Cold roof

[dfattack]

Does anyone have any experience with installing a cold roof? or using/installing anything like this?

https://www.hunterpanels.com/product-over/product-listing/cool-vent

 

[chunk06]

What are you using it for? To get longer life out of wood shingles? People are lucky to be getting 20-25 years on cedar shingles laying on a plywood roof deck anymore so I see options like this to try to mimic the old spaced roof boards

 

[dfattack]

My original insulation installation in the roof sections with cathedral ceilings were not installed correctly. It's OK, but not as good as it should have been. I'm getting heat loss which in turn is melting snow and causing ice dams. I had the roof deck replaced in 2018 and while they were replacing the plywood they "fixed" the insulation from above. Then replaced plywood, ice and water and new shingles. I'm not getting any leaks from ice dams anymore but I can see the heat loss occurring in certain sections of the roof. I have researched my options and it appears installing a cold roof would eliminate the heat loss and ice damming once and for all. Some companies install their own version from scratch and my roofer turned me on to these panels from Hunter Panels. I was wanting to know if anyone has any experience with this concept of roofing and/or these panels.

 

[favoritos]

It is an interesting concept. I'm also curious about the long term durability. The installation looks fairly straight forward although I'm not sure how the venting is managed?
I also have a big span of cathedral ceiling that shows melting on the upper sections. No leaking so far. I have done as much insulation and air flow management as possible without tearing off the roof.
I've been racking my brain about how I will do the project when I redo the roofing. I am a little fortunate since I can currently get some airflow through the span. The insulation installed by the builder is not adequate and installed improperly. They put in rough cut chunks of 2" closed cell foam board between the rafters. The foam has plenty of gaps in the sections that I can see.
I've thought about tearing off the sheeting when I do the roof. That would allow me to use spray foam against the sheet rock. I could still leave enough gap to have adequate airflow. It wouldn't be simple or cheap.

The cold roof idea looks like it would give me a little more flexibility on the installation. It is an option if it works well.

My regular attic space and roof is great. I have gap sealed the entire attic as well. My question is related to just using this on the cathedral section.

 

[buddah2]

We're dealing with that issue right now...wish this had been available 12 yrs ago when we had metal roof put on...now can't afford to change it all out...so deal with the dam dams <g>

 

[Ohio Cat]

I have been in the commercial roofing business for 20+ years. This product works well for what you are trying to accomplish. It will work exceptionally well if you install a base layer of polyisocyanrate insulation first. Then stagger the cool vent system so none of the board joints line up. Also, make sure you securely fasten the whole system in place. Seal around all the pipes and vents with spray foam making sure you don’t impede sub deck air movement. Then make sure your eave to ridge ventilation is properly sized and balanced. The eave details can be awkward at times with this type of substrate construction. Good luck with the project!

 

[buddah2]

Completely off topic but Ohio Cat...does central OH still have a sno-mo club? We belonged to it when we still lived in Dublin (Sawmill Rd) back in the late 90s...just curious...used to meet at member's house out toward Delaware as I recall...

 

[chunk06]

My original insulation installation in the roof sections with cathedral ceilings were not installed correctly. It's OK, but not as good as it should have been. I'm getting heat loss which in turn is melting snow and causing ice dams. I had the roof deck replaced in 2018 and while they were replacing the plywood they "fixed" the insulation from above. Then replaced plywood, ice and water and new shingles. I'm not getting any leaks from ice dams anymore but I can see the heat loss occurring in certain sections of the roof. I have researched my options and it appears installing a cold roof would eliminate the heat loss and ice damming once and for all. Some companies install their own version from scratch and my roofer turned me on to these panels from Hunter Panels. I was wanting to know if anyone has any experience with this concept of roofing and/or these panels.

Any recessed lights in the cathedral ceilings? They are famous for heat loss. They hardly ever get insulated properly

 

[dfattack]

Any recessed lights in the cathedral ceilings? They are famous for heat loss. They hardly ever get insulated properly

No I don't have any of those. I have log collar ties that have mini up lights to light up the ceiling and in the dark corners. I specifically didn't want can lights in the cathedral ceiling for that reason. Plus I didn't want to have to change the bulbs

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I have been in the commercial roofing business for 20+ years. This product works well for what you are trying to accomplish. It will work exceptionally well if you install a base layer of polyisocyanrate insulation first. Then stagger the cool vent system so none of the board joints line up. Also, make sure you securely fasten the whole system in place. Seal around all the pipes and vents with spray foam making sure you don’t impede sub deck air movement. Then make sure your eave to ridge ventilation is properly sized and balanced. The eave details can be awkward at times with this type of substrate construction. Good luck with the project!

Is the polyisocyanrate insulation you are referring to the same insulation board that is shown on the Hunter panels? Or are you suggesting an additional layer of this material underneath the hunter panel?

 

[Ohio Cat]

It would be an additional layer beneath the hunter panels. You would stagger all the Joints in the insulating layers to eliminate/lessen the thermal breaks in the entire insulation System.

- - - Updated - - -

Completely off topic but Ohio Cat...does central OH still have a sno-mo club? We belonged to it when we still lived in Dublin (Sawmill Rd) back in the late 90s...just curious...used to meet at member's house out toward Delaware as I recall...

I believe there is one in the Delaware County area yes. I haven’t had a chance to hook up with them yet though.

 

[dfattack]

It would be an additional layer beneath the hunter panels. You would stagger all the Joints in the insulating layers to eliminate/lessen the thermal breaks in the entire insulation System.

thank you for your help with this. I’m curious how thick the added panels should be as well as which thickness you recommended for the hunter panels themselves now that there would be two layers of insulation?

 

[buddah2]

...I believe there is one in the Delaware County area yes. I haven’t had a chance to hook up with them yet though.

Yep, that's the one...was curious if they were still in existence...

 

[Tim in Indiana]

Had the same issue as you. My solution was to strip the roof and sheathing exposing the back side of the ceiling. I then had 6" of closed cell spray foam put directly on the drywall. Then we laid the 12" fiberglass batts back in place on top of the sprayed foam.

Next thing was adding ventilation channels. We nailed 2x2's on the side of the scissor trusses 2" down from the top of the upper truss chord. We ripped 3/8" plywood into 22-1/2" wide strips and nailed it to the top of the 2x2's creating an air channel from the soffit to the peak.

Then 5/8" OSB, ice & water then shingles. Nothing melts on the roof now. It is as cold as the outside.

We did everything in a day with five guys. Started at 6:00 am and had the foam guys showing up at 9:00, they were done by 11:00.

 

[favoritos]

Tim in Indiana, Thanks for your input. That method is what I am considering. Sounds like you have a much larger truss depth than my situation. (I'll have to go look again, but I think I may have 2X10 trusses.) My goal is to get a good insulation barrier with the closed cell foam and maintain the cross flow venting on the backside of the sheathing. I'm not sure if I can do a hybrid approach to the insulation with the smaller truss depth.

That brings up another question about insulation. I see so many different "recommendations" for thickness when using closed cell spray foam. What thickness is the most effective, or should I consider the hybrid method? My own thinking is to use the thickest foam layer possible. Probably end up with a max of eight inches of foam if the trusses are 2X10. The other option is the hybrid method and supplement with fiberglass batt. The ventilation channel is a critical part of using that method IMO. Seems like batting, or any loose insulation, has potential to sliding and bunching. It wouldn't take much to stop the cross flow.

 

[Tim in Indiana]

I have 7/12 pitch scissor trusses with an 18" heel depth. The least amount of depth is at the heel where it rests on the wall. So the 6" of foam plus the insulation leaves the fiberglass a bit compressed there but it isn't compressed once you move up towards the peak a foot or two.

I have used spray foam combined with fiberglass on every building I own. I believe in the air sealing benefits and the thermal break it provides. The proper thermal brake will prevent condensation where the warm inside air meets the exterior cold. This usually happens at the back of the sheathing or just inside the wall in the fiberglass. Once you introduce moisture into the wall the efficiency of the fiberglass drops dramatically. Using the correct depth of closed cell foam prevents the hot/cold air from meeting each other directly.

If you choose to use the less expensive open cell foam you must use much more to prevent air movement.

My understanding is in a roof anything over 5"-6" is the point of diminishing returns. My applicator would not recommend adding fiberglass above the 6" he put on but I already had the 12" batts so it was either stick them back in the roof or throw it away. Throwing it away made no sense to me.

I built my home and took great care when insulating. Even with foam boxes over the can lights and being very careful fitting the fiberglass we had ice damns. The spray foam stopped it completely.

Get a couple quotes from applicators in your area. They will know the correct foam depth for your zone.