Waterproofing, Coatings and Construction Chemicals
Waterproofing: Should I use a Liquid Coating or a Sheet Membrane?
This article is part of a series about the waterproofing of buildings and constructions. It is relevant to residential and commercial buildings as well as civil engineering projects. It applies to both new build and for repairing an existing building. If you have a commercial project for which you require waterproofing products please contact us.
If you have a roof, wall, floor or foundation etc. that needs waterproofing, then you will need to apply a waterproofing membrane. Waterproofing products fall into two broad categories. These are liquid applied and sheet membranes. This article explains the differences between the two types of product.
Liquid Applied Waterproofing Membranes:
Applied by brush, squeegee or airless spray.
May need more than one coat.
Thickness of membrane sensitive to good application.
Versatile - can be used for most applications.
Sheet Waterproofing Membranes:
Thickness of membrane guaranteed, but overlapping joint must be applied properly.
Torch applied membranes require flame gun for application. Used only for roofs and decking.
Self-adhesive membranes bond to substrate with pre-applied glue. Can be used for most applications.
Liquid Applied Waterproofing Membranes
As the name suggests, these are supplied as a liquid, usually in tins or plastic containers. Liquid waterproof coatings such as EABASSOC RBE, TPU or Spraytec, create a uniform coverage without creases or seams. The thickness and the amount applied can be varied and they are generally easy to apply by brush, squeegee, roller or spraygun. Depending upon what is being waterproofed and the product, more than one coat may be required. When pricing a job, it is important to take the coverage rate into account.
When compared to sheet membranes, liquid applied membranes are more sensitive to good application as regards maintaining a uniform and correct thickness.
Sheet membranes are supplied as semi-flexible rolls which are rolled out onto the surface to be waterproofed. Torch Applied membranes are applied by heating the underside of the membrane with a flame, whilst Self-Adhesive membranes have pre-applied glue that adheres to the substrate. Sheet Membranes give a guaranteed membrane thickness, which is not dependent on the skill of the applicator. However, they do have an overlapping joint which, if not applied properly, can allow water to penetrate.
Torching or Self-Adhesive?
Torch Applied membranes are used for waterproofing flat roofs, inclinded roofs and decking, whereas self-adhesive membranes can also be used for other waterproofing applications such as foundations, basements and floors. Find out more about the differences between torching and self-adhesive membranes. It is also worth noting that applying Torching Membranes does carry a fire risk. Since a flame is required during application, this process should only be undertaken by an experienced contractor. Self-adhesive membranes are bonded using glue that is factory applied to the membrane. The adhesive is covered with backing paper which must be removed before application.
Which Type of Waterproofing Membrane is Best?
Both types of membrane are used for similar applications, for example waterproofing roofs, and they both provide effective waterproofing if correctly applied. The choice of liquid waterproofing or sheet membrane really depends upon personal preference and the skill of the applicator.
Please note that any information or advice on this page is supplied in good faith and that while we make every effort to ensure that it is accurate, helpful and up to date, it is given without commitment or guarantee. We always recommend that trials are carried out prior to undertaking any work or contracts.
Please remember that orders have to be above our minimum size quantity.