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4 Answers

Improving R-value of 2x4 wall in renovation with interior foam board

Hi gang,

Doing a renovation in MA, USA, and I need a little help... There's a 2x4 wall that needs insulating, and I'm not redoing the exterior of the building. It would be easiest for me to get the wall dense-packed with cellulose, then go over the whole thing with 2" foil faced foam... but I have a couple questions...

Asked By Eric Nash | Sep 23 14
40 Answers

I am using Roxul insulation for ceiling and walls in a post-and-beam barn home

I plan to use this insulation in a 2x8 ceiling and 2x6 stud walls. Roof is sheathed in OSB, with a Titanium underlayment with standing seam on top. Walls have OSB and Tyvek house wrap. My question is can I use a poly vinyl vapor barrier on the interior after installing the insulation and then cover with 1x6 tongue and groove pine board. I have seen conflicting information on this. We are in Kansas which I think is Zone 6. This is a full post and beam barn structure. It has a gambrel portion with a loft. Loft has 12' high ceilings. Lean to portion has 9' high ceilings.

Asked By David Hauber | Sep 25 14
1 Answer

Lawyers, Engineers and Builders Oh MY!

A place to debate or kill some time

Asked By aj builder, Upstate NY Zone 6a | Sep 27 14
28 Answers

Options for high R-value above-grade walls (R-80)?

To make a long story short, my above grade exterior walls need to be at an R value of 80. This is to meet Passive House standards for a new residential house in a very demanding climate.

I am currently planning on using SIP's of some sort. But even the best of those only get me up to around R-50 though. Any thoughts on ways to get to R-80 while still being cost effective and keeping the size of the wall to a minimum?

I have found a number of options myself, but was curious if anyone else had thoughts or suggestions to meet such a high R value for a wall.

Asked By Tom Schmidt | Sep 19 14
6 Answers

Flash and Batt in Reverse - Modular

Working on a modular residential project in CZ 6. In modular construction though, the batt is installed on the exterior facing edge of sheathing and closed-cell spray foam on the interior facing edge of the gypsum (serving as vapor barrier). Would this flash and batt insulation in reverse cause any problems with moisture transfer?

Also, if we could, does it make sense to add an inch of Poly iso or Roxul on the outside of the sheathing as a thermal break to the outside to increase R value and add a thermal break?

Asked By Chris Parker | Sep 26 14
3 Answers

Old house with no sheathing/vapor barrier

I have an old house with no sheathing or vapor barrier, just clad siding on top of studs. I have the interior gutted and I am set to add batt insulation and new drywall back as it was originally. Should I add felt on top of the insulation and under sheetrock as a vapor barrier...still allowing the wall assembly to dry to the outside? or will it condesate on felt in summer and rot studs/etc.

ps I am in SC...really hot/humid.

Asked By charles elrod | Sep 25 14
10 Answers

Best place to buy rigid foam insulation?

In general, where have you found the best price on XPS and Polyiso? Lumber yard? Big box stores? Other? We are in the design stage of a new custom home project and I want to analyze price/performance as we are creating the plans. In the past I have relied on my stucco sub to provide it in his bid, but we will install on this project. Thanks for your input!

Asked By Bill Costain | Oct 11 11
4 Answers

Window coating confusion

I’m trying to figure the proper coating to order for my new windows for my renovation project, I was planning on triple pane windows from Ostaco windows. The house is located in Toronto, ON sits with the rear facing southeast, front northwest, the house has a fair number of large windows facing the rear, fewer on the front, no real tree shading in the rear, some red pines in the front, hoping to get wall insulation up to R40 range. The options are Low e 180 Low E2 272 and Low E3 366 all from Cardinal. Cardinal has a calculator for deciding but I would prefer input from others also.

Asked By Dave B | Sep 24 14
10 Answers

Has anyone worked with ISO from Insulation Depot?

Was wondering about experiences purchasing re-claimed insulation from the Depot. I can get a truckload of 3" full sheets of ISO. Will I need to cut new edges and will it be full of holes? They're finishing a job in Chicago the the price for shipping to Appleton, WI is good.

Asked By Paul Kuenn | Mar 27 14
11 Answers

Proper way to insulate an old attic?

I am helping to insulate a friend's attic in Milwaukee, Climate Zone 6. The house is 100 years old, balloon frame with stucco. Attic floor is lathe and plaster. We would like to remove the fiberglass insulation, clean the attic floor, seal holes/top plate, then spray 2" closed cell spray foam to air seal the lathe and plaster. After that fill in blown cellulose to R-60.

Asked By Justin Lee | Sep 23 14
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