10:27PM | 01/09/14
This is going to be difficult to describe. We have an upstairs bathroom, the wall with the vanity and sinks faces what would be an outside wall but it is underneath the garage roof. The BR also sits partially above the garage.

We had a frozen pipe (has happened a few times) and one finally busted. Once the plumber cut the hole to fix the leak I could finally see what was in there. There is no real insulation in the cavity. There is the exterior wall then a gap then the interior wall which is insulated.

I want to insulate the area better where the pipes run through but I am not sure the best way to do it. My thoughts so far are:

(After patching the hole of course)

1) Spray foam the cavity - Cons cost and I don't know if this would be a problem since the interior wall is insulated. Would also have to put some kind of block between the floor batting insulation and the foam where they would meet.

2)Spray foam the outside of the exterior wall - Cheaper but would this be enough and again would it be OK since the interior is insulated. I think it would since there would still be an air gap between the walls.

3)Blow in cellulose insulation. Cheapest option, but would it be enough plus there is always settling that occurs, maybe combine this with spray foam on the exterior.

4)Some other solution I am missing.

I am attaching one picture I have of the repair which kind of shows what it looks like inside. The exterior wall is just plywood with tyvek on it.

Duane, Moderator

11:10PM | 01/09/14
Member Since: 11/14/13
87 lifetime posts
It appears you could have 2 problems, one of course as you noted you have plumbing pipes in a unconditioned space and that needs to be corrected. You typically need to install insulation against a ridged air barrier ( outside wall) The issue becomes a dead air space between the outside wall and the existing interior insulation. I can not tell you for sure ( the picture helps but I can not make a determination by it) 1 possibility is to spray foam the entire area to insulate and to take away any air barrier between outside wall and interior wall. This should stop the freezing and the air infiltration that is possible in that area. I would however suggest you have a insulation expert visit the job site and make a determination. You will want to be careful as you do not cause conditions for mold.

Duane, expert moderator


Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.


type the code from the image


Post_new_button or Login_button

Colorful, useful, and fun, these tire planters form the foundation for a delightful container garden. Just spray-paint old... Reused steel windows create an eye-catching splashguard in this walk-in shower. The vintage factory windows bring an inter... A galvanized steel tub is a surprising but charming fixture in this bright and breezy screened patio. It's perfect for was... If you're not crazy about the idea of commingling plants and pool, this modern variation may be more to your liking. The s... Yes, a freestanding garage can become its own tiny house. Artist Michelle de la Vega has all the comforts of a modern resi... If you lack plumbing skills but have a good sturdy tree, here's the easiest outdoor shower solution of all: Simply attach... Pursue what's known as the stack effect. To achieve it, open the windows on both the upper and lower floors, and as warm a... How do you like this smart use for an old bottle? Clamp an empty wine bottle to a fence or wall near your outdoor deck or ... Simple and striking, a couple of pieces of "lovingly used" furniture creates a special kind of charm. A weathered chair fo... Twine lanterns add pops of crafty—but sophisticated—flair to any outdoor setting. Wrap glue-soaked twine around a balloon ... When securely fastened to a tree or the ceiling of a porch, a pallet and some cushioning make the ideal place to lounge. V... Incorporate nature into your lighting scheme by securing a dead tree in a concrete mold and draping your pendant lamp from... For the cost of a can of exterior paint , you can totally transform your porch. Paint the floor a hue that complements yo... In this urban apartment, a standard-issue patio became a serene and green perch by replacing the typical concrete with gro... This garden shed has been decked out to the nines. Designer Orla Kiely created the intimate home for a flower trade show, ...
Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon