Seeping through the cracks – bathroom waterproofing

Over the years of renovating bathrooms I have seen all sorts of waterproofing problems. When the old bathroom is removed many of the houses have no waterproofing at all or some have an old fibreglass patch job which has failed. The worst bathroom I have seen was when we removed a bathroom on the bottom floor, of a two story home, to find half a metre or approximately two feet of the load bearing timbers were just black compost. Needless to say the bathroom that to have a lot of construction work done before new waterproofing was put in. If you renovate a old home you may find that only the shower was waterproofed (maybe), but today’s waterproofing standard means the whole room is waterproofed.

Waterproofing a bathroom – the facts

• Insurance companies say that 90% of bathroom claims relate to waterproofing failing.
• Waterproofing is black and white or it either is fully waterproofed or it is not at all.
• Their is no trade qualification for waterproofing just a four day course – so beware if you use a so called ’waterproofing tradesman’.
• If a bathroom is not waterproof properly the results are large financial costs  – removing tiles, fitting, etc. to do it again.
• The cheapest waterproofing may not perform well over the long term.

Waterproofing your bathroom is an easy job that can be done by anybody with a paint brush, however that doesn’t mean it is waterproofed. While it is easy to apply, great care must be taken to cover all areas with an emphasis on quality.

How to waterproof your bathroom

• Waterproof the whole room -the whole floor,  up the wall 50-100mm and 300mm higher than the shower rose in the shower recess.
• Waterproofing the whole room is called ‘tanking’ and effectively directs all water to a drainage outlet.
• Add an aluminium angle strip to the doorway – glue down and then waterproof over so no water can escape out of that doorway.
• Make sure the floors and walls are correct and sound before waterproofing begins.
• Always use a waterproofing primier  – this binds to the floor and wall material and stops any dusting (dry unstable dust) to create a good base.
• Brush your waterproofing one way (left to right) for the first coat and the opposite way for the second coat – this ensures good coverage takes care of pin prick holes.
• Always follow the manufactures instructions as this may vary between brands.
• Never add water to the waterproofing mix.

Types of Waterproof

• Latex – Latex rubber based – these air dry, but in winter can take up four days to dry.
• Cement based two part – Cement polymer – add dry and wet parts and mix  -  2 hours to re-coat – 6 hours to fully set.
• Bitumen based – Has a better drying time then Latex but is not as flexible.

Most modern types of waterproofing are good because they have been manufactured to a building industry standard. This makes them good to use as long as they can be used for bathrooms. However I have found the two part waterproof great because it sets chemically and I don’t have to wait for long periods before moving on with the next part of the renovation. Latex based are good however they can take a long time to dry in cooler climates and you may need a heat source in the room so they completely dry. Also the Latex is not as durable to foot traffic as the cement based and thus more care must be taken so it is not damaged before it is covered with cement or tiles. There are many brands and prices and I don’t wish to recommend a particular one as their are many that would do the same job. So check with your waterproofing supplier or hardware for more information. For best result and if you can buy from a waterproofing supplier as they know their products and specialise in them everyday.

Tagged as: bathrooms, Waterproofing