UBC modular - energy audit - insulation sagging

Hi people!

We have a UBC ( Universal Building Codes ) modular house ( UBC qualifies to be installed on a foundation and looks pretty much like a "stick-built" house ) on a foundation here in the Denver area.

We had an energy audit last spring and they discovered ( among several things ) that some insulation is sagging under the house, in the crawl space. The insulation under here is installed and has plastic sheet over it, and in one spot it seems to have fallen down from there. We had a nightmare builder who took 1 year to even begin work on our lot and left this house sitting on a closed sales lot for that time ( the sales company went out of business ), so we have some problems from that.




So I called an insulation company to see how much it might cost for them to fix it ( I'm 63 and not into do-it-yourself in crawl spaces at this point ) and they suggested instead, why not seal the whole crawl space, claiming that works much better. He says they'd seal the vents, bottom ( already has plastic ) and side walls so no moisture would come up or in, and no cold air would enter the crawl space anymore. It sounds fine.

Two concerns though - cost and radon?

For a 2300 sq ft house, what would something like that likely cost? And we have radon here in Colorado, would that endanger us?

 

Do you know if there is any water being held in the sagging cover? You haven't had any shower/sink/toilet leaks to cause that, have you? Not sure if installing perlins across the insulation would suffice, but it sure couldn't hurt to keep it intact and prevent sagging or falling out.
Here in the south, we don't seal up crawlspaces, we ventilate the heck out of them. You have a different situation, extreme cold and moisture. Practice in certain areas dictates a complete sealing of the crawlspace as you mentioned. It isn't too expensive, but not super cheap, either. they will need to tie their moisture barrier to what you have on the floor either with duct adhesive sealant or tape, and it would need to go all the way up to the rim plate. Radon needs to be evacuated with special equipment. Impossible for us to tell how much it would cost. Get at least 3 estimates and check each one out.

 

No, there's no plumbing there, it appears to be under the front living room. I can tell because the floor there gets wet and slippery over that area, and nowhere else. So probably a cold air leak into that floor area from the sagging.

 

I don't think the sagging is a problem. It's that rip you need to be concerned about.

 

I had a guy come over today for an estimate. I was hoping they could just fix it. Instead he launched into a whole sales spiel, complete with pictures, how we really shouldn't just get it fixed, that they do complete energy audit alleviation. They want to seal off the whole crawl space instead of patching that one area. They said fixing it is useless, it was done wrong.

So they want to seal the whole crawl space totally and make a insulation compartment out of it, then do the main floor sealing that the energy audit said needed doing. The problem? We're talking $2500, maybe $3000, which we don't have.

We're expecting a global economic collapse within 3-6 months, folks.

He says we can save 35% on heating/cooling energy by doing this, but we're just hoping we can still be making the payments by this fall or next year.

If things collapse?...

I KNOW, he's trying to make a living too, but we're barely paying the bills, in a declining living standard in this country now, with food and fuel inflation. We're hoping we aren't living in a cave in a few years, or like in North Korea.

Crap...

 

You said "among other things" in your energy audit. The sagging insulation would be the least of my worries unless it was filled with water. Patch the other hole with tyvek tape. what are some of the "other things" they mentioned in the audit. Surely there was more than sagging insulation. If not, then I doubt any salesperson will save you 35% on your heat/cool bill by sealing the crawlspace. The proof isn't there.

 

We have one area of floor in the front living room that's wet a lot of the time. I think that's where the sagging insulation is, and it's allowing cold air in the crawl space up under there, which condenses water on the top of the floor, making it slippery. Probably not great for the wood under the floor either. That was why we asked these guys for an estimate.

 

Then just wait the 3-6 months to get the best rate.

 

You are correct about the flooring above the tear condensing moisture there. Don’t seal the tear; remove all the plastic under the cavity insulation. Install housewrap (Tyvek) to serve as an air barrier keeping the outside air from your insulation/subflooring. Check with your local Building Department as they may require a vapor barrier (old term)---e.g.- vapor retarder. If so, the plywood subfloor usually fits the bill with a perm rating of 0.7- a vapor retarder already exists if they used exterior glue plywood. Energy Savers: Vapor Barriers or Vapor Diffusion Retarders
Notice the v.r. goes on the warm-in-winter side of the insulation on the map provided. That would be at the insulation/subflooring, NOT below the insulation.

As for the radon…… you have a State accepted installation allowing the v.b. plastic on the dirt and passive vents to remove it. You are not required to use an “active system” as said ½ way down this article (your County may be different, check locally); https://docs.google.com/viewer?a=v&q...1DllenCnU9I8Rw

Scroll down to “Insulating a ventilated crawl space”; Energy Savers: Crawl Space Insulation
Notice- no plastic under the insulation…… the set-up crew was supposedly “certified” according to the State guidelines. I’m surprised they used poly sheeting (OR; is it a product similar to “Membrain”?) as this is basic information. Is there a label on it/ MemBrain™ - Mold Prevention - Insulation - CertainTeed

If you lived down South, the vapor barrier would be placed outboard of the insulation- toward the ground as yours is now. But then, crawls/attics should not be vented in a hot climate, according to building science: Joe's Top Ten :: Joseph Lstiburek

A “closed crawl” radon system, pp.11, Fig. 13; http://www.buildingscience.com/docum...ance-and-codes

Gary

 

As a novice homeowner, this is confusing to me. This energy company that came over yesterday wanted to seal off the whole crawl space from the house and from the outside. They said the bottom is already covered with good plastic, they'd just need to do the sides, sealing the vents and side walls with plastic, to the bottom crawl space plastic, and that would be it. Unfortunately $2500.

One concern of mine was the "sealing the vents part". I mean the builder was driven crazy by the city in 2004, they required so many vents down there. Now this guy says that was bad practice, that the vents should all be sealed and the sides sealed to the bottom plastic, sealing the whole space to the outside. He said the old vent theory proved false. But what if city code still disagrees and they come along and shaft us for it? Big Brother.

I'd love to save on energy but $2500? And the risk that the city won't tolerate sealing those vents?

 

As Gary mentioned, get with the city first. Hopefully it won't be a deterrent, but if so, you may have to go with a "plan b".

 

We don't have much money, I think we're just gonna wait and see when this collapse happens.