Whether you own a tiled deck or are planning to build one, you’re most likely aware of the moisture-related issues they can experience, including aesthetic problems like efflorescence.

ARDEX has the long-awaited solution, however:  UD 150, an unbonded under tile drainage mat. This first-of-its-kind drainage system eliminates the need for tile jack systems without compromising on the design of a directly adhered tile surface with grouted accents.

The system speeds up drying times and significantly reduces the risk of unsightly efflorescence, common in tiled deck systems without adequate airflow. Efflorescence is a crystalline deposit of salts that appears on tiles, concrete, natural stone and other surfaces. On the surface, efflorescence is unattractive, but if it forms below - called sub-efflorescence or spalling - homeowners may find themselves with an expensive problem on their hands.

ARDEX UD 150 is also suitable for use with a range of substrate options and coverings, including porcelain, ceramic tiles and natural stone. Because the ARDEX UD 150 drainage mat doesn’t need to be bonded to the substrate, it’s an ideal option for those living in regions where councils will not approve the direct fixing of tiles. As Ronald Rose, Technical Services Manager at ARDEX New Zealand explains, the system is ideal for those looking for alternatives.

“Based on the NZBC E2/AS1 document for external decks, many councils have adopted the approach of not allowing tiles or any other coverings to be fully bonded to the waterproof membrane. The waterproofing needs to be accessible, which ARDEX UD 150 allows for.”

The requirement stems from past issues with waterproof decks. In many ways, a deck is similar to a low pitch roof surface. It collects water which, of course, must be drained. There are a few ways to protect the timber substrate of your deck. You can increase the fall, but while you’ll improve drainage, you’ll also end up with a deck that feels quite steep. Some people will add internal and external gutters, but these solutions can quickly become complex.

Then there’s tile jack systems, which offer ease of access and airflow, but come with their own set of issues. Not the least of which is the expensive and thick tile as well as the difficult and time consuming installation process.

Tiles on screw jacks are also less likely to lay flat, even when installed properly. Tile jack systems may also be louder to walk on and can even cheapen the look of a deck even though they may cost more than traditional tiled systems.

That’s where ARDEX UD 150 comes into the picture.

“The membrane offers free movement of water underneath the tiles, essentially eliminating the need for a tile jack system. The system is loose laid and removed without compromising the waterproofing at all.” 

“It’s important for homeowners to be able to access the membrane should an issue arise without compromising the entire surface. Having the ARDEX UD 150 thin under tile mat in place makes this possible. Should a need to access the membrane occur, small areas are able to be removed relatively easily and reinstated.”

The blue polypropylene membrane matting also comes with an ARDEX full system warranty.

To learn more about the family-owned company behind the UD 150 system, be sure to check out ARDEX on ArchiPro. Backed by 60 years experience, ARDEX is an industry leader in the buildings chemicals sector.