Video · Leaks & repairs
Repairing Parapet Wall Seams on a Flat Roof
Watch “How to Repair a Flat Roof - Parapet Wall Seams” on YouTube (opens in new tab)
- Mod bit
- Built-up
- Metal
- Spray foam
- Acrylic-coated
What this video shows
SureCoat, a roof-coating manufacturer, covers repairing the seams where a flat roof meets a parapet wall. That wall-to-roof transition is one of the most common leak sources on Florida flat roofs, especially where stucco meets membrane.
Key points
- Clean and dry the joint, and cut out loose or failed old sealant before adding anything.
- The usual coating-system repair beds reinforcing fabric in a base coat across the transition, then covers it with a topcoat.
- Carry the repair up the wall and out onto the roof, not just over the visible crack.
- Check the parapet cap and the stucco above it. Water that gets into the top of the wall shows up as a roof leak.
Products in this video
The products used or shown, or the closest match we could verify. Typical price ranges, not live prices.
Polyester reinforcing fabric · $15–$35
HenryHenry 296 Polyester Repair Fabric, 4 in. x 150 ft
- Chemistry
- Other
- Size
- 4 in. x 150 ft
- Mod bit
- Built-up
- Rolled
- Metal
- Spray foam
- Acrylic-coated
- Silicone-coated
Thin, stretchy polyester you bed into roof cement or coating to bridge cracks, seams and flashing joints. It's the difference between a patch that splits in a month and one that lasts.
Read the fine print: Fabric goes into a wet base layer and must be fully covered by a top layer. Exposed fabric wicks water and breaks down in the sun.
Best for: Reinforcing patches, seams and flashing transitions
Check price on Amazon for Henry 296 Polyester Repair Fabric, 4 in. x 150 ft (opens in new tab)Affiliate link — we may earn a commission at no extra cost to you. Coverage and specs are the manufacturer's stated figures. Disclosure
Acrylic elastomeric roof coating · $90–$160
Kool SealKool Seal Premium Elastomeric White Roof Coating (10-year)
- Chemistry
- Acrylic
- Size
- 4.75 gal (5-gal pail)
- Mod bit
- Built-up
- Rolled
- Metal
- Spray foam
- Acrylic-coated
A budget-friendly, water-based white coating for roofs that drain well. Cleanup is soap and water, and you can recoat it with acrylic again in a few years, which is why many homeowners start here.
Read the fine print: Acrylics need a dry, warm window to cure. Rain or heavy dew on a fresh coat can wash it off. Acrylic won't bond to silicone, and on asphalt surfaces brown staining can bleed through unless you prime.
Best for: A budget white recoat on a well-draining mod-bit, built-up or metal roof
Check price on Amazon for Kool Seal Premium Elastomeric White Roof Coating (10-year) (opens in new tab)Affiliate link — we may earn a commission at no extra cost to you. Coverage and specs are the manufacturer's stated figures. Disclosure
Tripolymer roofing sealant · $8–$16
GeocelGeocel 2300 Construction Tripolymer Sealant, 10.3 oz
- Chemistry
- Other
- Size
- 10.3 oz cartridge
- Metal
- Mod bit
- Built-up
- Rolled
A tough, flexible solvent-based sealant that roofers grab for metal flashing, gutters, counterflashing and penetrations. It stays elastic and sticks to most building materials.
Read the fine print: Solvent-based, so expect a strong smell. It's a joint sealant, not a membrane patch, and like most caulks it won't bond to a silicone coating.
Best for: Sealing metal flashing, termination bars and penetrations
Check price on Amazon for Geocel 2300 Construction Tripolymer Sealant, 10.3 oz (opens in new tab)Affiliate link — we may earn a commission at no extra cost to you. Coverage and specs are the manufacturer's stated figures. Disclosure
Clear roof repair sealant · $10–$18
SashcoSashco Through The Roof! Sealant, 10.5 oz, Clear
- Chemistry
- Other
- Size
- 10.5 oz cartridge
- Mod bit
- Built-up
- Rolled
- Metal
A clear, very stretchy patching sealant for quick fixes around vents, skylights and flashing where black cement would look bad.
Read the fine print: Clear means any dirt you seal under it stays visible, so clean first. It's for small spots, not a substitute for a real seam or flashing repair, and it won't bond to a silicone coating.
Best for: Small leaks around vents, skylights and flashing
Check price on Amazon for Sashco Through The Roof! Sealant, 10.5 oz, Clear (opens in new tab)Affiliate link — we may earn a commission at no extra cost to you. Coverage and specs are the manufacturer's stated figures. Disclosure
Putty knife / scraper · $7–$14
HydeHyde Stiff Putty Knife, 3 in. (01440)
- Mod bit
- Built-up
- Rolled
- TPO
- PVC
- EPDM
- Spray foam
- Metal
- Silicone-coated
- Acrylic-coated
A stiff stainless blade for scraping off failed caulk, lifting loose coating and feathering patch edges.
Read the fine print: Don't pry at sound membrane laps, or you'll open the seam you're trying to protect.
Best for: Scraping failed sealant and feathering patch edges
Check price on Amazon for Hyde Stiff Putty Knife, 3 in. (01440) (opens in new tab)Affiliate link — we may earn a commission at no extra cost to you. Coverage and specs are the manufacturer's stated figures. Disclosure
Read the full guide
Leaks & repairs How to repair flat roof flashing and seams Most flat-roof leaks start at the edges and joints, not in the middle of the sheet: wall and curb flashings, edge metal, pipe boots, pitch pans, drains and open seams. Small repairs follow one pattern: clean down to sound material, use a sealant and reinforcing fabric (or tape) that match the membrane, carry the repair a few inches past the damage, and re-secure any loose metal. Torch work, heat-welding, drain rings and edge-metal replacement belong to a licensed roofer.Video by SureCoat Systems, embedded from YouTube. The summary, key points and cautions on this page are our own; SureCoat Systems doesn't endorse TheFlatRoofPro.com or the products listed. Roofing work for hire generally requires a licensed roofing contractor.