We are getting ready to finish our basement (a walk up) and were planning to use the ‘mold proofing’ technique with XPS from the FHB issue last year sometime, and the guidelines at http://www.buildingscience.com/resources/foundations/renovating_your_basement.pdf I really wanted to read the FHB article again for more details, but now I can’t find it anywhere, and I have to add the XPS to the materials order tomorrow (Thursday delivery). Has anyone done this before? What thickness of XPS did you use, how did you affix it to the walls, and how did you tape the seams? Once you framed the walls on top of the XPS, did you use fiberglass bats between the studs as well? We were thinking of using 1- 1.5″ XPS, then framing and possibly using the fiberglass insulation too. Once we added it up, the XPS seems pretty expensive, though, but I really do want to use it. Our other concern is that if we go too thick on the XPS we will lose the extra few inches all around and throw our measurements off on our plans. On the other hand, I really hate the idea of using and working with fiberglass if I don’t have to (not to mention the additional cost and time).
For the floor, I think both of those resources talk about using the XPS on the floor too. How did people handle the floor- is using it there really important? We have a pretty low clearance, so we don’t really have a lot of room for doing stuff on the floor. I was actually considering using the dri-core, but we haven’t decided.
Any experience or input that people have would be appreciated! Thanks.
Kirsten
Replies
I don't know where you live, but it could be a factor in the insulation thickness on the walls.
For the floors use 1" XPS. The article recommends EPS, which I have used on the floor, but it is too springy for my taste. 1" XPS has sufficient vapor permeability for use on the floor according to Building Science.
On the walls use at least 1" XPS -- if you have the space go to 1 1/2".
You can use Tyvec seam tape or a similar product for the seams. Don't use duct tape...
There's no need to use fiberglass unless you really need the additional insulation value.
You can affix it with PL polyurethane construction adhesive.
Read and re-read the articles. Pay attention to the details -- rim joists, etc. Maybe you need to sit down and go through everything instead of rushing your materials order.
Billy
I live in the DC area, so although it gets cold in the winter (and hot and humid in the summer), we don't have tremendous extremes with the weather.
I did see both XPS and EPS discussed in the Building Science articles, but I really wish I could re-read the FHB article too since it has lots of good pics and more details. But, I can't find it anywhere. Anyone know if there's a way to (pay to) access a particular issue or article directly online?
I will go back to the Building Science article and see what other details are in there. Anyone else have advice? Unfortunately, we can't wait to place our materials order because we've got people coming this weekend and next week from out of town to help us with the project. We've just been so busy with our other projects that some of the details for this one have slipped....
There is an online archive that you can buy back articles.http://www.taunton.com/store/fharchive/index.aspHowever, don't think that it has been updated with last years articles.I could not find it. The author was Andy Engel and using that and also keywords did not find it.It was in issue 169, march 2005http://www.taunton.com/store/pages/fh_toc_169.aspI did one about 2 years ago and used 2" of XPS and like the results.Also about 20 years ago I did one with 3/4" EPS and later covered about 1/2 of it with 2x4 walls with FG and have not had any problems. But that is a completely different type of usage as it is not under a house, but rather a garage so there is little internal moisture problems and about 1/2 the wall is exposed on the outside.