nash Posted September 14, 2018 Report Share Posted September 14, 2018 I have paper back insulation in my cabin and it is of low R valve. I would like to insulate over the existing insulation without all the hassel of removing the old paper type. Could I simply make cuts in the paper to let it breathe or do i have to take it all out. or do nothing . thanks Quote Link to comment Share on other sites More sharing options...
TimK Posted September 14, 2018 Report Share Posted September 14, 2018 18 minutes ago, nash said: I have paper back insulation in my cabin and it is of low R valve. I would like to insulate over the existing insulation without all the hassel of removing the old paper type. Could I simply make cuts in the paper to let it breathe or do i have to take it all out. or do nothing . thanks Best practices of several energy programs recommend removing vapor barrier(s) from between insulation layers so that moisture doesn't get trapped adjacent to building materials. Therefore it depends on where the "paper" is located. If it is in an attic and the paper is on top, it is incorrectly installed already and should be removed. If it's against the ceiling, it's fine. From the way your question is stated, I suspect the former is the case? Quote Link to comment Share on other sites More sharing options...
TimK Posted September 14, 2018 Report Share Posted September 14, 2018 Best practices of several energy programs recommend removing vapor barrier(s) from between insulation layers so that moisture doesn't get trapped adjacent to building materials. Therefore it depends on where the "paper" is located. If it is in an attic and the paper is on top, it is incorrectly installed already and should be removed. If it's against the ceiling, it's fine. From the way your question is stated, I suspect the former is the case? Quote Link to comment Share on other sites More sharing options...
nash Posted September 14, 2018 Author Report Share Posted September 14, 2018 its a open ceiling cathedral framing. the paper is backed to the interior and done as a vapour barrier. but if i cut slits into to it then air can exchange and no moisture....am i right or wrong to think this. Quote Link to comment Share on other sites More sharing options...
John Kogel Posted September 15, 2018 Report Share Posted September 15, 2018 (edited) Slits will work, and the best vapor barrier is poly sealed with tape. In my climate, we are required by code to seal around electrical boxes with poly covers or use boxes with built-in gaskets. Keep indoor air out of the rafter cavities, and provide air circulation of the cavities and you will have no issues. Soffit vents and ridge vents. You can form a bag around an electrical box from a square piece of 6 mil poly. Make it large enough to have several inches hanging all around the box. Tape around the wire. Then when you staple up the vapor barrier, cut a small hole and pull your bag edges out, trim and tape. Edited September 15, 2018 by John Kogel Quote Link to comment Share on other sites More sharing options...
Perfect Home Inspection Posted September 25, 2018 Report Share Posted September 25, 2018 Hello, Can foam insulation work in this case? Quote Link to comment Share on other sites More sharing options...
John Kogel Posted September 26, 2018 Report Share Posted September 26, 2018 21 hours ago, Perfect Home Inspection said: Hello, Can foam insulation work in this case? You would not see foam sprayed over existing batts. Certainly with the batts removed, foam makes an excellent seal. One concern is there can be a lack of air circulation between the foam and the roof sheathing. Maybe it is not a problem as long as there is no moisture trapped in there. Foamed attics are still fairly new in the scale of things. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.