Sealing the outside of a single brick wall

I have a single brick enclosed area under my house I want to turn into rumpus/bathroom. Instead of building a concrete nib and having a 50mm gap from the framework of new wall to the existing single brick wall, could I perhaps use some sort of brick sealant on the outside brick walls? This way, I could just fix the wall frames straight onto the brickwork.

I believe they are spray on water sealants.

Here's one I found. Would this do the job?

http://www.cavalcadecoatings.com.au/docs/Gardall%20Brick%20Sealer%20PDS.pdf

Would this method get approved by council?

Cheers

Ben

EDIT: Found another product... http://www.crommelin.com.au/images/n...r%20Sealer.pdf