Leaking Block Retaining Walls

Leaking Block Retaining Walls

Waterproofing block retaining walls is a necessary part of constructing retaining walls. The retaining structure must have waterproofing designed in the engineering of the structure. This is especially critical when they are subject to groundwater (hydrostatic) pressure. Even when a block retaining wall is just exposed to climatic rainfall the retaining wall’s substructure will experience varying levels of hydrostatic pressure. What if there is a failure in the waterproofing membrane? Then the hydrostatic pressure caused by this water will result in leaking block retaining walls. Eventually leaking block retaining walls will collapse due to structural damage to the masonry.

Waterproofing Retaining Walls

When the waterproofing is on the water side of the retaining wall and known as “traditional waterproofing”.   Designed to stop water penetration of the retaining structure. Normally used in new construction where it is reasonably easy as foundations, footings are still exposed.


Waterproofing retaining walls on the waterside will always give you the best longevity results.

Cementitious Retaining Wall Waterproofing

Cementitious waterproofing products are among the easiest, if not the easiest, waterproofing materials to use. All that is needed is for your block or masonry wall to be clean, efflorescence free, and damp. Clean wall using power water blast. Then remove any efflorescence using  Efflorescence Rid.
The Drizoro Construction Products come to you as a premixed powder. Add the prescribed amount of water. READ instructions on the bag, watch how to video links. Apply using stiff brush or MaxBrush, long-handled broom/brush. Materials readily available from our OnlineWaterproofingShop.

Advantages of the Drizoro Cementitious Coatings and Membrane Systems:-

Any small imperfections in the application of the recommended Drizoro Maxseal or Maxseal Flex will not lead to long-term deterioration and delamination. With many traditional waterproofing membranes pin holes and other small imperfections resulted in total membrane failure. This allows water penetration to penetrate through the block wall retaining.
This means the wall is now leaking. Efflorescence forms on the front of your making the wall look ugly.

Small imperfections in most cases, using Drizoro waterproofing products, will self heal. The adhesion of Drizoro cementitious products works by becoming part of the crystalline matrix of the masonry block wall. The Drizoro membrane coating (correctly applied) will not become delaminated. Failure of other systems will lead to a complete collapse of the wall. We recommend that to prevent damage to the wall when backfilling you use protection board.

Remedial Repairs to Leaking Cement Block Walls

Remedial repairs to the waterproofing down to the footings are impossible as the wall is retaining the soil of a garden burying the original waterproofing. Making rectification much more expensive. The reason this is expensive is that the area, which requires rectification and restoration, may not be able to readily identified.

The membrane failure is below the ground so the determination of exactly where the failure occurs is difficult. The leak on the face wall may not be exactly where the leak originates. A pin hole in the traditional membrane will often track under the initial membrane, via a crack in the masonry surface, or mortar lines.

The next important reason is that to reach any point of failure will require excavation at the very least. This is often not a practical solution or even impossible to reach areas required.

Once the excavation is completed a compatible repair system is required. In some cases, it will be best to remove all of the membrane.
Next is the safety requirements to prevent the earth from collapsing during the repairs.

Waterproofing the Face of Blocks in Retaining Walls

When water is leaking through your block walls causing damage to wall structure it must be stopped. Waterproofing the face wall avoids major works. The retaining block or masonry wall must be clean, efflorescence free, and damp. Clean wall using power water blast. Then remove any efflorescence using  Efflorescence Rid. Then apply MaxSeal to the dampened retaining walls. When the wall is below the water table. (Subject to continuous hydrostatic water pressure) It is essential that all water be drained from the face of the areas to be waterproofed.

Select the MaxSeal product that is most suitable & and apply it to the concrete, block, and masonry surface. Then use Drizoro Maxplug to seal drainage holes and coat them with Drizoro Maxseal Flex.

Cementitious Waterproofing

Cementitious waterproofing increases the longevity of the building structure as it stops water flow through the wall reducing erosion of the concrete. If you think movement of water won’t erode concrete think again. The Grand Canyon was formed by being carved out by the Colorado River in Arizona. It is 277 miles long, up to 18 miles wide and reached depths of over a mile. (we not suggesting you’ll get this depth of erosion in concrete only that it’s is happening) Whilst fresh water is running through masonry blocks chemical destruction of the structural strength of the concrete will continue to occur.

Preventing the flow of water into and through the retaining wall is essential.

This prevents the ongoing degradation of the structural strength and the creation of acidic conditions within the concrete.

  1. Stops the freshwater causing more erosion in the structure
  2. Flowing water also brings a fresh supply of chemicals to attack the structural strength of the structure and
  3. Acid (carbonic acid at the very least) in the water will reduce the highly alkaline nature of the concrete (makes it acid)
  4. The presence of salt will hasten the rusting of reinforcement
  5. The acidic concrete in turn will cause rusting of all steel reinforcement.
  6. Rusting steel expands up to eight times its original size.

Destruction of reinforced concrete or masonry block walls is inevitable.

Sealing Decorative Face Blocks

If you’re using a Decorative face block to avoid efflorescence on a new block wall use Sealtight Clear or Ultra Masonry Block Sealer.
On any block walls which have efflorescence Efflorescence Rid is used to remove any efflorescence and can be sealed against water penetration using Sealtight Clear or Ultra Masonry Block Sealer.

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