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7 Biggest Causes of Faulty Waterproofing.

Most people agree, proper waterproofing is the most important element of an entire bathroom renovation.


These are the 7 biggest causes of faulty Waterproofing.

1 – Poor surface preparation and priming.

The waterproofing surface must be free of dirt and dust or the membrane will not bond properly, causing it to peel off. Many tilers skip the priming step altogether to save a few hours and you find it hard to tall if priming has been applied.

2 –  Poor application of waterproofing product. 

Even the slightest spot missed can allow water through. The waterproofing membrane needs to be applied to every millimetre of the area with no render visible. The membrane also needs to extend beyond the wet area.

3 – Only applying 1 coat when 2 coats are needed.

This is probably the biggest shortcut tilers take when it comes to waterproofing. Many tilers swear one coat is enough, when it just isn’t.

4 – Membrane failure.

Low-quality waterproofing can fail. Many tilers opt for the lowest cost waterproofing, especially if you’re a one-time job.

5 – Insufficient drying time between screed an coats.

When tiling a bathroom, a new bed of “screed” (mixture of sand & cement) needs to be laid on the floor. The screed needs to dry before before any primer and waterproofing is applied because the moisture in the screed won’t allow the primer/membrane to bond. Many tilers will waterproof the next day even if the screed hasn’t dried so they don’t lose a day of work.

6 – Poor design and construction.

Another common mistake, not always the tilers fault. “Pooling” or insufficient drainage can occur because  of a poor design such as having a walk-in shower where you shouldn’t or a drain being in a bad location.. Poor drainage can also occur if the tiles are too large for the area, the tiles should have been split or the tiler hasn’t allowed sufficient fall to the drain.

7 – Waterproofing not applied far enough into wet area.

If an effort to save time and money, tilers can stop the waterproofing membrane short of the wet area, allowing water to penetrate through getting behind the membrane.

Just one of these problems could result in your having to renovate you ENTIRE bathroom all over again! .

Before you consider letting anyone waterproof your bathroom ask them these questions:

  • What waterproofing do you use?
  • How many coats are applied?
  • What written warranty is given?
  • Does the manufacturer back-up this warranty?


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