Why Use PVC Single Ply Membranes?
Simply put they’re a single layer of waterproofing membrane normally made from various combinations of manmade synthetic materials.
The first single ply membranes were created over 70 years ago in Germany and have been successfully used across the globe since then, collectively covering many millions of square metres of flat and shaped roofs.
How Do They Compare With More Traditional Flat Roofing Materials?
Here in the UK most of our flat roofs are covered with multi layered mineral felts or asphalt. The main advantage of these coverings is that they are generally very cheap and over the years manufacturers have moved to create a DIY type of product available to the general public and small jobbing builders.
The Challenge With These Types Of Products Is Basically Twofold:
However Be Warned As Not All Single Ply Membranes and Manufacturers are Created Equal
As with most things in life there is good, bad and indifferent and the single ply membrane industry is no different.
As a general rule of thumb make sure you only consider membranes that have been independently assessed and tested by the BBA and have the certification to back up any claims of performance, assuming you’re looking for a long lasting system.
Different Types Of Installation Systems
Mechanically Fastened V’s Fully Bonded: Both systems have advantages and disadvantages. As a general rule of thumb if your substrate deck is timber you would use the mechanically fastened systems and if it’s concrete or say wood wool slabs you would normally use a fully bonded system.
Please be aware though the fully bonded systems should not be installed if the temperature is less than 5 degrees.
Heat Welded Joins or Glued Joins: Without question a proper heat welded join is far superior to the various glued and taped systems out there. This is because no-one has any control over the moisture levels and temperature which affect all adhesives, where as welds created using a heat gun are more consistent and not affected by the weather.
You May Want To Check the Guarantee & Small Print
Over the last 23 years we’ve come across all sorts of guarantee claims, even some running up to 50 years! However in our experience a serious guarantee which is normally between 15 and 20 years long should have the following:
The Membrane Is Only Half Of the Story!
Picking the right membrane is only part of the solution, making sure you secure the services of a contractor team that have both the experience and are accredited by the membrane manufacturer which is key to a long term solution.
You also need to make sure you take references and request sight of a current public liability insurance certificate in excess of £5 million.
Also bear in mind that many contractors only have experience in new build projects which tend to be much simpler with fewer challenges. If your project is a refurbishment then you need to find a contractor that has significant experience with the most challenging side of installing.
County Flat Roofing of Weston-Super-Mare, Somerset is your registered Sarnafil, Alwitra and Cefil single ply flat roof installer.