An impossible insulation job

[Stormin Mormon]

Friend of mine lives in a two story house. Built long enough ago, that the kitchen has a hole in the chimney for a wood stove. Probably turn of the last century. Aluminum siding exterior, lath and plaster for the inside walls. No signs of any insulation. Natural gas 70% efficiency furnace.

The attic has an access hatch from second floor. On the second floor ceiling is about half an inch of some kind of wood particles, and then maybe two inches of blown fiberglass. The roof is peaked in the center, all four sides slope down. Very shallow pitch roof -- much much room to work up there. There is no fiberglass or anything under the roof wood. Unsure about any tar paper under the shingles.

I've been trying to figure out how to insulate on the cheap. Don't want to drill the aluminum siding, that's not replacable. Could drill the lath and plaster to blow in cellulose, would be a major mess. Second floor really could use a vapor barrier, also the side walls could use vapor barrier. Some places where the plaster has fallen off, he's filled between the lath with Great Stuff expanding foam, to help keep out the cold draft.

Go into the attic, rake aside the insulation, lay plastic vapor barrier, rake it back? Maybe staple cardboard to the underside of the roof? Sheets of cardboard on the floor of the attic, at the second floor ceiling? Anything has to be an improvement. I'm looking for ideas to save heat, but with low cost to the home owner.

[BobK207]

Where is the house?

You get most benefit from ceiling insulation, then walls, then floor but air leaks are more important than any of these.

How much (%) of the ceiling (via the attic) is accessible?

Low material cost? Or low labor cost? Is the guy gonna do the work himself?

IMO that loose whatever is more trouble than it's worth. Vacuum it out & start fresh.

Or once its vacuumed up you can bag it & re-deploy it later....raking away & raking it back over the vapor barrier sounds painful & tedious.

There are vapor barrier paints that can be used on the ceilings & walls with better coverage & performance than plastic in the attic.

Cardboard is not much of a building material.

cheers Bob

[Pat]

Frequently these houses have openings in the wall to porch overhangs and floor joists. Sometimes the walls are open at the bottom in the crawl space. Best way is to remove the plaster and install fire stopping. Might as well plumb, wire and rearrange interior walls while you are at it. A lot of work but material costs are low.

[Pete C.]

Blown in cellulose for the attic will be the easiest and cheapest most likely. While you could remove the crap that is there now, there will be little benefit. Just blow new cellulose on top and it will be fine. I just blew quite a bit of cellulose into my attic here and while I was working I was able to both feel the attic getting colder and the furnace cycles getting less frequent.

For the walls you need to *remove* sections of the AL siding to drill holes and blow in cellulose. Reinstall the AL siding after the insulation is installed and the holes capped. Expect to find lead paint and / or asbestos under the AL siding, not enough to worry much about for a handful of holes, but wear a mask and spritz with soapy water when drilling the holes.

Alternate for the walls would be to gut the inside, install regular fiberglass batts and vapor barrier and then sheetrock. Also provides an opportunity to fix other stuff in the walls, but is of course more work and expense, though not that much if DIY.

As already noted, hunt and kill all drafts you can find with expanding foam, caulk, weather-stripping, etc. as appropriate. I expect the windows are not very efficient, so anything you can do to help there should make a notable difference.

The 70% furnace is enough behind even the crappiest new furnaces in efficiency that it would probably have a pretty quick pay back if replaced. There are probably some utility and / or government rebates / subsidies / grants available to help replace it.

[Big_Jake]

That vapor barrier isn't important, as primer can be used as a vapor barrier in new construction. Not that I wouldn't use a vapor barrier in new construction, I just think you have "bigger fish to fry". Blown in cellulose in the attic, paying special attention to making sure you have "chutes" in place for airflow from the soffits up to the roof vents.

I think it is bad advice to remove all the plaster or the aluminum siding. We had a couple of rentals insulated by a pro, and they drilled a couple of holes in each stud cavity, and they blew in cellulose from the inside. Not exactly a DIY friendly way to go, but cheaper than most alternatives. Get more than one quote.

I thought you lived somewhere "warm" like Tennessee. As someone else posted, you have to weigh the costs against the benefits.

BTW, the type of roof you are talking about is a "hip" roof.

JK

[ransley]

Heat rises, the attic is easiest to do and gives the most benefit in energy savings. The 2.5" that you have now is maybe R 9. Your zones optimal is maybe R 50-60. Code for your area is maybe R35-40. Cheapest is Cellulose, but it soon settles 15-20%. Cardboard is maybe R .05, kind of worthless

[JoeSpareBedroom]

Heat rises, the attic is easiest to do and gives the most benefit in energy savings. The 2.5" that you have now is maybe R 9. Your zones optimal is maybe R 50-60. Code for your area is maybe R35-40. Cheapest is Cellulose, but it soon settles 15-20%. Cardboard is maybe R .05, kind of worthless

++++++++++++++++++++++=

Once again, you are replying to the wrong person.

[Big_Jake]

In an attic, it is easy to load the cellulose up so settling wouldn't be an issue. I have opened up walls with 20 year old cellulose in them that shows no sign of settling.

Where on the planet do you need R60? I am in Wisconsin, and R38 is code here.

JK

[Jim Elbrecht]

-snip-

The New York State energy code has areas that require 49. [over 6000 heating degree days] Most of the state is R38.

I'll bet the payback is fairly quick for that extra 10-15 R's [especially on blow-it-yourself cellulose] with energy costs where they are.

Jim

[Stormin Mormon]

Where is the house?

CY: Western, NYS, USA.

You get most benefit from ceiling insulation, then walls, then floor but air leaks are more important than any of these.

CY: Hmm. Air leaks -- so, maybe laying down thick mil plastic may be a big help?

How much (%) of the ceiling (via the attic) is accessible?

CY: Probably 80 or 90%. The roof has a very low pitch, and so the outer edges are too damn short.

Low material cost? Or low labor cost? Is the guy gonna do the work himself?

CY: Ideally both. The two of us figure to do the work.

IMO that loose whatever is more trouble than it's worth. Vacuum it out & start fresh.

CY: That's a thought. The loose crap would come up with a shop vac, but the blown in fiberglass ought to come up with a broom and dust pan.

Or once its vacuumed up you can bag it & re-deploy it later....raking away & raking it back over the vapor barrier sounds painful & tedious.

CY: If the loose stuff was in a pile, it could be replaced. Maybe thicker than it was, and then put something else on the other side.

There are vapor barrier paints that can be used on the ceilings & walls with better coverage & performance than plastic in the attic.

CY: You know, I'd never have thought about that. Vapor barrier paint.... neat stuff.

Cardboard is not much of a building material.

CY: yeah, but it's free!

cheers Bob

[Stormin Mormon]

Blown in cellulose for the attic will be the easiest and cheapest most likely. While you could remove the crap that is there now, there will be little benefit. Just blow new cellulose on top and it will be fine. I just blew quite a bit of cellulose into my attic here and while I was working I was able to both feel the attic getting colder and the furnace cycles getting less frequent.

CY: That's a thought. Makes sense to blow some more fluff on top of what's there. We also discussed a roof power vent fan for summer. Maybe some more insulation, and the heat wouldn't come down from the attic during the summer.

For the walls you need to *remove* sections of the AL siding to drill holes and blow in cellulose. Reinstall the AL siding after the insulation is installed and the holes capped. Expect to find lead paint and / or asbestos under the AL siding, not enough to worry much about for a handful of holes, but wear a mask and spritz with soapy water when drilling the holes.

CY: I've had a couple folks suggest to pull out a row of siding. I'm not sure it's flexible enough to tip up. We have discussed drilling indoors, and put some trim or something along the ceiling where we drilled. Molding, maybe.

Alternate for the walls would be to gut the inside, install regular fiberglass batts and vapor barrier and then sheetrock. Also provides an opportunity to fix other stuff in the walls, but is of course more work and expense, though not that much if DIY.

CY: There is one stretch of wall he's considering tearing out the lath and plaster, and then sheetrock. That would be the moment to put in fiberglass, and vapor barrier, and drywall.

As already noted, hunt and kill all drafts you can find with expanding foam, caulk, weather-stripping, etc. as appropriate. I expect the windows are not very efficient, so anything you can do to help there should make a notable difference.

CY: Thanks for the reminder, I've got some window plastic.

The 70% furnace is enough behind even the crappiest new furnaces in efficiency that it would probably have a pretty quick pay back if replaced. There are probably some utility and / or government rebates / subsidies / grants available to help replace it.

CY: That's a thought. Grant or subsidy. I installed furnace for six years, so the labor and technique isn't an issue.

[Stormin Mormon]

I think Ransley posts from a VA hospital mental wing.

[ransley]

Code may be 38 but is it optimal, no its an old code based on cheap energy costs, look into what it costs to heat a SIPs house, about half. For walls 2x6 and foam is optimal, but few want to spent the extra cash

[marson]

The key words seem to be "on the cheap". Can't even afford cellulose? Blowing cellulose is a pretty cheap way to insulate the attic. Obviously the walls are more screwing around. Blowing cellulose from the outside is preferred, but if that isn't practical, it can be done from the inside. Lots of patching and painting involved though. If you went that route, don't monkey with holes-- just demo a strip of plaster. Might consider pricing some vermiculite which you could just dump in the attic. Don't know how it compares to cellulose cost wise. I agree that a vapor barrier is not of primary concern here. Nor is it worth anyone's time to monkey with cardboard.

I recently tore the siding off of my 100 year old house and added an inch of foam. Made an unbelievable difference in the comfort level inside. Haven't seen a heating bill yet since I did it, but it would have to help.

[Stormin Mormon]

Yep, cheap is the operative term for this job. As to cellulose, the local store will loan out the blower, with the purchase of twenty bags. I did some insulation for my place, all of about six bags, as I live in a trailer. Used a couple other bags for the heated added room, at a friend's house. I'm wondering, maybe the cellulose blower is going to be the best answer, fill the attic up as best possible.

As to the walls, the exterior is aluminum siding. He's OK with drilling holes, and put some kind of trim wood or roll out a decorative tape of some kind to hide the holes.

I'd think that an inch of foam would work for both conduction and convection.

[Pete C.]

A power roof vent shouldn't be necessary if there are proper non-powered vents. Natural convection will move the heated air out just fine if there are ridge and soffit vents.

If you patch the holes with reasonable care, a wallpaper border strip up top and a taller baseboard at the bottom would cover the patched holes nicely.

Yes, most work, but more opportunity to fix stuff. Check plumbing and electrical while you're in there. Drywall, compound and paint are pretty cheap, only labor is expensive.

One thought on this is that there would be more benefit from a double install. With the normal install, you block drafts, but since you get cold air exchange on the window side of the plastic your only insulating value is the thin plastic itself. If you install one plastic layer as close to the window as possible and a second at the normal inside point you'll get dead air space between them which should add some R value.

There are a fair number of poorly publicized programs in most areas. Energy efficiency upgrade programs, senior assistance programs, etc. One flaw in many of these programs is a (union sponsored no doubt) requirement to use contractors vs. DIY and let the program inspect.

[Pete C.]

I blew in some 84 bags of cellulose in about 6 hours with the assistance of a friend feeding the blower unit while I crawled around the attic. Goggles, respirator and hard hat required.

If you're blowing into the walls from the inside be sure to plastic off other rooms since cellulose dust will blow around just as bad as drywall dust during the work.

If it's installed with taped joints it's also a good whole house vapor / draft barrier, and on a 100yr old house drafts will be a big issue.