Concrete Waterproofing Membrane

Doors to Furnished Basement

Typical Membranes

Typically is a thin layer of material that is placed over the concrete preventing water from entering. These layers are made of, plastic, coated fabric materials, and rubber, or petroleum-based asphalt. This product is available in sheets or as a spray-on. Usually, the layer is 2 to 4 millimeters in thickness.

One of the most important properties of this material is its absorption rate which is approximately 1 to 2% although if the percentage is 4%, it's often considered an acceptable rate of absorption.

The thickness of the material is important and most manufacturers provide a thickness that is uniform in order to provide an application that is even and seamless.

Foundation professionals use this material because it will help to withstand hydrostatic pressure and chemical erosion. Keep in mind, the membrane must offer a low-absorption rate, flexibility, and uniform thickness. This is usually because most foundation companies will use the membrane as the only protection for the foundation.

About Membrane Sheets

These sheets also come in films that mechanically fasten or simply placed next to the concrete Sometimes these membranes are self-adhering, and referred to as “peel and stick” membranes, have an integral layer of adhesives. Before application, the contractor will peel a release liner off the adhesive coating and then stick the membrane on the surface before applying the backfill.

For the record, there are non-adhesive membrane sheets that are PVC and polyurethane rubber sheets that can be removed and repositioned to fit your needs. Contractors can weld the seams and joints of these sheets to reinforce possible weaknesses. For a positive application, the contractor should show caution when preparing the ground. The soil must be compacted and level, sharp stones must be removed, and there should be a layer of sand in place before the backfill can be re-added.

Once you are sure there are no sharp objects that can puncture the membrane, roll it out on top of the concrete forming the shape of the foundation slab while applying it. That said, there could be other issues down the road to consider.

Mold Growing on Basement Wall

Foundation with Basement

There's More Than One Part For Good Foundation Waterproofing

There's no doubt that membrane plays an important part in foundation waterproofing but it's not the only step. There can be several failures that can take place including an unexpected release of bonding from the foundation, failures in curing, inconsistencies in the thickness, and punctures from tree roots or burrowing animals Even an insignificant weakness can allow moisture to enter the concrete creating major problems which over the long-haul will be expensive. Never rely on the membrane alone to protect the foundation. A better choice is crushed Roundstone when combined with a spray-on tar membrane, weeping tiles, a working sump pump, and other measures to keep your basement dry and safe.