On pre-drywall inspections it isn't often that you see best practices - shower stall waterproofing.
Shower stalls are one area where so many installation mistakes are made, or the wrong products used, you just know it is a problem waiting to happen. When it comes time to have to repair those problems, it is difficult, costly and you are without a shower for a long time!
This shower is a two-person stall beside a large master bath tub.
There will be a glass surround for the shower.
On the walls and around the bath tub, I was told, will be ceramic tile glued onto a barrier of concrete board, a product called Durock.
Durock is an aggregated Portland cement slurry with polymer- coated, glass-fiber mesh which completely encompasses all edges, and the back and front surfaces.
It is an excellent product because it is WATERPROOF.
It doesn't swell, expand or contract, or move. It installs just like drywall.
In the olden days we used a special drywall called green board. It was a drywall product with a little more water RESISTANCE. It was NOT waterproof.
But it was the best we had at the time.
BUT IT IS NO LONGER AN ACCEPTABLE PRODUCT FOR SHOWERS AND BATHROOMS.
But even Durock has seams and gaps that must be sealed. This is where the synthetic rubber membrane comes into play, which you see in the photo. This will be a seat at the end of the shower.
However, the membrane has special installation techniques, which, if followed, will MAKE SURE it is providing a water barrier.
What makes this installation a
> Often I see this membrane installed with drywall screws! Drywall screws are for drywall, and not for any application near water! This installer has used stainless steel, wide-head nails. They are 1" long.
> The membrane is stamped IPC and IRC. Those are where building codes are found and this stuff is code acceptable. The knock offs do not have such a stamp and are OFTEN used.
> The membrane is a SINGLE PIECE and there are no cuts, splits or gaps lower than 4".
> Areas where the Durock will be seamed and there will be stress are double protected with a properly-glued special secondary membrane made for that purpose. It is similar in thickness to bicycle tire inner tubes. It is installed with a special glue.
All in all, this contractor, and supervisor who is watching what is done, knows what he is doing. This is likely to be a dry shower and dry for a long time.
My recommendation: on pre-drywall inspections you have to look for the little things. These little things make HUGE differences in the final outcome of any construction! And it is ALWAYS good to see those little things done well!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560