This client contacted myself to report on a shower leak in a recently renovated bathroom.
this is not as uncommon as you would inspect, the majority of shower inspected and repaired are around two year old, which is the time it takes for capillary action, wicking and egress to appear in other rooms or below the shower area.
This shower has the usual air pockets in grouts, incorrectly mixed screed ratios and in this case no waterproofing membrane. The membrane should be evident in the waste riser in this particular shower however upon inspection it was pointed out to the owner this was amiss.
the current waterproofing standards can be found here.
Our full shower epoxy regrout and reseal was carried out to prevent the water entering below the tiled surface thus eliminating the nonexistent membrane, this is the same process we use in older bathrooms before membranes were applied.