It was pointed out to me yesterday, that to date, my blogs are written in a way that assumes some prior technical knowledge about building. Considerable interest about Efflock is coming from home owners, 'Do-It-Yourselfers', or from people who are interested in including Efflock in their building project, but aren't quite sure how to recommend its use or exactly what it does to the tradesmen they are engaging. So here goes....
Firstly, many people may assume that concrete is waterproof:
It makes sense right? You see concrete on bridges, footpaths, driveways and balconies everywhere, so surely water doesn't affect it??
The reality is that even concrete of the highest quality contains small micro cracks that allow water absorption. Water that enters concrete can have decremental affects to it's durability. Water carries pollutants, chloride ions (salt), and it can freeze to cause frost damage. Water travelling through concrete also dissolves and can 'wash out' the alkaline properties within the concrete (known as the pH) to convert the concrete to a more acid state. This phenomenon is often the cause of concrete cancer. (Alkaline protects steel reinforcement, acid causes rust and corrosion of the steel.)
Additives for civil building projects such as bridges, have been around for at least 40 years. Such additives are usually a crystalline technology, where tiny crystals are triggered to grow and fill the tiny pores when in contact with water. These same types of additives only work in structural concrete of high quality with strict controls and cannot be used in smaller scale and lesser quality on-site concrete like that of tile beds which are by nature highly porous. Efflock is new patented technology that works in all types of concrete with the advantage of easy on-site use for all types of applications.
What is a tile bed and where do I find one in a building?
A tile bed is usually a mix of 4 parts sharp clean sand to 1 part Ordinary Portland Cement. This mix is prepared on site by tilers to quite a dry consistency (very little water content) and is spread over a floor to a minimum thickness of normally 30mm to create an accurate substrate for tiling. In wet areas such as bathrooms, falls are created to direct water to drainage outlets.
Tile beds can be found anywhere there are tiles on a floor; bathrooms, laundries, balconies, paths, driveways and sometimes living areas. Most of these applications are subject to water from showers or rain, and an ordinary tile bed without treatment acts as a giant sponge to harbour water. The voids and capillaries within the tile bed also promote a 'wicking' effect for the transportation of water and damp within the layer of the tile bed. A familiar example would be if you allowed one corner of a household sponge to sit in a puddle of water, slowly the whole sponge will suck the water until it is completely saturated. This is what happens with a tile bed, and is one of the reasons that bathroom and balcony leaks are common.
On an exterior balcony tile bed, the same 'wicking' effect occurs. This time though, it can cause unsightly efflorescence because of much higher evaporation occurring between rainy weather. When water travels through the tile bed layer, it dissolves free lime and salt within the concrete. At a point of discharge (grout joints, balcony edges, drainage outlets) this dissolved salty solution evaporates to leave behind calcium carbonate deposits which are the white efflorescence marks.
Adding Efflock to the tile bed mix stops all of these problems.
What about tile grout? The packet says it is hydrophobic, won't that stop water?
Tile grout is a lot less porous. However, if you were to take a sample of cured tile grout and do an absorption test, you will find that it still absorbs water. There are also thermal movements to consider which may allow water penetration to the tile bed underneath. A tiled shower floor may go from less than 10 degrees celsius to above 40 degrees celsius in the time it takes to turn on a tap. Tiles themselves aren't necessarily impervious either.
Efflock shows remarkable results in making these very same off the shelf grouts very hydrophobic. An ordinary sample we tested was completely wet in just 24 hours in a bucket of water. With Efflock, the same grout was bone dry on the inside two weeks later! Grout treated with Efflock resists ingrained mould that is common in standard grout.
I have a waterproof membrane. Surely that will prevent these problems?
Yes, a quality waterproof membrane is still essential. The membrane however is typically located under the tile bed. If there is any kind of compromise in the membrane, it will most likely fail, often causing structural damage to timber or other building elements. The membrane has to work hard under a heavily saturated tile bed that can happily transport water throughout the entire floor. Any tiny lack of detail, a pinhole or damage to the membrane during construction has a saturated body of moisture just waiting for any hint of an exit point. Efflock provides a primary layer of protection with excellent moisture regulation to essentially prevent water getting to the membrane!
Sometimes a secondary membrane over a tile bed is used. This is usually outdoors in a bid to prevent efflorescence. Unfortunately, a secondary membrane can have it's own pitfalls:
- Moisture from the construction process is trapped, sandwiched between two membranes.
- Secondary membranes are often rigid, meaning any shrinkage or movement cracks will allow water entry into the tile bed.
- Can be expensive in labour and materials.
- Extra process resulting in time delays.
- Can actually direct water and associated salts to unwanted areas (i.e. an evaporation or exit point) to cause other problems.