As some of you may have seen some of my other post on bathroom remodeling I have taken down some of the walls and see there is no insulation. My house is a block construction with a brick veneer with furring strips on the inside. I have read some of the documents from the Building Science group and I am not sure if I should use a vapor barrier and or which rigid foam panels to use?

My plain was to cut to fit rigid foam (not sure yet which one) to fit between the furring strips, use caulk and or that Greatstuff can foam to fill in the gaps and then tap off any other spots to make sure everything is sealed.

Since I have the concrete block and brick exterior I'm now not sure if I should put up the vapor barrier to allow the bricks to breath to dry out from any moisture. Is this needed for a more Northern climate?

Thanks

Common construction on better houses in the 50's around here. Every 5-8 courses had a row of brick that connect the brick and block. Not a brick veneer as most know, but what I call a full thick brick wall. 4" block and 4" brick, interconnected.

What I usually use is 2" pink foam with notches for furring strips. Glue the foam to the wall, screw the furring strips to the block with tapcons. Then hang drywall to the furring strips. Considerable improvement, but not all that much space sacrificed as with a 2x4 wall.

Insulation makes a big difference with masonry walls,
but it's tricky to get it right. Read up all you can.
Here are a couple of refs:

http://www.buildingscience.com/documents/reports/rr-0910-measuring-impact-interior-insulation-masonry-walls-cold-climate

http://www.greenbuildingadvisor.com/blogs/dept/building-science/insulation-retrofits-old-masonry-buildings-building-science-podcast

You have two main hazards:
--wet outer wall trickling in, sun driving moisture inside
--the usual condensation

If you can get some polyicynene spray foam (the type with
much more vapor permeability than polystyrene) you get
a good air barrier but the ability to dissipate moisture.

More foam is good in the cold, but watch out for
'heat bridging': cold from the masonry could telegraph
through your wood strapping, condense, and rot. A little layer
of foam under the strapping breaks this circuit, especially
of your go thick.

Sealing the outside with a flexible sealer is key to keeping
rain from sneaking in. With stucco a real drainage plain
like tyvek can be slipped in.

JimTheTinkerer

Sorry my terminology on the outside brick was wrong. Not sure if I can go with a 2" foam board I will have to measure if it will change my dimension for my new tub. Currently it has 3/4" furring strips. The walls actually didn't feel that cold compared to our last house that had plaster walls not drywall like this one. I figure something is better than nothing.

The water in the brick(s) is what has me worried about putting up a poly plastic vapor barrier or not?

I think whatever rigid foam board I use I will glue it with vertical glue lines so hopefully if it does build up condensation it can drip down.

Any particular board type to use?

Since it's a tub area you will have two seperate layers..
check the lit, but you likely want to "dry in" towards the tub
and 'dry out' for the outside. So you would have tile, foam
(w/maybe 3/8 foam under the furring), and a 6-mil poly barrier,
then the masonry and the outside. The masonry wets+dries
on the weather side and the tub surround wets and dries inward. The barrier between prevents the sun or weather shifts from driving the masonry moisture into the house,
so that's a hard barrier (the 6mil poly).

A tile surround needs the special mortarboard under it,
but a fiberglass surround you can have an airgap behind, and
there's no special drying path...

I am going with a Sterling tub/surround so I would not need a vapor barrier to help keep out water from the shower area. One short side of the tub/surround (3' section) is on an outside wall.

So a 6-mil poly barrier IS suggested using a rigid foam board like owenings XPS stuff?

Just want to be clear before I guy buying stuff which should be by this weekend.

Ah...in that case the 6-mil doesn't matter much,
unless the masonry is suspect (of getting soggy sometimes).

From what I can tell there doesn't look as if there has been any signs of moisture.

It looks as if I can just seal up the rigid foam board good with caulk and tape and I should be fine. There wasn't any type of vapor barrier there before so if anything the walls should be a little more insulated.

Unless someone else has a reason to put up a 6-mill poly barrier?

It could protect the furring,
but if you have a little air gap that should
help dissipate occaisional concentrations.

I gotta line my shower/tub with a molded thingie...
I had 70's type gypsum/tile I fixed w/construction adhesive.
Looks good, but under a 3-mil poly curtain. Without the
curtain the wall would have turned to porridge years ago.

I don't know if this is a good way to think about using the 6-mil poly just around the tub/surround area but I was thinking if it were to ever leak with out the poly I should hopefully notice it some what fast. Where as if I had the poly around the tub/shower it may help "hide" a leak for a long time.

As for the one small 8' exterior wall. I'm sure I'm not going to get all the small holes filled with caulk/Great Stuff can foam so that should leave me that "air" gap if I really need one.