Anyone have any questions about roofs?
Does it harm the rafters or sheathing to put spray foam insulation directly under (on) the roof sheathing (between the rafters)?
Aside from the lack of ventilation issue, how would you notice a leak before it’s too late (rot)?
I have been thinking about the ramifications for using this stuff since they came out with it also, and I’ll second the motion for asking about a leak…?
What if you need to get at the roofing structure?
I can only imagine what a mess that would make for repairs.:roll:
Applying insulation directly to the underside of the sheathing voids the shingle warranty for ventilation reasons, and if the roof leaks, it might not be evident until advanced decay had significantly weakened the roof sheathing.
Here’s an excerpt from IKO’s warranty which states they will warranty their shingles on a non ventilated/insulated roof for ten years.
Just for discussion purposes, do you think if the shingle are OK after ten years they would go the whole 25 or 30?
REDUCED WARRANTY COVERAGE FOR INSTALLATION OF SHINGLES ON INSULATED ROOF DECKS
The coverage under this Limited Warranty is reduced for any Shingles, which are applied to any of the following:
a) roof deck assemblies (of slopes greater than 2 in 12) where foam insulation is prefabricated into the roof deck system
(commonly known as “nail board insulation”), or
b) where insulation is installed immediately beneath an acceptable roof deck system.
In the event that such Shingles are installed on insulated or unventilated decks the Warranty Period available to the Owner is
reduced to 10 (ten) years with no Iron Clad Protection coverage. The annual reduction figure in this case shall be 10% per year.
What is the difference in repairing a insulated roof structure as compared to a water or waste drain repair beneath a slab. I have seen the mess it makes not pretty
BTW IMHO it has not been field tested long enough to know the ramifications just like PEX when will they both raise their ugly heads
What I said about this issue is generally true and since we don’t research, worth stating, but what is “iron clad protection coverage” and what does it mean? Roofing companies seem to like using language that consumers can’t figure out and can only understand by hiring an attorney. Is any consumer going to know what an “annual reduction figure” is?
Most companies that produce asphalt shingles require ventilation on the underside of the sheathing. We’re not required to be able to identify the 2% (or whatever) who don’t, so I guess it’s a matter of how the narrative is worded. So point taken Peter, it should say “most shingle manufacturers…”
What I said about this issue is generally true and since we don’t research, worth stating, but what is “iron clad” and what does it mean?
I guess my point was that this type of roof system is becoming more common and I think the shingle manufactures will have to update their warranties to stay competitive.
Also, don’t you think shingles on a “hot” roof that make it to that ten year mark and are still in good shape will make it to the 25-30 mark? I guess we don’t really have enough history to know for sure, at least in my area.
Will this or any of the other roofing pdf’s (InterNACHI Roof Field Guide Total Package) make it to a print version? You call them “Field Guides” but many don’t use digital readers in the field. Also, pdf’s don’t add to the weight of the bookshelves in my office!
Spray foamed rafters/truss cavities must have air chutes/baffels between the rafters forming an air space for the attic and sheathing to breath. Of course ridge vents are also needed.
Hey Ron… how many terra-cotta roofs do you see in Hutchinson?
Shingles that make it to the 10-year mark in decent shape have a better chance of reaching their warranty length but who knows, Peter?
Manufacturing shingles to withstand higher long-term heat would mean producing higher quality shingles, so they would charge for that. I’m sure they’ve all thought about it, but it’s not that common a roof structure.
It’s a tough business. People don’t know anything about shingles and they often buy by price, meaning that’s what those producing good shingles have to compete with. Each time the bar gets lowered other manufacturers have to decide what to do.
You can have them bound at Kinko’s for not too much, Jeff.
Have you seen the study that was conducted in… Lav Vegas I think…
They measured the roof temperature of two identical houses, one vented and one not, and there was only a six degree difference. I thought it was interesting. It may have been done by the Building Science Corp.
I don’t think I have, Pete. It’s been a couple of years since I was putting a lot of time into research, but I remember seeing contradictory information about shingle color.
Like with with politics in the Middle East and Global Warming, some things, the more you learn, the less you realize you really know, there’s real credible opinions on both sides of a question, and it all just gets more confusing.
A study by Building Science Corp. is pretty credible, but I’d want to know more, like the type and amount of venting provided in the vented house, was there any wind blowing, etc.