I can’t even start drawing plans for a single bedroom addition w/o CODE problems. Existing house has 2×8 joists. Can’t get R30 from 2×8 joists. IRC would allow it with a R19 footnote exception. Problem is WA Energy Code supercedes this (I think).
Do I just submit the plan with 2×8’s and see what they say? Ideas anyone? Thanks.
Look high and low to find and plug air leaks that cost you money and comfort.
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Replies
well
Ceiling joists? Attic? Shute the ends and blow thicker.
Sorry - Floor Joists. Ceilings easy as you said just "baffle & blow" to R50. I would hope the guy would be reasonable and allow a tiny addition using 2x8 Floor Joists but only he can say and so far hasn't answered my question.
Ok, that's what I thought first, but reconsidered.
Build your foundation shorter and sit the joists on top where you want the top of the new to be even with the top of the old framing.
or
I did this while wanting to make the exterior "stone veneer"-sort of-river stone veneer to match the original of the 1850 house we built onto.
I had the mason's lay up larger block-12" to where I wanted to start my framing-then they laid a course of 6" to provide me with a ledge on the inside-and a ledge for the riverstone outside. We still had to lay concrete brick or something on the inside to bring it up to proper ht for the joist framing. I also had to use in addition to the treated plate on top of the brick, a treated band as it was in contact with the back of the block.
so to maybe simplify-ledge inside to sit on, ledge outside for the veneer.
Have done similar to Calvin's suggestion. You might also use
deeper joists and notch them at the foundation, if 2x8 is sufficiently deep for load. You'd have to beef up the insulation at the rim joist with foam.
If the only issue is to make the top of the joists match, there are multiple ways to do that. I suspect you'd already have figured that out, though.
Floor joists over crawlspace, I take it?
Fill the bays with unface FG ro blow cells. On the underside, attache rigid foam board, with the gaps sealed and taped. Joists insulated to R25, add R6 for every inch of foam.
In theory, if you used 5.5"
In theory, if you used 5.5" of rigid polyurethane you'd just squeek through.
Insulate the crawl space walls and treat it like a short basement. No need for floor insulation.
Have you tried using both rigid foam and batt insulation? place the rigid up against the floor and batt below. 3" rigid provides upto r18, getting you most of the way there.
Just a thought
good luck
More than one way to skin a cat
One that this thread shows is that there are multiple ways to solve most problems, which is why I read this forum. It's a good way find alternative ways to look at the problem and the potential solutions.
All of the suggestions are good, the OP just needs to figure out the one that is "best" for his particular circumstances.
foam or combination foam and cellulose or FG
foam or combination foam and cellulose or FG