Negative Pressure

Is your basement leaking from the outside in? Then it’s time to carry out a negative side waterproofing. Learn how to do it here.

tws negative pressure

How to apply negative pressure membrane to walls & floors

Check with Total Waterproofing Supplies for the correct membrane to use in your area if you are not sure.

This is a generic guide only, giving a basic overview of how to install a membrane.  This information is given in good faith and should NOT be used as a Technical Data Sheet (TDS) or Instruction Sheet.  

When purchasing membranes always download the full TDS sheet and MSDS sheet applicable. All membranes have their own manufacturer’s instruction guide/s,  these must be used when installing membranes.  

You may download this information  from our website or direct from the manufacturer.

retainer wall waterproofing
  • 1. Prepare the area to be waterproofed, remove all render back to brick work, remove all paint back to a clean brick face, remove any efflorescence and treat area with siloxane.
  • 2. Mix the negative pressure membrane with water or with liquid supplied, use a mechanical mixer to ensure an even mix.
  • 3. Wet or moisten the wall area to be waterproofed, then apply a coat of membrane to the wall and extending the membrane onto the floor by 100mm min. (reinforcing cloth can be added to the wet membrane at this stage to the wall and floor junction if required).
  • 4. Allow membrane to dry (this will vary depending on the weather and temperature).
  • 5. Apply a second coat in the same manner as the first coat remembering to wet or moisten the wall again before applicating the membrane to the wall.
  • 6. Allow to dry, please note if the wall was loaded heavily with moisture before the membrane was applied, watery bubbles will appear on the surface of the second coat, this is normal as the membrane is pulling the contained water that is stored in the brick out. This will occur for different lengths of time depending on the amount of stored water in the brick.
  • 7. The membrane may also dry in a patch effect, this too is a result of the stored water in the brick and will evidently dry to a even colour, do not worry as it will have no effect on the membrane performance.