Technical Question: Basement Wall Insulation & Vapor Retardants (under 2006 IRC)

Panzer5

I'm working in Kentucky (Zone 4) which requires R10/13 insulation for basement walls under the 2006 International Residential Code (which KY adopted in late 2007). The question is whether I need to install the insulation as a remodeler - when I am not modifying the existing concrete - or whether I can rely on the existing walls...?

I'm working a bid to remodel a homeowner's unfinished basement in a home that's probably 5-7 years old. The basement is a dry, conditioned space, with unpainted concrete walls. I noticed that the joists for the floor above do not have insulation showing between the first floor and the basement space. If the basement walls were insulated at all, it would have to be on the dirt side of the concrete.

Because I plan to frame (2x4 & drywall) adjacent to the concrete walls - I need to know whether I have to install R13 batts & a vapor barrier (increasing my costs) - or whether I can simply frame & drywall.

Unfortunately, the code isn't exactly clear on this; and I'm having a hard time finding the answer on the net.

Anyone know the answer to this?

(This question could come up again given that fully half the houses in my area were built from the late 1930's through the early '60s. I presume those older houses have no insulation in the basement walls - but again, the IRC doesn't address whether the remodeler has to install insulation to meet code...)

genecarp

Can not speak for your exact location, but if you are finishing, and heating a basement, i would be wrong to not insulate, no customer in there right mind would want to shortcut that step. As far as the code, if you have filed for permits, and there will be inspections, you will be required to insulate based on your post. G

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Panzer5

That's my problem. The HO asked me not to insulate or install the vapor barrier - as a way of reducing my costs. I told him what the code requires - but we're in a debate as to whether that is actually required given the relatively new construction of his basement.

I suspect I am in competition with another builder who's willing to not install any insulation or vapor barrier - which mean's he's able to significantly undercut my price.

theman

5 You are changing the use of the basement from storage to living space.
the basement MUST meet the 2006 IRC code. check the insulation on the
out side of the foundation. you might be ok or just add a few inches on the inside, thats why no insulation was added to the ceiling. speaking of ceiling how what is the ceiling hgt. also youwill need to have a second means of egressout of the basement. and please get a bld. permit

al

SLSTech

Panzer - sorry but Gene & Al are correct

Codes are codes & even then they are minimum standards

Trust me when the HO has issues later, they or some representative of theirs (Insurance Company, etc...) will be coming after you for not building to code & your insurance will not cover it

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Panzer5

Wouldn't proceed without the permit. But I'm one of those anal types who likes to have everything laid out in my contract up front & my plan made before I get the permit.

Ceiling height is good (> 7ft), so I don't need a height variance.

- the egress requirement might be a deal killer for the HO... He's quibbling on a lot of things & asking me to rebid (i.e. how much to leave the walls drywalled & doors hung, but no paint, no trim, no tiling on BR floor, no carpet elsewhere, drop ceiling instead of drywall, etc. etc.) (makes me really consider charging for bids in the future!)

Frankly I'm thinking about walking away from the opportunity -- even though I could use the money. Bottom line though: while I'm willing to work with homeowners, as SLSTech writes: codes are codes. I just couldn't find the exact answer to this question in the book.

Ivinni

There is "basically" no R value to concrete (technically).

http://www.concreteconstruction.net/...8&refresh=true


Does the HO know what omitting the insulation will do to his heating bill? Let the HO know that the cost of the insulation, amortized over a 5 year period, will pay for itself and return money on his investment after that for probably the life of his addition. (generally)

That should help to make the sale.

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Tom M

Dont know your area and what R-value or AHJ requirement's you have but ridgid insulation will eliminate a pissing match with the building dept. I have seen in a local building dept a presciptive wall design that put's the vapor barrier on the inside (warm side for us)and a 1/2" min air gap on the back of the wall. I think the air space is a safe idea but think that prescriptive method is the wrong approach to basements. On another note we also have a provision in the UCC that exempts basements from insulation with a mechanical trade off. The trade off is a based on buildings with High Efficency equipment through out. I guess the logic is a more efficent unit omits less warm air loss in the mechanical room or house.
In NJ we also deleted the word"basements" in the IRC so only sleeping rooms need the egress escape.

Deadhead Derek

per code, IRC, AJ501.2 states that you may not make non conformities worse ( paraphrased) but as you are changing occupancy from basement to living space, no code related loophole at all, and the non conformities are moot. insulate away...

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neolitic

Check your code on the egress,
ours is amended to require the
egress windows only in sleeping rooms.

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(Sorry....it seems there really are dumb questions)

Kgmz

How can you not know the codes, laws, rules for your own state.

After a quick search here is your info from the,
As Adopted


3401.3 Compliance with other codes.

Burby

If this looks like something you will be doing a lot of or even just this one, pop into your local building dept and speak to one of the inspectors there to be clear. Sometimes it saves conflict in how one inspector to another as to what code defines. But seeing they will be the one to say yes or no, now would be a good time to speak with them, prior to any pricing and especially work performed.
I dunno if in your area every few years or so the tax accessor request a walk thru just to be sure of proper evaluation of homes, (more taxes they can charge) if they see a completed basement when before there was not one, your name may arise as to the one who made the change, a check with permitting office fails to show a permit was pulled, the what?
This possibility alone is worth always pulling the needed permits, not to mention if ever a fire, water damage resulting in an ins claim.
This is when H/Os sureley forget you reminded them about codes and proper procedure.

Besides always good to pop in your local building dept just to wish all there a very Merry Christmas
Wishing you & yours a very Merry Christmas.

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