HVAC lineset leaking through the roof
When HVAC linesets penetrate the roof rather than exterior walls, they often cause ceiling leaks that installers blame on unrelated roof issues like valleys. This leaves homeowners struggling to find a reliable fix without paying thousands more for contractor repairs.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Applying temporary sealants like NP1 or Duralink around the penetration
- 2Installing a zipper boot or pitch pan with pourable sealer
- 3Rerouting the lineset entirely through the interior, garage wall, or soffit
- 4Taking boarding off to inspect the water ingress
- 5Asking the original contractors to come back and address the leak
- 6Applying caulking or sealant over the holes and flashing
- 7Waiting for the rain to stop
- 8putting out buckets to catch water
- 9deciding whether to attempt a DIY roof repair or hire a professional roofer
- 10trying to take photos from the yard
- 11Getting roofers to propose replacing asphalt shingles and torch down roofs
- 12Checking permit records to determine the age of the roof
- 13investigating the source of the leak by opening up the ceiling
- 14inspecting the area with protective gear like gloves, a face shield, and a plastic sheet
- 15getting a ladder to inspect and photograph the eaves and shingles
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“It’s leaking, and I’m sick and tired of putting out that buckets.”source ↗
“Since the install it's started leaking. Never before, I'm absolutely sure.”source ↗
“Asked them to come back, and they're saying it's an issue with the valley, and it's £4k more to repair. Not in the scope of the original work.”source ↗
“We don't have £4k and now we have a roof which was leakier than at the start.”source ↗
“Having consistent leaks due to rain and roofers have proposed to replace both the asphalt shingles and torch down roofs.”source ↗
“Wanted to see if the pictures of the roof indicate a roof replacement is merited.”source ↗
“I can't get on the roof because I don't have a tall enough ladder and I don't trust myself on it.”source ↗
“I have a neighbor upstairs and over the course of several months I have noticed some bubbling on the ceiling.”source ↗
“Opened up the ceiling to find this. I captured this after the neighbor flushed the toilet. Can anyone help determine where the leak is coming from?”source ↗
“Since it’s leaking, I’d still have the vent pulled and checked rather than just caulked.”source ↗
“The places where he pierced the roof with AC electrical box and the place where he decided to insert a “vent” are leaking like crazy.”source ↗
“Once it cools down a bit I want to take the “vent tube” out, and see if I can properly secure the switch box to fix the leaks. It all being in the valley makes me question if I can do it myself.”source ↗
“Our roof ridge is leaking from possible splashback.”source ↗
“The roofers who replaced our roof is saying that because of our steep roof, we should have the roof ridge taken out in replace of roof vents.”source ↗
“Is there truth to that or did they botch the installation and don't want to fix the real problem?”source ↗
“Newish roof installed 3 yrs ago for an insurance claim, now having a leak in the ceiling.”source ↗
“i suspect it's due to roofers not wanting to pull out the old drip edge and putting a new one in over the top causing the metal to bend.”source ↗
“I am pretty pissed at this workmanship.”source ↗
“Within the last year we've noticed a ceiling drip in a spot in the house below a roof location with HVAC lineset running through.”source ↗
“Obviously I'd prefer the cheapest/simplest option that fixes the problem, but I'd also prefer to 'do it right' and not just bandaid things.”source ↗
“I’ve got water coming in around this bathroom fan vent.”source ↗
Where this came up
People with this problem also raised
- 6How to temporarily waterproof a damaged roof until replacement
- 22Water keeps getting in the house during heavy rain
- 14How to tell if roof flashing is installed wrong
- 2Why are my roof shingles lifting near the gutters?
- 55How to fix a leaking water pipe in a tight space
- 2How to fix a leaking skylight after rain