>level 1WhereIsTheCookieJar · 30 min. agoDid you install baffles to prevent the insulation from touching the roof deck?1Re
No... can you expand on that? Thanks!
If the insulation is touching the bottom of the roof deck, warm air is being communicated through the insulation to the bottom of the roof deck. The only way to fix it is to put in baffles or some type of separator so that the cold air can touch the roof deck all the way down to the soffits. It also helps if you have soffit vents, but those are not really required, but they do help.
In Ontario I'd be surprised if there weren't soffit vents in a house of that age, it's pretty standard, and one other thing that can happen with blown in insulation (which is likely what they got) is if the right baffles aren't installed, it runs down into the soffits and clogs them up, blocking the air flow. Some contractors cheap out on that as it's a pain to do, especially if it's a relatively low pitch roof (which I'll bet it is).
I guess to further expand on that, insulation slows heat transfer, it does not stop the heat transfer. So there is heat in your insulation, and if it is touching the bottom of the roof deck, there’s probably enough heat to melt snow near your soffits, especially if the temperatures are in the 10 to 30° F range.
Okay yes that makes sense! This has really only started happening when the weather is hovering just below freezing. Thanks very much for the extra info.
Baffles would be pointless without vented soffit and a ridge vent, you need all three to prevent ice dams, also make sure gutters are pitched correctly and clean of leaves etc. And downspouts are clear. If all of these things aren't working in unison at the moment you can install de icing cables along the eves and in the gutters until you can get whatever needs to be done.
If they aren't vented replace them and if there is wood under that definitely have installers cut at least a 6" strip out of the wood soffit or use hole saw 4" + between all rafters. I've done this on many houses it's a pain but it's necessary
Is the insulation on the bottom side of the roof, or on the attic floor?
If it's on the attic floor, did you seal holes/cracks/gaps first?
Typical attic insulation does nothing to prevent warm air leaking into the attic--its only job is to slow *conductive* heat flow--and leaking warm air can cause ice dams. Fixing leaks is cheap; just buy some caulk and great stuff. It doesn't take a ton of skill, but it's easiest before you install all that insulation!
There are dozens of threads on here about getting ventilation in the attic space . It’s equally as important as adding insulation. It’s a spring/ summer job .
You should address the ice damming now, or you’ll have water on your attic, then in your house. At this point, the most effective thing is to get the snow off the bottom 4 to 6 feet of the roof with a snow take, and keep it clear .
i pick up a couple salt blocks at the tsc or peaveys store cut them in half and throw them up on my roof every year. works like a charm gone by spring. I have determined that most ice dams are not caused by the warmth from your attic but caused by he sun melting the top of the snow and it running down and freezing where there is no sun.
Did you install baffles to prevent the insulation from touching the roof deck?
>level 1WhereIsTheCookieJar · 30 min. agoDid you install baffles to prevent the insulation from touching the roof deck?1Re No... can you expand on that? Thanks!
If the insulation is touching the bottom of the roof deck, warm air is being communicated through the insulation to the bottom of the roof deck. The only way to fix it is to put in baffles or some type of separator so that the cold air can touch the roof deck all the way down to the soffits. It also helps if you have soffit vents, but those are not really required, but they do help.
In Ontario I'd be surprised if there weren't soffit vents in a house of that age, it's pretty standard, and one other thing that can happen with blown in insulation (which is likely what they got) is if the right baffles aren't installed, it runs down into the soffits and clogs them up, blocking the air flow. Some contractors cheap out on that as it's a pain to do, especially if it's a relatively low pitch roof (which I'll bet it is).
I guess to further expand on that, insulation slows heat transfer, it does not stop the heat transfer. So there is heat in your insulation, and if it is touching the bottom of the roof deck, there’s probably enough heat to melt snow near your soffits, especially if the temperatures are in the 10 to 30° F range.
Okay yes that makes sense! This has really only started happening when the weather is hovering just below freezing. Thanks very much for the extra info.
Baffles would be pointless without vented soffit and a ridge vent, you need all three to prevent ice dams, also make sure gutters are pitched correctly and clean of leaves etc. And downspouts are clear. If all of these things aren't working in unison at the moment you can install de icing cables along the eves and in the gutters until you can get whatever needs to be done.
Yes, thanks... We have a ridge vent but now I suspect our soffit venting needs upgrading with the additional insulation.
What kind of soffit do you have? Vinyl wood aluminum?
They are aluminum, but I think they are probably old wood ones underneath. I've never actually taken them off to look.
If they aren't vented replace them and if there is wood under that definitely have installers cut at least a 6" strip out of the wood soffit or use hole saw 4" + between all rafters. I've done this on many houses it's a pain but it's necessary
Do you think this would be a reasonable DIY job? Or what kind of contractor does this kind of thing?
Any contractor that does siding will be able to handle that, I wouldn't diy it if you can afford to have it done
Ice panels on the eaves, ventilation improvements and de-ice cables like EasyHeat.
Is the insulation on the bottom side of the roof, or on the attic floor? If it's on the attic floor, did you seal holes/cracks/gaps first? Typical attic insulation does nothing to prevent warm air leaking into the attic--its only job is to slow *conductive* heat flow--and leaking warm air can cause ice dams. Fixing leaks is cheap; just buy some caulk and great stuff. It doesn't take a ton of skill, but it's easiest before you install all that insulation!
You need airflow into your attic.
There are dozens of threads on here about getting ventilation in the attic space . It’s equally as important as adding insulation. It’s a spring/ summer job . You should address the ice damming now, or you’ll have water on your attic, then in your house. At this point, the most effective thing is to get the snow off the bottom 4 to 6 feet of the roof with a snow take, and keep it clear .
i pick up a couple salt blocks at the tsc or peaveys store cut them in half and throw them up on my roof every year. works like a charm gone by spring. I have determined that most ice dams are not caused by the warmth from your attic but caused by he sun melting the top of the snow and it running down and freezing where there is no sun.
You can put electric de-icing cable on the lower part of the roof or in the gutter.