Sealing concrete garage panels?

[Jane]

We have a concrete sectional garage. This was sealed by the supplier with what looked like sand and cement which quickly came detached from the concrete base and leaked.

We have resealed about 18 months ago by first painting the base with pva then adding a sand cement mortar mixed with pva at a 45 degree angle on the inside to the panels. No more leaks but the mortar is now black with mould and is beginning to crumble.

Any ideas of a mix or cure?

[dennis]

Don't use PVA in the mix, you don't need it and it can grow mould.

You could use a mastic filler to stop the water coming under.

[NT]

any waterproof non-mould sealant. Eg ms polymer sealant, linseed putty if nothing moves, etc. Tiny amounts of sand/cement always fail.

NT