[leone184]

Good point about cleaning the bricks with muratic acid. The Drylock company does make a masonry sealer/conditoner that will stabilize the surface & keep the salts from coming out, but the existing paint will have to be removed first. If the efflorescence is bad enough, most of the paint may be coming off already. A stiff scrub brush and lots of water may be all you need. If you get to that point, make sure you let everything dry out completely. If you decide to use the Drylock, be sure to get the acrylic latex version, (they also make a solvent based) it won't trap moisture inside the masonry, and is very paintable.

For the gap, most caulk companies make a butyl-rubber foundation caulk. It's waterproof, and will expand and contract with the changing temperatures. If the gap is very deep, consider stuffing a length of polyurethane backer inside, then put the caulk over that.

leone184