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I live in a 100 year old Victorian in cold damp New England. The kitchen floor is pine tongue and groove that has over the years shrunk so that there are small gaps between the floor boards. I’ve been thinking about insulting the floor from the bottom side which is accessible from the basement. This wood hopefully seal up some of the heat loss to the drafty damp field stone walled basement. First, is this a good or bad idea. If a good idea, should I use a vapor vapor or not and on which side of the insulation? What type of insulation would be best – fiberglass, foam board, whatever? Thanks for the help.
Chuck
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Chuck,
FG insulation will merely filter the cold air before it enters your kitchen. Foam board would be a better choice. If you can, run it over the bottoms of the joists to make a monolithic air barrier. Gap the sheets out a tad and foam in bewtween them to seal up really tight. If that's not possible, cut the foam boards to fit between joists and foam the perimeter of each board to the joists and adjacent boards.
But you are only addressing the supply side of the equation. The demand side is even more important. A 100-year-old house is probably balloon-framed and probably has major air bypasses that allow your heated air to go flying out the top of the house, which is replaced by the heavier cold air pushing up from below to take its place.
Here's a more extensive explanation in a article I wrote a few years ago:
http://www.oldhousechronicle.com/archives/vol01/issue05/technical/weather.html
While there check out the site. All volunteer. They've done some fine work there.
Steve
*My wife and I recently purchased a home (colonial style) constructed in 1939. As typical of homes in our area there was no insulation in the walls, crawl space, or attic. There is also a major construction difference between this home and our previous home which had been built in 1919. The difference is the siding on our current home is nailed directly to the studs. There is no sheathing,tar paper, or moisture barrier of any type. The siding is non-back primed Bald Cypress (Taxodium distichum) and is in relatively good condition except it still has its original paint under all the later coats. The interior walls are USG Rocklathe (early drywall) with a skim coat of plaster. Of course every time the wind blows we can feel it throughout the house.We want to insulate but are uncertain as to the type or whether we should remove the siding and sheath the house first. If we pack the bays as they are now will we not create a moisture problem inside the walls?David
*David,I've wrestled with this particular dilemma with the homes in our area (central New York) where many of the 19th century homes have no sheathing. In my own house I've addressed it three different ways. 1) Where I've had to remove siding anyway, I've sheathed with plywood before re-siding and then blown with cellulose. 2) Where the siding was in good condition I opened the walls from the inside. In those instances, I tried two different approaches. In some areas I wrapped the inside of each stud bay with tyvek then installed fiberglass batts. These walls are still very drafty. When the wind is blowing I can feel the draft at the bottom of the wall. 3) More recently I've tried creating a drainage plane behind the existing siding by putting spacer strips of 1/2 inch plywood along the edges of the studs up against the back of the siding, then cutting a piece of foil-faced polyiso foam to fit between the studs, pinning it up against the spacers, then foaming the perimeter. Then I densepacked cellulose between the drywall and the foam board. One of these days I'll have to get some thermal imaging done of the different areas to see what they look like.I know this doesn't help with your situation. You want to be able to leave the siding in place and plasterbard in place. I know people who have blown cells into such cavities, but I don't know what the long-term effects would be. I myself am still not comfortable with it. I guess the real question is whether the rate of wetting due to leaky details in the siding would exceed the rate of drying. That would cause moisture damage.You might want to talk to Joe Lstiburek to get his take on it. http://www.buildingscience.comSteve
*Steve, do you think this might be a circumstance that justifies Iceneyne (sp?)?Andy
*Andy,I would think it would be worth investigating. How impervious to water is Icynene? I've read in other threads here that it is an open cell foam. Does that mean it can get saturated? And if so, what are the implications in this instance?David, What's your climate? Cypress siding leads me to believe southern?Steve
*Help! Me too. I just bought an 1875 Victorian and I'm also wondering about insulating the joist bays from the bottom and adding a vapor barrier. I'm hoping to find out the potential "cons" of doing this. I thank you in advance for your time and consideration.