Hi, I need advice on insulating my old house (105 yrs. old). There is virtually NO insulation in the attic at all. Between the joists you can see the lathe and plaster. There are scatterings of insulation here and there that is basically usless and likely should be removed (since critters have used it as a urinal).
My question is, if I put down batts of insulation, should I FIRST be putting plastic down as a vapour barrier. I think I read that some types of insulation comes with a built in vapour barrier on one side.
I thought that I would remove the old rotted insulation that is currently there, put in batts of fresh insulation then blow in more on top. Any suggestions
It depends a lot on where you are, weather conditions, home construction. This is especially true for the vapor barrier. It also depends on what indoor temperatures you wand and if you have AC or not.
Look at the venting & HVAC arrangements. Check the Building Science Corporation web site. I have a house from the 1840s in hot humid climate and insulated the roof rather than the ceiling. This has worked o.k. for 25 years. TB
the climate in my area is Canadian winter cold! So having a high R value is important. I do not want a toasty warm house, I prefer things a bit cooler, however, I do not want my heating dollars going out the roof either.
the climate in my area is Canadian winter cold! So having a high R value is important. I do not want a toasty warm house, I prefer things a bit cooler, however, I do not want my heating dollars going out the roof either.
the climate in my area is Canadian winter cold! So having a high R value is important. I do not want a toasty warm house, I prefer things a bit cooler, however, I do not want my heating dollars going out the roof either.
You can purchase insulation that is unfaced (no vapor barrier), faced on one side, or faced on both sides. If you buy the single faced insulation, there should not be a need to put down a separate barrier. I have never used the double faced in any application, but would be wary of it in an attic where you need the insulation to be able to "breathe."
Removing the old insulation is probably a good idea. One never knows what has lived in it, especially over a hundred year span.
If you place bats into the troughs between the ceiling joists, be sure to place the barrier side down. Do not pour insulation over the bat material. Insulation depends upon trapped air to provide the heat transfer stoppage between two spaces. Placing a poured material on top of the (I am assuming fiberglass) will crush the fiberglass and reduce its designed air volume and thereby reduce the efficiency of the material.
If you really want to add to the "R" value of the insulation, and don;'t mind a lot of work, you can cut slabs of Styrofoam insulation to fit be between the joists and lay that in before putting in the roll material. In this scenario, the independent vapor barrier would be advisable and unfaced bat material on the top. Again, do not put anything on top of the Fiberglas that would crush it down.
Singe sided bats. If there really isnt too much of the old stuff remove it. If there are animal dropping etc, take care of that first.
Then seal up and electical holes that you may have. What I mean by that is high hat or outlet drops that are in the ceiling.
If you do have highhats up there make sure that they are rated to be up against insulation. If not, the need to be simply boxed in. (no need for any fires up there)
Do NOT insulate the roof!!! This can create an icedam situation. This may work for warm weather areas, but you are in canada. If your into doing all of this, go to one of your local home centers and simply ask for help.
One thing that I certainly recommend if you do this is that you get decent dust masks (respirators) when playing with this stuff. No need killing yourself while saving some money! Long clothing also helps releive some of the itch factor.
I would measure the distance between the joists in several places. If it's anything like mine, then you'll want to use the blown in variety to to inconstincies on the spacing.
I agree about removing what is there under those conditions. However I don't recommend batts for this use. Blown in insulation will provide some vapor barrier and will help seal air leaks that are likely to be plenty. I would not use plastic as I have heard of too many situations in these old homes that doing so ended up trapping moisture where it caused problems.
I'll say it. Batts suck in Canada in the attic. Why waste your time? Blown in is better. Cellulose, of course. Foam is even better, but pricey. I have a definite grudge against fiberglass. In case you haven't noticed.
Why? see
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- but that's another story...
If you do use foam or cellulose, either a contractor or a do-it-yourself spray foam kit, be careful you or they don't block the eave vents if you have the "eave vent to ridge vent" configuration or, as someone so wisely stated, you'll have a potential problem with ice dams if the seal isn't complete and moist air gets up into the attic from the living area.
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