Insulate Hip Roof By Crawlspace Detail
R 5 for climate zone 3 r 10 for climate zone 4 except marine zone 4 and r 15 for marine zone 4 and climate zones 5 6 7 and 8.
Insulate hip roof by crawlspace detail. Step 1 add a vapor barrier. You could opt for thick insulation with a radiant barrier and an r 11 value. One of the best ways to protect your mansard roof from the problems of ventilation is to use a vapor barrier on the inside. With bird cut rafters all i had was 3 5 at the outer edge of the exterior wall plate after the site built foam baffles 3 4 xps were installed.
As a result your crawl space will stay warm during the winter and cool in the summer. How you insulate a crawlspace depends on whether it s ventilated or unventilated. A vapor retarder e g 4 or 6 mil polyethylene film should be installed on the ground to reduce moisture migration into the crawl space. C no slab edge insulation is recommended.
B insulate crawl space walls only if the crawl space is dry all year the floor above is not insulated and all ventilation to the crawl space is blocked. What is the best way to insulate and more importantly ventilate an addition with a hip roof and a very low pitch. In an unvented crawl space you should insulate the perimeter walls. Most building codes require vents to aid in removing moisture from the crawlspace.
With the 9 of insulation on the outside wall up to that baffle we ve not seen any sweating near the shower in winter and the house is so much. The roof overall is 26 x8 and the max height where it meets up with the house is maybe 2 2 1 2 high. Jm comforttherm kraft faced and unfaced insulation are all possible products to use for this application. The rafters are 2x8 s.
However many building professionals now recognize that building an unventilated crawlspace or closing vents after the crawlspace dries out following construction is the best option in homes using proper moisture control and exterior drainage techniques. In our case it was 5 in because of the 4 1 hip roof. Install at least as much continuous insulation on the inside or outside as required by the 2012 irc. To insulate the roof you will need to use a combination of insulation to fully protect the roof.
Cover the walls with insulation from the sill plate to the plastic covered dirt floor. Originally we insulated with the pink fluffy stuff. The sill plate is the first piece of framing lumber and it runs on top of the crawl space wall. If your crawlspace has stone and mortar walls you must use closed cell spray polyurethane foam.
It will keep out all the outdoor air.