Does spray on rubber membrane products work on older foundations?

Q:

Does spray on rubber membrane products work on older foundations?

A:

Good question. The answer is yes, the product works very well on older foundations, rubberized membrane are engineered to stretch and move, they are able to cover small holes and cracks that would allow water to penetrate any other kind of waterproofing. Rubberized membranes are the only thing that I would use on an older foundation to guarantee a leak free basement. . You must prepare your foundation properly for the installation of a rubberized membrane.

To properly prepare an older foundation there are certain things that you must do.

• You must dig around the entire foundation of the home if you want a 100% guarantee that the house will not leak. If you are only concerned about one side of the home then you must completely expose that side from corner to corner.

• You must dig right down to the footing until it is exposed. The hole must be wide enough that a person can safely work, bend over, twist and turn and the bank must be sloped enough to prevent cave-ins for the workers safety.

• When you have excavated the area check to see if there is a weeper or drainage tile, if there is no weeper install one and if there is an existing one check to see if it is working or is damaged.

• Once the wall is exposed you must remove any old waterproofing material. If the foundation has been tarred then you must use a pressure washer and blast the wall until any loose tar or (if you have enough time) all the tar has been removed.

• With a pressure washer you must remove any leftover dirt, sticks or debris from the walls so that they are clean. You must do this early enough so that the wall is completely dry when they come to spray on the waterproofing.

• Before you proceed with the waterproofing if the foundation is a block foundation then you must drill a hole in the bottom block every couple of feet along the wall. You don’t drill all the way through the block, you only have to drill through one side of the block, this will allow any water to leak out of the block that had penetrated the block in the past.

• Parge any holes that are in the foundation, whether you made them or they are there previously. Any cracks, brakes or seams require filling and smoothing. Any repairs on the foundation should be done now before the waterproofing is installed. Any raised or pointed area's on the foundation wall must be chipped and smoothed out.

• Once the rubber membrane has been sprayed on the foundation, most companies will install a dimple board over top of it. This dimple board is there to protect the membrane from rocks, roots and the membrane when back filling the hole.

• When you back fill the hole you must make sure that the fill you are using is clean, clean means no rocks, stumps, construction debris or anything that can cause damage from puncturing the membrane at a later date.

• You must grade the back fill so that water will run away from the house.

The cost of rubberized membranes is higher then most other kinds of waterproofing but the quality is also much higher. To guarantee a leak free foundation I would only recommend it.

Rob Abbott
Operations Manager
Village Builders Inc.