Things to consider before selecting Waterproofing Membranes

Whether it’s a new build or an existing structure, all waterproofing applications should be installed by experienced, licensed waterproofing contractors. Our objective in this article is to make some useful recommendations for the things you may be unaware of on the subject of waterproofing.

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1.         Evaluate the perimeter of your house: Make sure that the ground next to your foundation slopes is away from the foundation, and not towards it. Dirt which is installed as ‘Backfill’ around the foundation, typically at retaining walls, tends to compact over time and settle lower than the surrounding dirt, which is already packed and established. This causes the overall falls to slope towards the house, as opposed to away from it. If necessary/practical, add more dirt up against the foundation to create at least a 150mm per meter slope against the foundation. The top of the dirt should be at least 150mm below the sill plate so that there is no ground contact which can cause certain building materials to rot over time.

2.       Treat your walls with products such as Drylok or Xypex if you have minor leaks: Drylok is waterproofing compound, not a water sealer. It expands as it cures effectively to become part of the wall. Xypex is more akin to applying a waterproof concrete on the surface that bonds with it. Because Xypex relies on the presence of moisture to form its waterproof crystalline structure, if a Xypex application does have small areas of water penetration it would seal itself as it cycles through moisture. You should expect to pay up to 4 times as much for Xypex as you would for the Drylok system. The major limitation with these types of solutions is that groundwater which is underneath the basement floor or at the wall/floor junction will generally be built up with a significant amount of negative pressure, due to the weight of groundwater above it.

3.       Repair defects in walls such as cracks: If you notice a crack in a concrete wall, it may continue right through the wall to the outer surface and is a potential source of water penetration. Any cracks that are not subject to thermal or structural movement can be treated with DRYLOK Fast Plug, which is very effective in sealing cracks in masonry.

4.        Consider installing a sump: Simply put, this is a hole in your basement floor which contains a pump. When the water level in the sump rises too high, a pump kicks in and draws the water out of the sump, discharging it approximately 3m away from the residence.

Things you must know About Lift pits Waterproofing

A Lift pit is a crucial point in construction which has considerable place in the architecture of most multi-storey buildings. Four of the most commonly used waterproofing systems for lift pits include; Self-Adhesive/Torch Applied Bitumen Sheet Membranes, Liquid Applied Polyurethane/Bituminous Membranes, Fibreglass Liners and Cement-Based render systems. Following is a selection of facts which helps Durotech understanding the causes of leaks as well some measures to be taken, by qualified licensed Water proofers and Durotech Accredited Applicators.

1.       The most common cause of leaking lift pits is to do quality of installation. This can point to several different issues including a lack of adequate primer, insufficient detailing and membrane application which does not meet the required thickness. Incorrect membrane selection can also be detrimental to the quality of the overall application.

2.       The installation of Self-Adhesive bitumen sheet membranes can be particularly difficult in poor weather conditions. There is also a tendency not to mechanically terminate these types of membranes, which often leads to poor adhesion quality over time.

3.       Some Cement-Based Membranes can be sensitive to low temperatures, particularly in situations where the temperature can get as low as 5°C.

4.         Fibreglass liners are suitable but the major limitation is that it’s a very labor intensive procedure and can easily fail if concentration is not at a premium during application. The system is quite rigid and limitations also exist with regards to permanent elongation quality.

5.       Bolt Holes, which often run through the walls and the Wall/Floor junctions are the main sources of water ingress, thus it’s important that the lift pits are backfilled correctly for the success of any proposed waterproofing systems.

Buy Waterproofing Membrane | Duroproof™ PPM Polyurethane Membrane

Duroproof™ PPM is a superior performance single component liquid that rapidly form a polyurethane hybrid membrane that is high modulus, flexible, tough and best for exterior use.

Principle Characteristics

·         Easy to use because of single component

·         Combines high distension and flexible strength for excellent toughness

·         Trafficable or tack free overnight cure

·         Good polishing and water resistance

·         Good obstruction to weathering

·         Class III – elongation as per AS/NZ 4858

·         Possibility of high build application

Use Areas

·         Built up concrete roofs and decks

·         Waterproofing of external areas like balconies, podium levels and timber decking etc

·         Light traffic installation

How to prepare surface before installation

Surface must be free of dirt, oily contaminates and old membranes. Grind, sandblast concrete if need. Concrete must be strength of 20MPa and have cured for minimum 28 days. Surfaces must be dry with moisture content below 5%. Fill all holes and cracks with PU sealant. Leak control flanges should be installed around all pipe penetrations. 

Priming

Duromix Hibuild WBE Primer is best primer for general use and PU Primer is best in those conditions where concrete surface needs a primer with good penetration. 

Application

After preparing the surface, apply Duroproof™ PPM by spreader, brush or roller within 48 hours between coats to achieve an optimum intercoat bond. When dry, check for pinholes and rectify. If membrane becomes dirty between coats then clean it with Xylene. Allow 24 hours to dry before covering.

Precautions

Do not apply above 30ºC or below 5ºC ambient temperature. Make ensure before starting the job that rain is not expected between coats.  Protect waterproofing membranes against damage and action of roots.