Offgassing from Roof Coming into House
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We feel we have to re-roof the problem area of the house which has a cathedral ceiling. We have added all the ventilation possible. Are there any Rain/Ice shields that don’t out-gas?
Any help appreciated! Thank you.
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Replies
Ice and water shield is on the exterior. Any offgassing is going to go off into the atmosphere, not into your house, so you’re unlikely to have any issues. That said, I’m not aware of any testing on these materials.
Bill
Not necessarily true? Along water ways, and hi wind areas this happens “all the time”! That’s like saying formaldehyde never entered the living space from insulation in the past… that’s exactly what’s it’s doing… if can smell it it’s in the area of your person…
I certainly thought it should go into the atmosphere, but it is in our bedroom instead. We re-roofed the house two years ago with rain/ice shield covering the roof due to skylights. We live in the Northeast so ice dams are an issue. Whenever the roof gets hot we get the out-gassing of asphalt material into our bedroom. We have re-worked the venting through the cathedral ceiling in the room to no avail. At that time we learned there is a beam cutting through one side of the cathedral ceiling that prevents proper venting.
Hi! I am experiencing the same thing. Did/how did you resolve your issue?
It turned out there was an air leak through the skylights into the room. I'd look for an air leak from outside.
Thanks! I have some small cracks that I will seal. Hopefully that helps.
How did you identify the air leak? Having the same issue as you described.
The best way is the depressurize the house with a big fan and use smoke to locate the leaks and plug them.
https://www.greenbuildingadvisor.com/article/blower-door-testing-a-living-building
https://www.greenbuildingadvisor.com/article/blower-door-qa-an-interview-with-collin-olson-from-the-energy-conservatory
https://www.greenbuildingadvisor.com/article/urban-rustic-blower-door-test
Walta
What’s happened as of this posting…? I’ve seen this before…I like to insulate all the way out to the gutter… never mentioned if your roof is a hot roof or not? I’m getting to this really late in your most likely finished projects?? Thanks
Next time… metal roofing…I know, cost $$$$?
If you have atmospheric gas appliances, attic fans may pull gas into the home…for ventilation; incoming more so then exit vents @ 1/150 nfa not 1/300 nfa (net free area)
So ventilation in soffits every joist bay, and continuous vents all the way around the home…hope this helps
1. So the idea is to insulate all the way to the gutter, that will stop any ice Dams! 2. Stop using asphalt shingles 3. All “Smart” water and or vapor-barriers that I recommend are non-toxic with out the smell!
Hi Linee,
Skylights need to be waterproofed and flashed well no matter what roofing underlayment you use. You can roof with felt and still have leak-free skylights. You probably want to use a peel-and-stick membrane around the rough openings, but you don't need to cover the entire roof with it.
If you are smelling the odor of your new roofing materials in the bedroom, then we can assume that you are experiencing a significant amount of air infiltration, which is a problem you should remedy, whether you re-roof with a less-smelly underlayment or not.
Would you please tell us a little more about this space? It is a bedroom under a cathedral ceiling with skylights, correct? Are there any other big holes in the ceiling, like recessed lights? Do you know anything about how to roof is framed and insulated? Tell us more about how you re-worked the venting?
Thanks,
Brian
No recessed lights in bedroom. Part of roofing goes over a screened porch which has recessed lighting. We have continuous eave vent which is on the outside of the porch. This we added. We took off our ceiling because the baffles were not properly aligned, and were failing. We re-installed these with new, better baffles. One side of the roof only had 3/4" clearance between the roof sheathing and the 18" beam at the peak of the roof. We have just cut that back. to about an 1 1/2". The real killer is a beam across the room about 2/3 rds of the way up the roof. This completely cuts off airflow. We drilled two hole in center of beam in each bay, but of course this is not enough airflow. Also the skylights prevent any airflow on 2 bays ea.
As far as the skylight and ice dams are concerned, it's not the skylights per say that are leaking. It's the heat from them (they are older) causing an ice dam that then backs water up under the shingles.
Ice dams are almost always a combination of conductive heat loss (poor insulation and/or thermal bridges) and convective heat loss (air leaks).
A blower door test will confirm cathedral ceiling air leakage and therefore where you have to seal to stop the odor from moving into your living space.
Peter
This house was built in the 1960's so I have no doubt there are air leaks everywhere. Can a blower test be done on an isolationable section of the house? The insulation has been replaced. New baffles installed at that time. Also new blue board and plaster. With the new coating I find it hard to believe this is getting in. My goal is to fix this issue so we can sell and build a Passive House. We have to move anyway, so we are planning to build next. Thank you for your input!
Linee
You can use positive building pressure in the summer to stop odor entry. What exact underlayment did you use?
Rain/ice shield from I think from Grace. How can I do a positive building pressure?
Linee
Any kind of fan blowing from outside to inside. Ideally with a pressure measurement to insure that you aren't doing any more than necessary to keep the odor out.
Following!
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