wrote in message
ups.com...
I've heard of it being used to waterproof cement. What kind of ratio
should I use. I've used it as thin as milk to seal a porus pot and to
seal a hairline crack in a toilet bowl and that has lasted 24 years so
far.

PVA doesn't waterproof cement (I guess you mean mortar or concrete). It's
only a bonding agent. "Waterproof PVA" means it doesn't dissolve in water
as easily as the non-waterproof type, but it's not designed to keep anything
dry. If you want to make a waterproof rendering or screed etc you need a
waterproofing admix, such as FEB or SIKA.