How can I resheathe behind brick fascia without removing the brick?

by Karl Katzke   Last Updated September 13, 2017 13:21 PM

The original builders of my house used a material called "Aluma Sheath", also known as Dennyboard, to sheathe my house. Dennyboard is a radiant coating on two sides of a 1/8 sheet of a fiberous material similar to what pegboards are made out of. It disintegrates when it gets wet and is very susceptible (and seemingly quite delicious) to insects, which eat out the core and leave nothing except the sheet of metal or mylar that's not thick enough to be used as tinfoil. It obviously was never providing any lateral rigidity, so in theory none should be required now although it is called for in code.

In the past thirty-two years, the Dennyboard has rotted as it was exposed to the elements. There was no tarpaper, housewrap, or other material between the Dennyboard and the brick. So I'm left with brick, which while a decent and fireproof rainscreen, is decidedly not waterproof, and there exists (many,many) ways for insects and moisture to directly access the insulation and sheetrock layers of the building envelope.

Is there a good and code-compliant way -- and barring that, just a good way -- to rectify this situation WITHOUT REMOVING THE BRICK OR INTERNAL STRUCTURE? My current concept is not code compliant as far as I'm aware. (It might be, but I don't have the experience to know.) I am planning to remove all of the sheetrock and insulation in the affected rooms, cut the brick ties (most of which are rusted anyway) after supporting the fascia from the exterior, slip housewrap between the studs and the fascia, and then slip a sheet of 4x8 1/2" (or less, I think I saw 1/4") of extruded foam sheathing between the studs and the housewrap. The entire thing will be re-anchored and affixed from the outside using CTP Grip Ties or a similar product. This should provide a watertight, sheathed, and even (insufficiently) thermally broken envelope without having to do any tearout work beyond the sheetrock.

Can anyone comment on the legality or feasibility of this idea? Tearing down the brick fascia is not possible; I'm very hesitant to alter the structure of the house in any way without getting a lot of (expensive) engineering advice first. Note: I have not begun tearout of the drywall yet and won't until this winter; the assumption that the brick ties are mostly rotted is because the fascia moves pretty freely and after doing a bunch of work to the roof and trim above this area I got a good look down inside between the fascia and the internal wall and saw the rotted dennyboard.



Answers 3


"Is there a good and code-compliant way -- and barring that, just a good way -- to rectify this situation WITHOUT REMOVING THE BRICK OR INTERNAL STRUCTURE?"

No.

"I am planning to remove all of the sheetrock and insulation in the affected rooms, cut the brick ties (most of which are rusted anyway) after supporting the fascia from the exterior, slip housewrap between the studs and the fascia, and then slip a sheet of 4x8 1/2" (or less, I think I saw 1/4") of extruded foam sheathing between the studs and the housewrap. The entire thing will be re-anchored and affixed from the outside using CTP Grip Ties or a similar product. This should provide a watertight, sheathed, and even (insufficiently) thermally broken envelope without having to do any tearout work beyond the sheetrock."

Your plan sounds like it could work, (except for the challenge of slipping 4x8 sheets of anything between studs and your bricks).

As a suggestion, I would use diagonal metal strapping for lateral brace across the studs if you are not using structural sheathing (i.e. foam).

See this article (goto page 2) and below image from finehomebuilding.

http://i.stack.imgur.com/r5AGo.jpg

ryanwinchester
ryanwinchester
February 12, 2013 23:02 PM

There is but one sane option in this situation: remove the sheetrock and insulation, then spray foam into the cavities up against the backsides of the bricks, essentially creating a rigid monolithic foam structure that envelops the studs and joins everything together. It will seal out moisture perfectly and also grip the bricks, becoming essentially a new wall of brick ties. This will solve the stated problems as well as hugely increase the thermal comfort of the house, but it won't be cheap. Make sure you use closed cell spray foam, as it is stronger.

I'm not a big fan of spray foam in general but the product is a good match for this unusual situation.

iLikeDirt
iLikeDirt
August 25, 2016 01:55 AM

I recently was part of an inspection audience for A Flood Safe presentation. Part of they're procedure was to fill the wall with a cementacias slurry between the brick and sheathinand creating a water resistance solid masonry wall. They were only able to go the 3 ft as any taller would require substantial structural reinforcement. This is also part of they're "flood safe" process.

Tony Cavaliero
Tony Cavaliero
September 13, 2017 12:21 PM

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