Insulation in old house in damp climate?
After years as a builder, I’m just starting to dig into remodeling my first house as a homeowner, and facing some insulation/air sealing questions. It’s a 1926 house, with (good condition) 10″ cedar lap siding over builder’s paper. I’m pretty sure this was installed in the 50’s or so, and it’s mostly over shiplap. Most of the walls are wood sheathing inside and out, but a couple of the rooms we have gutted to the studs. So, some insulation will likely be net and blow, and some existing walls will be drill-n-fill. We’re considering spray foam for the attic and floors, but we’ll see how much money we’ve got left over when we get to that point.
So, my question is, what do I use for insulation, and what should I be doing about air infiltration and vapor barrier? We live in western washington (wet for much of the year, rarely below freezing.)
Any good resources out there (books, websites) for info on this?
Replies
I'm getting closer to needing to decide on the material to be used in the open walls; our regular insulator prefers dense pack fiberglass, but it seems like most around here prefer cellulose. Is the cellulose really better at stopping air infiltration? My insulation guy claims the FG is just as good.
What does he mean by "dense pack fiberglass"? If he means blown-in small FG particles (sometimes call "BIBS" - blow in blanket system), where the fill is complete with no voids, then it likely would insulate as well. If he means just a high-density FG batt, then the cellulose will be better, because only you would take the time to really cut and fit the batts around all obstacles so as to have no voids. The contractor wants to get it done fast and be paid & gone.Edit: you provided no profile info. Where is your "damp climate?"
Edited 10/28/2009 5:28 pm ET by DickRussell
He is proposing a "net and blow" system for the open walls, and drilling and filling existing walls with the fine fiberglass particles. I'm definitely not interested in batts. This is basically the same system as dry pack cellulose, but a different material.
I'm in western Washington (Bellingham.)
Does your insulation guy ALSO installed dense-pak cellulose?If he does not, then he is likely just recommending what he sells.Personally, I'd rather have dense-pak cellulose.
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
IMO, either foam or cellulose.
other good sources of info;
old house journal's site (plenty of experience and differing views)
and buildingscience.com the reigning champ of real knowledge....
"Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary."
Reinhold Neihburh: 'The Children of Light and the Children of Darkness'
http://rjw-progressive.blogspot.com/
Spray foam for the airseal, and then dense pack cellulose. Check the window installation for air blowing in, and definitely check flooring for more air coming in.
Also, as was mentioned, check building science. com. They have a LOT of information there....sometimes it seems too much.
http://www.buildingscience.com/index_html
Lots of luck...its a big job....I'm there, doing that here in central Iowa!!
Dick
Thanks for all the suggestions. The Building Science site is excellent. Here's what I'm leaning towards: 1. Seal up the obvious holes in the walls with foam (prob cheaper to have insulation guys do this than with cartridges for my foam gun), dry dense pack cellulose in the walls. (net and blow for the open walls, drill and fill for existing walls.) 2. Roof: 1-2" foam for (unvented) roof, followed by 5" of cellulose. Someone suggested FG batts, as air sealing will be done, but I'm not sure if this is as good as cellulose. About half of the roof is EPDM with 2" of foam under it already, so I'm considering that sealed, and will just do 4'6" of cellulose under that.3. Crawlsace: This is where I still have questions. I'm considering "DrySpace" vapor barrier liner. It's a 12mil vapor barrier, and you end up sealing up the crawl space, leaving it unvented and heated. Seems like a good idea on paper, and I can buy the materials for $900 or so. Sounds like the theory is that you insulate (spray foam) the stemwalls, mudsill, and rim joist. I guess at some point the vapor barrier connects to the spray foam, and you've sealed it up. Do you do anything to insulate between the ground and the membrane? Anyone have any experience with unvented crawl spaces? http://crawlspaceinfo.com/DrySpace_Vapor_Barrier.htm
Edited 10/29/2009 6:39 pm ET by porkchop