"R-19 batts are very air permeable, and on lengthy unobstructed rafter bays you have got really a stack outcome. It won't have a massive volume of air leakage to supply some drying there. Also, In the event the batts are unfaced or kraft-faced, the drying towards the interior would be considerable.
Quite a few spray foam roofing contractors within our market place are touting their skill improve efficiency on aged scorching tar and graveled flat roofs by adding three to 4 inches of shut cell spray foam. Many of these previous properties are flat roofs joisted with dimensional lumber, with parapets and have stucco vents Slash into the rim joists.
Since I've spelled out the proper way to do it, I will even Permit you to realize that Many of us have completed Everything you propose.
Many thanks to the enter. I see a stop by which has a structural engineer and 35 square of polyiso in my in the vicinity of potential.
A. To reap the benefits of the insulating worth of the rigid foam around the attic, you definitely would like to seal up any attic vents, therefore you absolutely don't need to create a ridge vent.
A further problem is, need to I keep on the identical insulation assembly outdoors? The last graphic displays a large 10' overhang. Should I vent this exterior portion or seal the underside in the p.t. plywood deck Together with the shut-mobile insulation?
My feeling is that the dew place profile would end up in the XPS foam board, for this reason a VB ought to be placed on very first deck. In order of assembly:
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Many thanks for your instructed addition into the listing of resources for creating internet site-created vent baffles. I've edited the textual content of my site to incorporate your suggestion.
My knowledge as I look at this site is the fact I do not need to worry about generating an air channel earlier mentioned the sheathed part as a result of rigid foam.
If you need to pick out a fabric that is a bit far more vapor-permeable on your ventilation baffle, it is possible to -- for example, lots of people use slender plywood or fiberboard With this location -- but you really don't have to. The EPS will function
Thanks, Martin and Stephen. Fortunately we've been in the situation the place we can easily pause and reconsider, as The brand new felt has actually been positioned, However they have not commenced installing shingles nevertheless. I'll discuss the specific situation Along with the contractor once again. I may be able to get him to reconsider.
Alright, so I'm somewhat anxious examining this thread. I have a terrific place that's paneled along with the rafters, which are 4x8, And that i installed sloped cans and was gonna insulate and end ceilings. My Major reason of performing this is that the roof is instantly over the beams and it will get incredibly hot in the summertime, Wintertime not a great deal of of difficulty as I reside in San Diego and temps seldom dip below freezing.
I have created log houses from the Yukon Territory in northern Canada for thirty yrs. Most log properties have cathedral ceilings. Most of the roofs We've got designed are as follows (from The underside up): log purloins, nominal two" (2x6) t&g decking, 6mil poly, one one/2" extruded polystyrene foam, 2x10 rafters on 24" facilities, seven" fiberglass, 2x4 strapping, 7/sixteen OSB, underlayment (15 lb paper, 30lb felt, or now we browse around this web-site would even use ice and water defend). There can be about an inch of air space under the strapping for both of those vertical and horizontal air flow. All roofs are vented with strip vents within the eaves and vents in the soffit (2x6 t&g) at the height at equally finishes. I'd disagree that venting is just not wanted for those who quit the airflow on The nice and cozy aspect, for two factors. Very first it really is very hard to prevent all airflow, Specially with conventional conventional tactics (ie chimney and plumbing vent penetrations throughout the roof) We now have several procedures created over time to try this out seal the vb for the eaves and gables, but there are still nail penetrations with the vb. All round I feel we had very limited seals but 1 could hardly ever say airtight.