2016年7月9日 · Zone 5B, main level + full basement. First floor I built with 2x6 walls, and used mineral wool insulation with a smart membrane. Not that that should effect this question, but just giving a bit of info about the construction. Scenario : I have 12” thick i-joists, spaced 16” O.C., and want to insulate the rim-board void for two reasons: Noise reduction, and R …

2021年1月6日 · When I realized that the spray foam pushed the rigid foam piece away from the rim board after I had already done about 50 of the 80 rim joist areas, for the remaining 30, I have glued the first piece to the rim board with PL 300, and then glued the second piece to the first piece before applying the spray foam.

2020年1月10日 · For the east and west ends of the house where the floor joists are parallel with the wall, the top of the sill plate is completely covered by the 1 1/2" thick rim board, a manufactured wood I joist with 2 1/2" flanges adjacent to the rim board, and the bottom edges of 2 - 2" pieces of XPS rigid foam.

2017年12月16日 · In most cases, people installing rigid foam against a rim joist install it tight to the rim joist, without an air space. There are several reasons for this, but the most important one concerns air leakage. If there is any air leakage in that air space, the insulation performance is greatly degraded by the air space.

2014年11月22日 · I am insulating my rim joists with 2″ rigid foam board. Most of the rim joist is bare, and the foam fits along it nicely. Some sill boxes have some small irregularities (vent pipes, plumbing, etc) that I have worked around easily enough. However, there are many electrical cables running along the rim joist near the circuit breaker box.

2021年9月6日 · In this article, Insulating Rim Joists, Martin Holladay suggests installing 2 in. of rigid foam followed by a layer of fiberglass insulation as a money-saving approach. He warns: “Fiberglass batts should never be installed near a rim joist unless the rim joist is first insulated with at least 2 in. of rigid foam or spray foam.”

2021年1月25日 · Rigid foam is not "derived from spray foam". Polyiso is the closest chemically to spray foam, but it's made differently and in a controlled manufacturing enviornment, not in the field the way spray foam is applied to buildings (and it's usually the "in the field" part where problems come from in terms of the mix being off -- factories can control EVERYTHING about their manufacturing processes ...

2014年12月1日 · Why not a cobble cut and batt approach? 1.5"-2" of foam board (seems any of the types would work) followed by a piece of 3.5" or 5.25" roxul (likely eliminates the need for any fasteners) for a ~R-22 to R-35 assembly? Foam board against the rim joist (canned foamed in) provides the air and vapor barrier, roxul increases the R to a better number.

2025年1月14日 · The Rim Board will also get (2) layers of 2″ Polyiso rigid foam. The I-Joists are 11-7/8″ high. Following advice from other GBA posts, I will fasten the foam at the rim board with a little bit of adhesive, and 4-1/2″ screws through 60mm Polypropylene washers.

2019年5月21日 · When it comes time to finish out the basement installing a studwall as close as possible to the foam and use blown fiber insulation to raise the performance. It would be fine up to an additional ~R30 of fiber insulation before wintertime moisture accumulation at the foam/fiber boundary at the above grade section becomes an issue.