Water Damaged Retaining Walls Repair
Waterproofing "How To" Sheets- Water Damaged Retaining Walls Repair
Block bricks are commonly used to form retaining walls between properties. Difficulties arise when back filling occurs without tanking the wall and provision for adequate drainage. Water will penetrate the block work, getting behind the render or coating and lifting the surface.
In most of these jobs, there is no opportunity to tank the wall, thus requiring negative tanking techniques. This requires stripping the effected to expose the block work, installing a water stop barrier to the surface, then applying the finished look surface. It should be understood that this will be good solution for the circumstances, but not perfect. It is always best to have the wall properly tanked in the first place.
Products Used
Preparation
Preparation is the key to a good job.
It is important to get back to the block work, removing the render as completely as possible. This may require mechanic chisels. The effected areas of the wall will come away easily, however strongly bonded surfaces will provide more challenges. It is worth being patient to ensure you get a surface in good condition for treatment.
Once all the render is removed to the work area, clean up before starting the next phase.
Application Method
1. With the wall stripped back, identify the wet spot areas which will appear, apply a couple of slurry coats of Contec C1 – crystalline growth compound to the broad zones effected. This product will form a growing crystalline block into the block work.
2. Identify the existing exit drainage holes in the wall, make sure they are clear and add more if necessary.
3. Apply HydrEpoxy 300 coating as a water stop to the entire work area block work. Hydrepoxy is water based two component epoxy polyamide coating which will ‘go off’ relatively quickly, so mix small quantities at a time.
4. Apply the base render coat with suitable bonding agents to the surface of the job.
5. Apply the final coloured render covering.
6. Clean up the work site and touch up any minor blemishes.
Safety Considerations
Safety should always be considered. The main considerations for this type of job is the physical conditions rather than product hazards. Protective eye, breathing and work wear are particularly important. Product safety is highlighted on the packaging, noting that most water based coatings are relatively benign.
Advice
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