How to build an outdoor waterproof patio using Schluter Systems?

How to build an outdoor waterproof patio using Schluter Systems?

When thinking about a landscaping project, chances are that what comes to mind is a complicated excavation work that drags on for weeks and weeks. By using the right components at each step of the project, you’ll get a beautiful waterproof and weather-resistant terrace with relative ease. Here’s how!

1/ Preparing the surface

The work zone should be protected from sunlight or rain. The temperature of the surface on which you will apply the cement should be between 10°C and 38oC for at least 36 hours to 72 hours prior to this step.


2/ Setting up the wood structure

Three-quarter inch exterior-grade plywood will be fixed to the balcony’s joists, which should be set 16 inches apart. There must be a minimum slope of a quarter-inch per foot directing precipitation away from the structure.


The balcony is then built 6 to 8 inches under the egress points to leave space for a drip cap and to make sure that the waterproof membrane can reach the top of the wall. If the underside of the balcony is exposed to wind or rain, exterior cement sheeting should be installed on the plywood, as per manufacturer’s recommendations.


3/ Installing the roofing membrane

Before installing the roofing membrane, flashings should be set up around the perimeter of the balcony along with a drip cap that will anchor to the walls. Primer #100 is then applied to the surface approximately 30 minutes before applying the membrane, in order to ensure it adheres to the structure.


Spread the roofing membrane on the surface. Make sure it covers the flashings and the drip cap. Designed to provide optimal waterproofing, the roofing membrane must be installed vertically starting from the outer walls, before being spread out horizontally. To this end, we recommend the Resisto’s self-adhesive “High Resistance” roofing membrane made with elastomeric bitumen.

4/ Installing the drainage mat

Made from an impact-resistant waterproof polyethylene film and featuring conical studs, the drainage mat is applied orange side down above the roofing membrane with non-modified tile adhesive, using a ¼ x ¼ trowel.

Drainage mat provides pressure-free drainage and prevents water from seeping into the coating because the top surface is made from a thick polyester layer which allows the air to circulate under the ceramic or natural stone coating, thus ensuring proper ventilation.

5/ Installing the coating

Finally, the ceramic or natural stone coating is laid directly on the drainage mat after applying the non-modified adhesive mortar on the top surface. The tiles must be laid using a double spread method in order to ensure the surface is entirely glued.

Ceramic tiles should be made from high-density porcelain (we recommend European porcelain) or natural stone designed for outdoor use.

Once you can walk on the coating, joint grout can be applied on the connecting joints and the peripheral joints. Schluter has many profiles that are perfect for the Ditra Drain system.


By carefully following these steps, you’ll see that it is easy to build an outdoor patio, as long as you respect the time required for the installation and that you carefully choose the drainage system. For more information, please see our webpage about the innovative products available from Schluter Systems.