Tile Shower Pan – The Top Mud Layer

The tile shower pan built the traditional way is built from the bottom up in layers. The heart of the pan is the vinyl membrane that really stops any water that makes it past the shower floor. You do realize that shower floors naturally leak??? The pan is built to catch that water. After the liner membrane is in place, a second layer of mortar goes over the liner and it’s the base for the tile. Here’s how it goes on.

The second mortar layer of the pan is constructed of what’s called deck mud. It’s a simple mix of portland cement, sand and water. That’s all. It’s put on and then formed using a flat trowel and pieces of boards. The mortar is sloped at about 1/4 inch per foot to make sure the water moves right to the drain.

In order to have enough mass to make for a strong layer, the minimum thickness of the mortar at the drain should be 1 1/4 inches. Otherwise it’s possible the mortar could crumble over time. But with the proper thickness the mortar layer is plenty strong without any special additives or ingredients. All you need is the deck mud recipe with the water kept at a minimum so the finished mix is just moist. A soupy mortar mix is not acceptable since it will shrink too much as it dries.

The second mortar layer, the top layer, of the tile shower pan is the base for the ceramic tile. It’s made of simple material and shaped with simple tools. The real work of building the leak-proof shower has been done by the time this layer is finished.

By master