What is Type A waterproofing?

Type A waterproofing, often called 'Barrier Protection,' involves applying a waterproof material to the internal or external surfaces of the structure. This blocks water ingress physically. Examples include external adhesive membranes applied before backfilling (positive side) or internal multi-coat rendering/tanking slurries (negative side). While effective, Type A relies 100% on the workmanship and substrate preparation; a single defect can lead to failure, which is why we often combine it with other systems.

What is Type B waterproofing?

Type B waterproofing is 'Structurally Integral Protection.' It relies on the design and materials of the structure itself to be water-resistant. This is typically achieved using waterproof concrete (containing hydrophobic admixtures) and waterstops embedded in the construction joints (like hydrophilic strips or metal waterbars). While the concrete itself blocks water, the joints are the weak points, which is why MPS specializes in injection hose systems to seal these joints post-construction if needed.

What is Type C waterproofing?

Type C waterproofing is 'Drained Protection.' Instead of trying to hold back massive hydrostatic pressure physically, it accepts that some water may penetrate the shell but manages it. It uses a Cavity Drain Membrane (an egg-crate shaped plastic sheet) applied to walls and floors. Water runs behind the membrane into a perimeter drainage channel and is directed to a sump pump station, where it is pumped away. This is often considered the safest method for existing basements as it does not rely on perfect structural integrity.

What is 'tanking' a basement?

Tanking is a traditional term for applying a waterproof lining to a basement, effectively turning it into a watertight tank. It usually refers to Type A waterproofing using cementitious slurries or bituminous coatings. Tanking must be able to withstand 'negative hydrostatic pressure'—the water pushing the coating *off* the wall. Because of this, surface preparation (removing paint/plaster to reach the brick/concrete) is absolutely vital for a tanking system to hold.

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Waterproofing Protection Construction

What is a Cavity Drain Membrane?

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What is a Cavity Drain Membrane?

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A Cavity Drain Membrane is a High-Density Polyethylene (HDPE) sheet with a studded profile. It is mechanically fixed to basement walls. The studs create an air gap (cavity) between the wall and the membrane. Any water penetrating the wall runs down this gap into a drainage channel, keeping the internal finish dry. It is a key component of Type C waterproofing and is ideal for damp or salt-contaminated substrates where tanking might fail.

Topics: Waterproofing Protection Construction

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What is a Cavity Drain Membrane?

What is a Cavity Drain Membrane?

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What is a Cavity Drain Membrane?

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