Here's what you wrote: "I am aware that there is no caulk/sealant involving the side of your beam plus the place the place the drywall butts against it, so there is a compact air hole there. My memory is fiberglass insulation was utilized. There is without a doubt no vent in the roof."
For sure, in some cases you might want to plan ahead to make sure that your rafters are sized adequately to permit for insulation and venting. To learn more on acceptable strategies to insulate small-slope roofs, see this post: Insulating Reduced-Slope Household Roofs.
I live in northern Vermont, and I don't have plenty of encounter with air con to answer your concern about condensation on inside ducts.
I have insulated the perimeters with R-19 fiberglass and now I am asking yourself: was that a blunder? It's got craft paper and I used to be planning on a plastic sheet too, should really I skip that?
Martin, many thanks. I just talked to your roofer and he turned down the concept of only putting the foam around the family members room cathedral ceiling. That Unusual "jog" in the roofline, obtaining it all of a sudden bump up four" or eight" where by the spouse and children home starts off, in the middle of the again side of your roof, would defeat the concept of a constant slope for rain to return down when it hits the upper Portion of that back again roof. And so the 4" or eight" peak addition demands to continue throughout the total 2nd click over here story roof line.
two. It sounds like you're applying metal beams to frame your hips. As I am certain you recognize, these steel beams are thermal bridges. All insulation has to be on the outside aspect in the metal.
I am not a lover of entire peel-and-stick roofs, for a range of factors. But your plan click here to read will most likely be great. Just make sure that your roof sheathing is dry over the working day you install spray polyurethane foam -- since the sheathing will not be drying a great deal in possibly route following It is encapsulated in between peel-and-stick membrane and spray foam.
The most effective solution is to handle the problem from previously mentioned, by incorporating a major level of rigid foam higher than your present roof sheathing. You could Construct up the levels your self, of you can buy SIPs or nailbase panels.
Thanks for the response Martin. Would you still be satisfied to make use of that unvented technique to get a renovation predicament where by there is non-breathable membrane (eg bitumous 'felt') over reliable board sheathing?
Martin, I am grateful for your time and efforts, and after examining lots of of your respective replies, I am able to see you're keen about setting up factors appropriate. Appropriate for individuals, as well as the planet. Thanks for what you do!! Ryan Nelson
My view would be that the steep aspect of the mansard roof is a roof. This can be especially true if the outside of the sloped assembly is completed with roofing.
My sense is that if we're concerned about air leakage compromising the insulation's efficiency, vent channels are problematic.
If you are deciding on to develop a vented roof assembly, don’t fail to remember to include soffit vents and ridge vents.
I used to be skeptical of Bill Hulstrunk's find out here declare that AccuVent baffles could endure becoming dense-packed in an enclosed cavity.