TPO Over an Existing Roof: When It Works — Step by Step
What to do about a TPO roof in the Lankershim corridor in the first forty-eight hours, and what to leave until Monday.
After a storm the useful work happens in the first two days, and most of it is documentation rather than repair. This is what to do about a TPO roof in the Lankershim corridor once the wind drops.
What actually matters
Punctures are the most common TPO failure by a wide margin, and most of them are made by people rather than weather. Rooftop trades drop tools, drag equipment and set ladders down on a membrane that is perfectly capable of resisting rain and not at all capable of resisting a dropped screwdriver.
What to do in the first forty-eight hours
Document before you touch anything: wide photographs to establish the property, then close photographs of each item of damage, all dated. Weld testing is the item to insist on. A probe run along every seam while the crew is still on site costs nothing and finds the cold welds that would otherwise be discovered by a tenant in December. A tarp fixed through sound covering creates damage that was not there before.
How the Lankershim corridor changes the answer
Along the Foothill corridor the buildings are largely commercial: big low-slope areas carrying rooftop plant, walked on regularly by trades who are not thinking about the membrane. Dust off the slopes settles on the surface and washes into the drainage with every storm. Older commercial stock with large low-slope areas, parapets, and equipment that needs servicing.
What we look at on an inspection
- Seam integrity, probed along the full length rather than spot-checked
- Punctures and abrasion, especially on traffic routes to rooftop plant
- Membrane shrinkage and any resulting tension at the perimeter
- Flashing and termination bar at every wall, curb and upstand
- Drain sumps and clamping rings, checked and clear
- Fastener plates showing through the membrane surface
- Weathering and chalking of the surface, particularly on exposed elevations
Common questions
Should I get a tarp on it straight away?
Only once it is photographed, and only if it can be fixed without putting new holes through sound covering. A badly fixed tarp creates damage that was not there before.
How soon do I need to report it?
Check your policy, because most impose a reporting window. Reporting early costs nothing and protects the claim.
The honest summary
TPO is a good system installed properly and an expensive mistake installed quickly. Seams and punctures decide its life, so protect the surface and test the welds. In the Lankershim corridor the thing to watch is membrane condition around the rooftop plant, parapet terminations, and every drain and scupper on the roof.
Free inspection, drone photography where access is difficult, and a written estimate with deck repair priced per sheet. No obligation.
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- Cool Roof Savings on Sherman Oaks Warehouse — Inspection NotesTPO Roofing