When it comes to roofing, along with any structure project, there can be a lot of jargon to cut through to understand everything you need about a project. Even if you’re not doing the installation yourself, it is important to familiarize with terms and techniques, so you know what the professionals are doing, and why they are doing it. One of the common bits of confusion in the roofing world is with lamination and saturation with regards to waterproofing.
Waterproofing your roof happens at the membrane. This membrane can be laminated or saturated. A membrane usually has 3 layers. A base layer, some type of matting or scrim in the middle, and then a top layer. It is all laminated into one, with the top layer being the primary waterproofing level. If the top layer is rated at 15 mls of waterproofing, and the entire product is 45 mils, and you can expect lose 1-2 mils every year, then after 10 years you will have worn that layer down halfway. At that point, your roof is close to the point of failure. With laminated sheets, if something punctures through that top layer, then the whole section of roof is potentially compromised.
The saturation technique creates a waterproofing effect throughout the whole membrane, and not just one layer. First, there is liquid base waterproofing layer. Polyester matting is then installed on top of that liquid layer. By installing the scrim while the base is wet, it saturates the middle layer. Then, there are two layers of liquid waterproofing placed on top of the scrim, to saturate it from the top as well. This reinforces the waterproof protection, and makes the entire membrane stronger throughout. If something punctures the top layer, then there are still other layers that help prevent water from coming in. This system can be installed on top of an old roof, so there is no need to demolish what is already there. Plus, a saturated membrane does not wear down as fast as a laminated one.
Hopefully this guide has clarified the differences between laminated and saturated roofing membranes. Now if a roofing professional talks to you about your options, you’ll have a better understanding of the differences.