Shingles/Roofing off gassing indefinitely?
User76447992
| Posted in General Questions on
Hi – As title states I’m wondering how long a new roof can actually off gas?
Nearly every Google search says a couple of weeks, but my roof was done a year ago in the summer and fast forward to this year and I still can smell the shingles outside the house in the yard and occasionally in the home (through skylights?) when temperatures go up to the mid 80s, which in the northeast is typically limited to the summer months.
Almost all google searches have been fruitless w a parroted response of a couple weeks.
Any idea here or is there maybe something else that I’m missing?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
My house was last re-roofed in 2004. On hot days, there is a chemical smell that we get at a few places in the house that I believe is coming from the roofing material - not sure if it's the shingles, the felt paper, or something else. A dark roof gets up to around 150F or more in direct sunlight in the summer.
We're doing some work on the roof and attic spaces this summer and will be completely re-doing the air barrier which I expect will put an end to the smells inside the house.
Thanks for sharing. I want to hope it will go away but looks like in your case 20 years was still a pain.
What do you mean by replacing the air barrier - air sealing from home to attic?
I think my smell may be the ice and water shield around the skylights? Did you have skylights or vaults in the area of the smell?
Yes, we have skylights and vaulted ceilings where the smells are, but we're about 50% vaulted and have several skylights so that's not saying too much.
Typically yes for reinforcing the air barrier that would be the ceiling below the attic. In our case due to a complex roofline with multiple vaults and attic spaces, plus for insulation reasons, we're converting to an unvented roof assembly with interior & exterior insulation. The existing roof sheathing will become the primary air barrier.
Thanks for the detailed reply. Had I known more about building science before getting the roof redone a year+ ago I think I may have switched to an unvented roof as well. I have a hip roof + gable roof bump out + two half vaults on both sides of the attic space. The intake + ridge vent isn't working whatsoever and I think it's possible the smells are exacerbated because the roof is just absolutely baking the shingles on hot days.
I'd have to rip down the ceilings in both vaults among other work to get spray foam... But my budget may only afford me to air seal the attic floor for now.
Who's to say our smells are the same source but in your case I'm assuming it didn't cause any health issues over 20 years. May just need to live with mine.
In my case there are visible gaps between the inside trim and the skylight curb when looking down from outside that I assume are contributing in addition to unsealed can lights, bath fan, etc.
If you have curb mounted skylights it is possible to remove them temporarily without disturbing the roofing, and fix that air sealing detail if you've tackled the more low hanging fruit.
Mine are deck mounted - but similar to you it seems there was a gap between the skylight frame and the drywall. I understand that velux has an interior trim kit that fits over the wood trim and can go over any interior drywall. I wish I knew that before kind of having someone ham fisted caulk the gap.
The chemicals that keep shingles flexible are the same ones that have an odor as they slowly off-gas. Shingles that are old, worn out and being torn off still have a slight odor. But it's usually not a problem, and shouldn't be making its way to the interior.
I wonder if the problem is really ice and water shield--another roofing system material with a strong odor, that remains permanently flexible--working its way to the interior due to the lack of a continuous air control layer.
Part of me thinks it's just the shingles because standing outside the home on a hot day if there is a breeze, it will pick up the odor from the roof - and it's the same asphalt type smell as indoors.
However, inside the smell is only noticable in the areas with vaulted ceilings - particularly in the drywall framing of the skylight shaft. The prior owner had baffling over insulation in the rafters of the vaults, so we cut in intake vents and ridge vents when reroofing but I think that the rafter bays with the skylights get intake as far as the bottom framing of the skylight and it stops there. The roofing company indicated that many rafters have notches or holes in the framing that allows air to start at the intake go around the skylight framing and out the ridge but even though I had requested a picture of this for confirmation they had already reroofed those areas.
I guess there could be other air leaks in the ceiling, can lights, ceiling fans, cracked drywall seams etc .. just not sure the best way to identify the problem area.
If you have any electrical fixtures in the sloped ceiling, they are almost certainly the source of the air leaks.
There are two can lights, a ceiling fan, and then the two skylights in this particular room. The other room is just a ceiling fan and the two skylights.
The can lights are definitely an issue. Last winter I noticed the only areas of the shingles that weren't covered in snow were above those lights.
Still odd that the smell is strongest in and around the skylights. Similar to the user above, there was a gap between Skylight frame and drywall on the interior, but we caulked that up. As you mentioned, maybe due to the lack of air going from soffit to ridge is just heating up that I&w shield and the smell comes out through the drywall into the living space. Not even sure if that is possible.