Replies

1. GBA Editor
   马丁·霍拉迪（Martin Holladay）|Oct 13, 2016 01:38pm|#1

   Tim,
   You don't need sleepers over the rigid foam installed on the slab. The T&G plywood or OSB is just fine -- in fact, it's a better approach, because it allows for thicker foam. Here's what I wrote on the topic in an article titledFixing a Wet Basement:

   “通常的技术是在现有混凝土的顶部安装1或2英寸的XPS或EPS泡沫绝缘材料，然后将一层胶合板固定在泡沫上，然后用Tapcon紧固件固定在混凝土上。（如果您仍然担心，您的平板有时可能会潮湿，您可能需要在泡沫下安装一层Dimple垫。与混凝土联系。用高质量的欧洲胶带，带填缝剂或罐装喷雾泡沫密封每块泡沫绝缘的边缘。

   “有关绝缘现有地下室板的更多信息，请参见：
   Finishing a Basement Floor;
   Green Basement Renovation;或者
   呆板，未完成的地下室。”

   .

   When it comes to walls, you are correct. You don't want to insulate the basement walls on the interior with fiberglass batts. For information on the correct approach, see this article:How to Insulate a Basement Wall.

2. Expert Member
   Dana Dorsett|Oct 13, 2016 03:33pm|#2

   由于XPS随着时间的推移而降低了EPS的相同性能，因此您最好使用1.5英寸的EPS，该EPS使用100倍的良性吹式剂，并且每个标签为r的价格更便宜。夏季露点控制点在地板/泡沫边界处有足够的范围。

   2 x4 / R12 studwall只值bout R8.5-R9 after factoring in the thermal bridging of the studs. That's fairly pathetic performance for a zone 7 climate- int wouldn't even meet code in zone 4 under IRC 2015. Continuous 3" of EPS held to the wall with 1x4 furring through-screwed to the foundation delivers about R13 in a zone 7 climate, and takes up only 1/4" more depth than a 2x4 wall. With all of the moisture-susceptible wood on the warmer interior, no interior poly is needed.

   Putting sheet poly on the interior traps ground moisture in the studwalls. You might be OK with 18" of above grade exterior exposure for a drying path to the exterior, but it's risky.

   If you expect the inspectors to complain with a furring + foam solution, put the poly between the furring and the foam, or use foam with plastic or foil facers. At 3" 1.5lb density "Type-II" EPS is already under 1 perm, and would meet Canadian code definition as a "vapour barrier", but that requires producing the spec and educating the inspector.

   Trapping foam to the foundation wall with a 2x4/R12 studwall would be even better. With 2.5" of EPS (R10.5) you have sufficient dew point control at the foam/fiber boundary to skip the interior polyethylene, per the prescriptives in TABLE R702.1.2 :

   http://codes.iccsafe.org/app/book/content/2015-i-codes/2015%20irc%20html/chapter%207.html

   That would deliver a whole-wall R of about R20, which is still appropriate for your climate albeit higher than IRC code minimum (R15 continuous insulation.)

3. 
   Tim Brown|Oct 14, 2016 04:53pm|#3

   Thanks...I'll forward that info...