I applied the Kerdi membrane to the large family room bathroom shower. Getting these showers tiled is a big job that will be done quickly due to having my nephew-in-law visit to do the job. Then we will be able to call for our final inspection this February. If we pass, the remodeling permit will be finalized just about five years from the date of issue.
In 2012, our first year, we had permits for the slab demolition and for the under slab drain plumbing that were already approved. We were able to keep the remodeling permit for so long because we steadily worked on the project being sure to have an inspection every six months.
We have to really thank the inspectors who were so helpful and caring. Arvada’s building department is very busy because there is a building boom in Colorado but the inspectors were never too busy to help us reach our goal. We have a safe, operational, and comfortable home due to their help and intervention.
By the end of the Kerdi application I was getting pretty good at mixing the mortar to the right consistency to apply it to the wall. I always applied half way up the wall first then held the membrane with boards while applying the upper half.
I used a 7 inch rubber putty knife (from Amazon) to smooth out the membrane and drive air pockets to the edges. It worked better than a metal roller.
Rubber putty knife
The membrane overlaps by about 4″ and the tile is applied over the top of the membrane. This is a waterproof layer that prevents moisture from seeping into the DensShield behind the membrane.
Schluter Kerdi applied to rear shower wall
DensShield uses fiberglass instead of paper to manufacture the gypsum boards. That makes it very resistant to water damage. Paperless backer board is required by LEED as a durability factor for bath and shower areas. This requirement is a bit annoying because the shower in the unremodeled bathroom is tile on drywall assuming it is the same as the other bathrooms that we demoed and it has held up fine these thirty years or so. I don’t mind using paperless in the remodeled bathrooms but I would sure like to qualify for LEED without having to remodel another bathroom!
I seemed to have the most trouble this time with accurately cutting the membrane to fit the spots. I had a few mistakes where I had to patch the membrane to fill in where I had measured or cut incorrectly.
Patching the membrane
I patched quite a bit around the shower head wall. Some places had three layers of membrane in order to overlap and to wrap the membrane around the edges.
Shower head wall
The pipe seals were next. I had to take off the end cap on the hand shower pipe to slip on the pipe seal. Then to fit the valve seal over the valve box, I had to cut part of the extended protective rubber to get the membrane seal to fit agains the wall. I was not going to use the valve seal in the master bedroom shower but just caulk around the valve itself, until I remembered the valves have stops (they turn off water at the valve) and the opening has to be big enough to slip in a screwdriver to operate them. The valve seal finally fit after I cut most of the rear protrusion away.
Shower valve seal
Despite all the patching around the shower head wall I was able to finish on the third day of mixing mortar and putting up membrane. I was lucky to take advantage of a warm spell in January, we’ve had a few days of 60 degree sunny weather, but it is supposed to snow tomorrow.