TYPE A: BARRIER PROTECTION
These are waterproofing barrier materials which are applied directly to the structure, either external, internal or sandwiched.
More commonly known as ‘tanking’, these applications are normally multi-coat cement-based coatings, epoxy resins or bitumastic type paints.
Type A waterproofing should be applied to well-prepared, clean walls and floor surfaces and can then be covered with on-wall render coats and on floors, sand and cement screeds.
These applications, whether applied externally or internally, are designed to block the passage of water into the building.
There are benefits and downsides to all types of waterproofing. Here are some for Type A waterproofing.
Pros:
- If properly designed and applied, tanking needs no ongoing maintenance.
- These systems can be used on surfaces and wall/ceiling shapes which other types find difficult to be applied to.
Cons:
- Needs much preparation to the substrate prior to application.
- Can move moisture to a previously dry area.
- They are susceptible to building movement and vibration, which may lead to cracking/debonding.
- Take a long time to become dry enough to cover, which may slow down further refurbishments.
- They can lead to a build-up of hydrostatic pressure behind.
- They are generally very messy to prepare and apply being a wet trade.
- Being multicoat, they can take a long time to apply.
- It is very difficult to ensure a true, plum flat, smooth surface finish.
These are some of the things you will need to consider when deciding upon your waterproofing.
Please remember to employ a suitably qualified and experienced CSSW surveyor as part of your design team. Making the wrong choice or taking poor advice could be costly.
Check out the PCA and BSWA websites for specialists in your area.