Hi folks
I'm getting insulation blown in my attic. I have a couple good quotes for open cell but I'm reading a lot about moisture and rotting. Is this the boogieman and a non issue if done properly? I have an air handler up there. Totally unconditioned at the moment. Do I need to do closed cell?
For roofs there are a lot of things to take into account and you have to consider it as a whole system.
"Open-cell spray foam is not the enemy. It has its strengths and weaknesses, just as any building material. You don't have to be worried about using it. You just need to know how to do it right.
Don't use open-cell spray foam in cold climates (IECC climate zones 5 and higher) without a vapor retarder.
Make sure the installers get the attic sealed airtight. Test with a blower door to commission it.
Monitor the attic's relative humidity and temperature. Low-cost thermo-hygrometers with remote sensors are widely available. You could also put an alarm on it, as Skye Dunning describes in the comments below.
Condition the air in the attic. Lstiburek says to do it for every spray-foam attic. Others, like David Butler (see his comment below) say you need to do it only if a moisture problem develops.
There you have it. Open-cell spray foam is a perfectly acceptable insulation product to use in attics. Do it right, and your roof will NOT rot."
Open cell rotting roofs? - ( New Window )
For roofs there are a lot of things to take into account and you have to consider it as a whole system.
"Open-cell spray foam is not the enemy. It has its strengths and weaknesses, just as any building material. You don't have to be worried about using it. You just need to know how to do it right.
Don't use open-cell spray foam in cold climates (IECC climate zones 5 and higher) without a vapor retarder.
Make sure the installers get the attic sealed airtight. Test with a blower door to commission it.
Monitor the attic's relative humidity and temperature. Low-cost thermo-hygrometers with remote sensors are widely available. You could also put an alarm on it, as Skye Dunning describes in the comments below.
Condition the air in the attic. Lstiburek says to do it for every spray-foam attic. Others, like David Butler (see his comment below) say you need to do it only if a moisture problem develops.
There you have it. Open-cell spray foam is a perfectly acceptable insulation product to use in attics. Do it right, and your roof will NOT rot." Open cell rotting roofs? - ( New Window )
Funny - I had already read that. It's just a lot of info to process!
do you still have my email?
Quote:
The issue would be warm moist air moving through the foam and condensing on the cold surface of the roof during winter. So, you need to install a vapor barrier between the foam and the attic space.
For roofs there are a lot of things to take into account and you have to consider it as a whole system.
"Open-cell spray foam is not the enemy. It has its strengths and weaknesses, just as any building material. You don't have to be worried about using it. You just need to know how to do it right.
Don't use open-cell spray foam in cold climates (IECC climate zones 5 and higher) without a vapor retarder.
Make sure the installers get the attic sealed airtight. Test with a blower door to commission it.
Monitor the attic's relative humidity and temperature. Low-cost thermo-hygrometers with remote sensors are widely available. You could also put an alarm on it, as Skye Dunning describes in the comments below.
Condition the air in the attic. Lstiburek says to do it for every spray-foam attic. Others, like David Butler (see his comment below) say you need to do it only if a moisture problem develops.
There you have it. Open-cell spray foam is a perfectly acceptable insulation product to use in attics. Do it right, and your roof will NOT rot." Open cell rotting roofs? - ( New Window )
Funny - I had already read that. It's just a lot of info to process!
Yes, unfortunately, the more complex the system, the greater the number of failure modes. The most important thing to consider is where moisture can go. Keeping it simple reduces risk. That is why vented attics are the standard as there is less chance for failure. Also, for every homeowner the code enforcement is your friend. You have hopefully hired an expert and hopefully the expert is doing the job you hired them to do. Code is there as a risk mitigation. Unfortunately, code is the floor to doing a good job, especially around weatherization and energy efficiency. Run from any contractor who doesn't pull permits
do you still have my email?
hey Dean - just emailed you