Based on segment R806.3 of your 2006 Global Residential Code (IRC), “No less than a 1-inch Room shall be delivered concerning the insulation along with the roof sheathing and at the location in the vent.†This type of vent Place might be established by putting in one inch by one inch “sticks†while in the higher corners of every rafter bay, accompanied by rigid cardboard, skinny plywood, OSB, fiberboard sheathing, or panels of rigid foam insulation.
I have already been working with rigid breadboard design expanded polystyrene inside the rim joists and assumed exactly the same might be place under the sheathing amongst the rafter bays, and with any gaps sealed by using a urethane spray foam such as Fill and Seal. Is there a high quality that makes spray foam satisfactory and rigid foam unacceptable?
Since I have described the best way to get it done, I will likely Allow you to realize that Many of us have performed That which you propose.
Yes, it can be Protected (although before you decide to question a question about a specific roof assembly, It might be superior to grasp your local weather zone).
Dependable info sets gathered by federal government or reliable study establishments. Some calculators count on person-produced knowledge, but this process isn't trustworthy Unless of course there is a lot of contributors who don't forget just the amount of they expended on almost everything from healthcare to bread in the last calendar year.
You must check with an electrician about The easiest method to provide your ceiling electrical packing containers. There are various possible options -- some visible from the inside, and many hidden by The brand new foam.
Doug I agree, a lot of wrongs "overthinking" and overdoing. I as soon as needed to resupply a health care provider constructing an plane with dozens of AN plane bolts mainly because they were tightened to The purpose of breaking the bolts. Significantly less is much more sometimes... Along with the KISS rule.
On an unrelated topic: The Cold Local climate Housing Exploration Heart has generated a video clip (below) demonstrating a person approach to setting up an insulated cathedral ceiling. The method proven inside the video clip is particularly appropriate for builders in climates topic to ice dams.
The R value of your Lower'n'cobbled foam + exterior foam needs to be a minimum of forty% of the center-cavity R benefit for more dew issue Command for the foam/fiber boundary in zone 5. If It can be developing a tad shy of that right before introducing the exterior foam it's actually not a major offer during the short-term, but if it'll be five-a decade just before re-roofing to boost the foam-R to previously mentioned 40% of the overall It is well worth making use of vapor barrier latex primer over the gypsum board, or a sensible vapor retarder among the gypsum board & fiberglass.
Hence the issue is: seal the stucco vents and include the spray foam roof and don't worry about condensation? There's little or no low-hanging fruit in our kind of building, especially on existing houses, And that's why folks are remaining sucked in the spray foam roof rip-off.
Have area above garage Centre with closets on either side between the closet kneewalls and the eaves. Insulation above the room part is 6 inches of froth slabs sealed by "Wonderful Things" spray-in foam. Previously mentioned this ceiling foam and underneath the roof plywood, there are one inch x 20. inch unobstructed foam encased ducts involving the rafters for venting on the roof peak vent. The side sections exterior the knee walls are insulated with rolled fiberglass fiber with durovent ducts in between the insulation plus the roof plywood. You'll find significant soffit vents at The bottom from the durovent ducts.
On account of their unscientific origins, code specifications for venting roofs tend to be misunderstood. It’s really worth setting up a few basic specifics:
Sure a cathedral ceiling element might be quite equivalent nevertheless the problem of numerous cathedral ceilings could be the extra structural factors, electrical containers, and the desire for wood board ceilings all which begin compromising the drywall layer which within your element is made use of on the air barrier.
Regardless of whether you choose to really make it vented or unvented, get the small print appropriate — for the reason that each and every cathedral ceiling presents options to create big problems