Nowadays we'd use an epoxy sealant and/or plastic sheeting...

I emailed him about it after I searched the work and the time between coats and he said he used a dry torch for the sealant or whatever it's called and said he performed work that should have cost me $14k.

Applying a sealant product to any framing members (joists and studs) after the chemical treatment will probably also be a good idea to follow.

This is easy to do with off the shelf sealant and an applicator.

It needs minor cosmetics and possibly a basement sealant.

One leak is often a popped nail, or a shingle either loosened or blown off in a windy storm or perhaps a leak around a chimney where the sealant has cracked a bit...or the cracked boot.

The color and gauge can also create buckling.Scratches due to walking on them should be touched up to prevent corrosion, salt laden environments will exacerbate corrosion.Improper fastening can create leaks, as well as poor quality/applications of sealants used during installation. 

Excessive wear to painted surfaces outside of what would typically be expected.Faded/mildewed caulking, silicone or other sealants around the bathtub, tiles, sinks, countertops, vanities, etc.Missing caulking around the bathtub and tiles, excessive mildew or water damage, unreported issues potentially.Hard water deposits or stains in sinks, tubs, showers, etc.Buildup of dirt, mold, mildew, or water stains from a preventable or unreported water leak or drip at a fixture or in wet areas or water damage to hard surface flooring resulting from unreported leak or issue.Worn out or deteriorated finishes on deadbolts, locksets, handle sets, loose or stubborn door locks, loose hinges, handles, cabinet pulls, knobs, etc.Broken, lost or unreturned keys, broken door locks, hinges, handles, cabinet pulls, knobs not resulting from normal wear and tear.

This may be good enough for our purposes here, but according to EPA these sealants tend to wear out a few years down the road and radon will creep up again even though the makers and sellers of these products state it's a permanent fix.

They use silicone sealant to seal gaps.