Waterproofing

The Importance of Green Roofs in Sustainable Buildings

The Evolution of Waterproofing Systems Made of PVC Membranes

Introduction

During the last Century, architects have tried to diminish the consumption of energy by introducing the concept of Green Roof as one of the most important characteristic in Sustainable Buildings. The success of this kind of roofs depends on the waterproofing system. PVC Membranes are the main component of waterproofing systems suggested for waterproof Green Roofs. It is due to their efficiency and durability. A LEED Certificate distinguishes Sustainable Buildings. In order to obtain a LEED Certification it is desirable to include a Green Roof as a characteristic of the building. A PVC Membrane Waterproofing System was chosen to insulate the roof pertaining to the case of study described below.

Case of Study

CA Group Corporative Building is a sustainable building which has a Green Roof as one of the conditions to obtain a LEED Certification. Owners decided to cover 120m2 of the total area of the roof with a Green Roof. In this case a PVC Membrane Waterproofing System was chosen. The most important characteristic for waterproofing materials is elongation, PVC membranes have an elongation of 300%. PVC membranes may be applied by using mainly two methods which are:

• Mechanically Fastened System
• Fully Adhered Systems

Fully Adhered Systems for Sarnafil®/Sikaplan® PVC Membranes

Fully adhered systems give the roof a superior aesthetic appearance. They do not penetrate into the roof slab taking care of the substrate where the PVC membrane will be bonded. In the following list describes the main steps required to install PVC Membranes by Fully Adhered System.

1. Ensure to have a clean substrate free from any greasy substance and dust
2. Extend the sheet of membrane over the slab and then fold in half
3. Apply the double contact adhesive Sarnacol® with a roll all over the substrate and the membrane
4. After 10 minutes extend the membrane over the substrate which was previously covered with the adhesive.
5. Repeat the same procedure with the next sheet of membrane. Previously overlap 10 cm over the first sheet of membrane.
6. Cover the whole surface and weld the seams layer. Use a hot air welder at 300/600°C

Conclusion

• This system can be applied on new and refurbishment roofs.
• Green Roofs waterproofed with a PVC membrane applied fully adhered have a particular root resistance. It is due to the PVC membrane´s technical characteristics and also to its hot air welded seams.

References

• PVC Membranes - Manual Of Aplication Sika