew then cleaned up the yard and hauled away the old shingles, nails and wood.
Why rear slopes get overlooked
Most homeowners in Ballwin look at the front of the roof from the driveway and never see the back. Rear slopes often face the weather, sit under trees, or drain onto lower roofs, and damage there can go unnoticed for a long time. A ceiling stain in a back bedroom or a sagging line on the back roof is usually the first sign.
If you have not seen the back of your roof in a few years, a free inspection will show you.
Roofer near me in Ballwin, 63011
Ballwin is one of the busiest areas for our St. Louis crews, and we have done replacements and repairs on several streets nearby. If you search roofer near me in 63011, 63021 or 63088, our St. Louis office at 314-429-6000 can usually get someone out quickly to look at a soft spot or leak.
We document the deck damage with photos and give you a clear repair price before any work starts.
Repair now, replace later
A section repair like this keeps the roof working and protects the house until the homeowner is ready for a full replacement, if one is ever needed. If the rest of the roof is in good shape, a targeted repair can buy many more years. We will tell you honestly which situation you are in.
How water gets into roof decking
Decking usually gets wet from one of a few places: a lifted or missing shingle, a cracked pipe boot, a gap at a wall or chimney, or condensation from a poorly vented attic. Plywood can handle getting wet once and drying out. What ruins it is repeated soaking over months, where the layers separate and the nails stop holding. On the back of a roof that nobody looks at, that slow cycle can go on for a long time.
Part of every deck repair is finding the cause, not just replacing the wood. If the source is not fixed, the new sheet will fail the same way.
What to check from inside your attic
Take a flashlight into the attic on a dry day and look at the underside of the roof deck. Dark stains, white mineral rings, moldy patches or nail tips with rust on them all show where moisture has been. Press gently on a stained area with a screwdriver. If it sinks in, the wood is soft. Take a photo and send it to us; it helps us know what to look for before we climb up.
Ventilation and the life of a repair
Many Ballwin homes from the 1970s and 1980s have limited soffit intake, which traps warm, wet air in the attic. That moisture condenses on the underside of the deck in winter. When we repair decking, we also look at the vents and tell the homeowner if ventilation is part of the problem. A balanced attic keeps the new plywood, and the rest of the deck, dry for years.
Backed by our workmanship warranty
The repair on Burgundy Lane is covered by our lifetime workmanship warranty. If the area we worked on leaks because of how we installed it, we come back and make it right. Keep the invoice with your house papers; it helps if you ever sell.
Fall is a good time to fix it
Late September is a smart window for a deck repair in west St. Louis County. Temperatures are mild enough for new shingles to seal, and the work is done before freeze and thaw cycles start pushing water deeper into soft wood. Waiting until a January ice storm usually means a bigger opening and more plywood.
What the crew did, step by step
- Removed up to three squares of shingles on the rear roof slope.
- Cut out and replaced about one sheet of damaged plywood in the same area.
- Installed new shingles where they were removed and tied them into the existing roof.
- Cleaned up and hauled away the related debris.
Questions homeowners in Ballwin ask about this repair
How do I know if my roof decking is bad?
Signs include a sagging or wavy area, a spongy feel underfoot, and leaks or stains below. A roofer can confirm by checking the deck from the attic or with shingles removed.
Can you replace just one sheet of plywood?
Yes. Damaged decking can be cut out at the rafters and replaced with a new sheet.
How much is a square of roofing?
A square is 100 square feet of roof area.
Will the new shingles match?
We match the existing shingle as closely as possible. New shingles usually blend in after a season of weather.
Do you do roof repair in Ballwin?
Yes. Call our St. Louis office at 314-429-6000.
How long does this kind of repair take?
A section repair like this is usually finished in one day.