This news article informs you of another common cause of waterproofing failure – Drainage.

DRAINAGE & WATERPROOFING

• Common failures are caused by poor drainage of surface moisture adversely affecting the waterproofing.
• A builder would not install a metal or tiled roof without the minimum specified gradient for surface drainage.
• This however is not the case with waterproofing.
  • It is still a common occurrence that waterproofing membranes are installed on horizontal surfaces without falls for substrate drainage.
  • Single component acrylic membranes were renowned for re-emulsification under saturated conditions in the 1980’s and 1990’s.  (Wet-seal does not have acrylic membranes).
• While products have changed, the construction methods have not.
  • Nearly every part of a building exposed to surface water or conveying water has specified gradients including stormwater pipes, eave gutters, box gutters, sanitary pipes, culvert drains and kerbs.
• Water migrates through grout and builds up over the membrane within the screed.  When there is inadequate fall to the waste outlet, this tends to lead to salt calcification/efflorescence.  This can be avoided by ensuring there is fall to the outlet and good drainage.
• Whilst waterproofing is designed to protect the structure and prevent water ingress into the building there is often little consideration given to the drainage to ensure the waterproofing membrane’s performance.
• The failure of waterproofing is often associated with poor or non-existent drainage particularly at the subsurface level.

For years concrete shower bases have been shaped out & the surface left rough, and in many cases totally unacceptable.

The minimum acceptable requirement is an even wood float finish.  The National Construction Code (NCC) 2016 calls up AS 3740-2010 amendment 2012, page 20 which states “The area shall be clean and dust free, indentations and imperfections shall be kept to a minimum and repaired when necessary”.

The costs involved in carrying out the remedial work can be approximately $150 – $300, or may involve greater costs (e.g. time taken to rectify, etc), when having to get the concreter back to correct the job.

Therefore, it is very important that the concreter provides an acceptable finish ready for waterproofing when they first do the job.

Another way to overcome this issue is to screed with falls, and then waterproof the area.

If a membrane is installed on a rough surface and it fails, the repairs are a major inconvenience for the home owner as the work required to correct the area can include removing shower screens, tiles, mortar bed and the old membrane, as well as rectifying the surface.  In many cases to simply rectify a basic shower, can cost $2500.

If all of the bathroom tiles have to be replaced, then the cost can escalate to between $7500 and can sometimes be in excess of $25,000.

All of this can be avoided by good building practices!

For any other advice of a technical nature, Wet-seal’s highly experienced Technical expert – Robert Rath will be happy to take your call.  Rob can be contacted on 0413 008 303 or via email rrath@wet-seal.ws

Alternatively, please speak with your local Franchisee directly.  Details of your local Franchisee can be found at https://wet-seal.com.au/find-a-franchise/