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b1jackson
How to save heat loss in basement of old house

Hello folks, first time poster so I will try to be detailed and specific with my question. I just had a thermal scan done of my 120 year old house and I have a wicked amount of heat radiating from my basement. The basement has a cement floor and is heated. The foundation from the bottom to about 4.5 feet upwards consists of sandstone blocks about 10-12 inches wide. On top of the rocks up another 2 feet of so are hollow cinder blocks and then the large 12 inche wide wooden sill. Ground level would approximately be where the cinder blocks start.

Since the cinder blocks are pretty much high, dry and exposed, any amount of water I get in the basement comes in the form of seeps through the porous sandstone blocks (mostly down low). Not a major amount of water ever comes in. What I plan on doing is bringing a 2x4 stud down from the top for a length of about 5 feet. This will take me 2 feet below ground level and onto the sandstone. I plan on putting R-20 bats in between the studding. My main question is, what should I used as a barrier to drape down against the cinder blocks and the 2 feet down I am going onto the sandstone blocks? I want something that will keep the bat insulation dry and functioning in the odd time that dampness will occur and I don't want issues with sweating or mold formation. The reason I am using bat insulation vs. simply gluing on rigid foam, is that I need something flexible. With the cinder blocks being about 8 inches wide and the sandstone being another 4 inches out from that, there is no way with out major air space to make this work. Will a heavy layer of poly 5 feet down suffice to drain any dampness?

I by no means am looking for a perfectly finished gyprocked basement. I simply want a 5 foot insulated section around my sill and covering this cold and exposed section of wall.

Any help or suggestions appreciated. I have looked at Tyvek drain wrap, but don't know if I am waisting my money when poly would suffice?

titleist
Re: How to save heat loss in basement of old house

If you are just looking at insulation alternatives, I would suggest considering a foam board insulation. It is available in many thicknesses. It sounds like you understand this is not a complete solution since you are not insulating the entire height of the wall.

Hope this helps.

b1jackson
Re: How to save heat loss in basement of old house

No that doesn't quite answer it. I have room for a much better insulating layer (such as an R-20 bat) for most of the wall and a R-12 bat on the sandstone below grade portion. My question is, what type of barrier should I use against the foundation wall? Again, I am only making a 5 foot wall of insulation around the basement. Should I make an sort of insulation sandwich with vapor barrier on either side of the batts or do I want to leave the inner side open with just sheathing covering it?

b1jackson
Re: How to save heat loss in basement of old house

Ahhh, a picture is worth a thousand words. I've sketched in red the placement of the vapor barrier or some other barrier against the cold and occasionally damp basement wall (cinder block and sandstone. Will a heavy poly vapor barrier suffice here?

I have room for R-20 bats in between the wall and the 5 foot stud hanging from the ceiling on the cinder block portion and room for a R-12 bat on the lower sandstone portion.

Any advice on my vapor barrier requirements? Is standard vapor barrier going to suffice? Do I also need to place in on the inside (kinda making an insulation sandwich with vapor barrier as the bread??:D

canuk
Re: How to save heat loss in basement of old house

b1jackson .... here is a link to a product known as Platon which may be just the answer to your issue.

http://www.systemplaton.com/moisture_control.html

Hope it helps.:)

Re: How to save heat loss in basement of old house

Good stuff you don't want to sandwich and not have a point of exit for moisture.Your exterior should have a vapor barrier from the outside.If you line the wall any moisture trapped will condense behind the plastic.Water needs to dry either in towards the building or not get in at all.You do want to seal air infiltration,which are from gaps or cracks.

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