Roofing systems & fastening solutions
From single ply to a hybrid system
This article describes the most common mechanically fastened flat-roof systems, together with an overview of the efficient and durable Guardian fastening solutions for each system.
The European flat roof industry represents an annual volume of around 450 million m2. The ratio between synthetic and bitumen membranes varies from one country to the next. In many European countries, the market share of bitumen roof membranes still represents 60% or more of the total number of square meters. However, in most countries, a clear trend is visible towards a rising market share of synthetic roof membranes. Particularly involving large projects, such as distribution centres and warehouses, where synthetic materials are increasingly applied. The divers Guardian product range offers solutions for every roof build-up.
Mechanically attached single ply - synthetic roof membrane systems
Material
- Reinforced PVC, thickness 1,2-2,0 mm
- Reinforced TPO/FPO, thickness 1,2-2,0 mm
- EPDM, thickness 1.1-2.1 mm
Common roof membrane widths:
1,0/1,5/1,6/2,0/2,1 meters
Mechanically attached single ply roof systems are applied on various building types, such as shopping centres, logistic centres, schools, hospitals, etc. ‘Warm roof’ constructions with an assembly made up of a structural roof deck, vapour barrier, insulation material, and covered with a synthetic roof membrane are commonly used in the roofing market.
The single ply reinforced synthetic roof membranes are applied with an overlap of approx 100/120 mm. The synthetic membranes are welded with hot air, with a 40-mm wide welding seam in the overlap. The remainder of the overlap, 60/80 mm, is used for the mechanical fastening of tubes that fasten the roof build-up to the roof structure. The producers of synthetic roof membranes manufacture their membranes in different widths.
Wide rolls of 2 meters or more are used for roof zones with the lowest wind load. In perimeter and corner zones, smaller membrane widths are used to resist the higher wind loads in these zones better. The number of fasteners per m2 is determined by the actual wind load of the roof according to the European wind load standard EN 1991-1-4.
Induction welding technology
An alternative to overlap fastening is the method with which the roof membrane is bonded to specially developed pressure plates using induction welding technology. In this case, the overlap width will be 60 mm. The pressure plates are not applied in the overlap but on the insulation material according to a predetermined pattern (field fastening) depending on the wind load.
The membrane is then rolled out across the roof. Each plate is bonded to the bottom of the membrane using induction welding equipment (GuardianWeld), without perforating the roof membrane.
Guardian fastening solutions for synthetic roof membrane systems
Guardian offers a wide range of pressure plates and plastic tubes for the safe fastening of synthetic membrane systems, both on soft and hard substrates (insulation). The standard range of Guardian overlap fasteners has design load values of 500-700 N/fastener, depending on the type of membrane. The high-performance range from the Guardian range achieves design load values as high as 700-900 N/fastener. The design load values for each membrane - plate/tube combination has been determined on the basis of full-scale wind uplift tests according to EN 16002 testing method.
| Guardian standard overlap fasteners for synthetic roof membrane systems |
|---|
| Design load values of 500-700 N/fastener |
| SP 40 membrane plate, flat and recessed design |
| SP 8240 membrane plate, flat and recessed design |
| R 48/R 50 membrane tube, round |
| SP 50 membrane plate, flat and recessed design |
| SPA 8240 membrane plate, recessed design, for use with automatic setting tool |
| Guardian high-performance overlap fasteners for synthetic roof membrane systems |
|---|
| Design load values of 700-900 N/fastener |
| SPBA 8240 toothed membrane plate, for use with automatic setting tool |
| RB 48/RB 50 barbed tube; round |
| Induction technology |
|---|
| GuardianWeld induction system for fastening of PVC, TPO/FPO and EPDM roof membrane systems |
Mechanically attached one layer - bitumen roof membrane systems
Material
- Reinforced SBS, thickness 3,5–5,5 mm
- Reinforced APP, thickness 3,5–5,0 mm
- Common membrane width: 1,0 m
Mechanically attached one layer bitumen roof systems are used on residential buildings as well as on commercial and non-commercial buildings. Cold-roof systems with a wooden roofing floor, but mostly warm-roof structures made up of a roofing floor, (vapour barrier) insulation and topped with a one layer bituminous roof membrane, are often used in the Northern European market.
An important feature of modern one layer bituminous membranes is that these are manufactured with a reinforcement of high-quality polyester. These roof membranes are normally installed with an overlap of approx 100 mm. The complete overlap is welded using a torch or hot air. The mechanical fasteners that are used to fix the roof build-up to the roof structure are integrated in the welded overlap. The most common membrane width is 1,0 m. The required number of fasteners depends on the wind load of the roof according to the European wind load standard EN 1991-1-4
Guardian fastening solutions for one layer bitumen based roof systems
Guardian offers a wide range of pressure plates, plastic tubes, and fasteners for the safe fastening of one layer bituminous roof membrane systems, both on soft and hard substrates (insulation). The standard range of Guardian overlap fasteners has design load values of 450-650 N/fastener, depending on the membrane type.
The high-performance range of the Guardian assortment achieves design values of 650-850 N/fastener. The design load for each membrane-plate/tube combination is determined on the basis of full scale wind uplift tests according to EN 16002 testing method.
| Guardian standard overlap fasteners for one layer bituminous systems |
|---|
| Design values of 450-650 N/fastener |
| SP 40 pressure plate; round, bottom side flat or recessed |
| SP 50 pressure plate; round, bottom side flat or recessed |
| SP 8240 pressure plate; rectangular, bottom side flat or recessed |
| SPA 8240 pressure plate; rectangular, bottom side flat or recessed, for use with automatic setting tool |
| R 48/R 50 plastic tube; round |
Mechanically attached two layer - bitumen roof membrane systems
Materiaal
- Basic layer: Polyester-reinforced SBS or
APP, thickness 2,5-3,0 mm (2500-3500 g/m2) - Top layer: Glass/polyester-reinforced SBS or
APP, thickness 3,5-5,0 mm (4000-5000 g/m2) - Common membrane width: 1,0 m
Mechanically attached bitumen two layer roof systems are applied on residential buildings as well as commercial and non-commercial buildings. Cold-roof systems with a wooden roofing floor, but mostly warm-roof structures with an assembly of roof structure-vapour barrier-insulation and the multi-layer bituminous roof membrane system above that, are very common in the market.
The European roof membrane market has a wide variety of multi-layer bituminous systems. A distinctive feature of these systems is their base layer, which often has an improved polyester reinforcement compared to the traditional torch-on and bonded systems. This gives the membrane the required strength when tubes and pressure plates are used to fasten the build-up of the membrane system to the roof structure.
There are 2 methods to mechanically fasten multi-layer bitumen roof systems
Method 1 Field fastening
The pressure plates or tubes are fastened in the base layer according to a predetermined pattern, independent of the overlaps of the base layer (field fastening). This is done in symmetrical patterns or in patterns adapted to the specific roof structure. When the base layer has been applied/installed, the top layer is then torched, or bonded with hot bitumen on the base layer.
Method 2 Overlap fastening
This method is widely used in Scandinavian countries. The plates or tubes are fastened in the 10-cm wide overlap of the base layer. The overlap is then torched in the same way as single-layer bituminous systems. The top layer is then burnt or bonded with hot bitumen on the base layer.
Guardian fastening solutions for multi-layer bitumen based roof systems
Guardian offers a wide range of pressure plates and plastic tubes for the safe fastening of multi-layer bituminous roof membrane systems, both on soft and hard substrates (insulation). The standard range of Guardian overlap fasteners has design values of 450-650 N/fastener, depending on the membrane type. The high-performance range of Guardian pressure plates and tubes achieves design values as high as 650-850 N/fastener. The design load for each membrane/plate-tube combination is determined on the basis of full-scale wind uplift tests according to the EN 16002 testing method.
| Guardian fasteners for multi-layer bituminous roof membrane systems |
|---|
| Design values of 700-900 N/fastener |
| Method 1 |
| SP 70 membrane plate, flat and recessed design |
| R 75 standard tube |
| Method 2 |
| SP-40 |
| SP 50 pressure plate, flat and recessed design |
| R 48/R 50 standard tube |
Torch on / Pour & Roll single or two layer - bitumen roof membrane systems
Material
- Base layer: glass-reinforced SBS or APP thickness 2,5-3,5 mm/m2)
- Glass/polyester-reinforced SBS or APP thickness 2,5–3,5 mm/m2)
- Top layer: glass/polyester-reinforced SBS or APP thickness 3,5-5,0 mm (4000-5000 g/m2)
- Usual roof membrane width: 1,0 m
Torch on or Pour & Roll single or two layer - bitumen roof membrane systems are very common roof systems. The roof membranes are bonded onto the substrate. These systems are directly bonded onto the roof structure, for example on concrete, or on mechanically fastened insulation boards or underlayers (suitable for bonding).
The insulation boards are fastened to the roof structure by means of pressure plates or tubes. The required fastening pattern (number of fasteners per m2) is determined by the wind load of the roof according to the European wind load standard EN 1994-1-4.
| Guardian fasteners for insulation boards and underlayers |
|---|
| SP 70 pressure plate; round, bottom side flat and recessed (thickness 0.70 mm) |
| R 75 tube |
Adhered single-ply synthetic roof membrane systems
Material
- PVC, TPO or EPDM, with or without lining on the underside
- Common roof membrane width: 1,0 m, 1,5 m, 2,0 m
Adhered single-ply synthetic roof membrane systems are popular in various European countries. Depending on the wind load and roofing system, the roof membrane is completely or partially glued onto the substrate. The systems are usually glued onto mechanically fastened insulation boards or underlayers, boards (suitable for gluing).
The insulation boards or underlayers are installed to the roof structure by means of pressure plates or tubes. The required fastening pattern (number of fasteners per m2) is determined by the wind load of the roof according to the European wind load standard EN 1994-1-4.
| Guardian fasteners for insulation boards |
|---|
| SP 70 pressure plate; round, bottom side flat and recessed (thickness 0,70 mm) |
| R 75 tube |
Insulation boards glued to roof structure
Insulation boards can be glued to the roof structure in various patterns depending on the wind load of the roof. Buildings with high humidity and high temperatures will benefit from insulation boards that are glued on the inside because this does not require fasteners that could penetrate the vapour barrier. For all other building types and roof structures, mechanical fastening of insulation boards using Guardian tubes and pressure plates provides a clear advantage compared to glued boards.
Advantages of mechanical fastening of insulation boards:
- Saves application time, especially when the insulation is made up of multiple layers
- Significant savings in application and material costs
- Application at low temperatures possible
- The substrate does not have to be completely dry
- It is possible to perform highly accurate wind load calculations
- Limited thermal bridges with plastic Guardian tubes
Hybride roofing systems
When mechanically fastening flat roofs it often happens that narrower membranes or centerline fixings are used, especially in the corners and perimeters.
By using the GuardianWeld™ induction system in these zones, a single membrane width can be used for the entire roof. Fasteners that are normally needed to accommodate for the narrower membrane width or centerline fixings are completely replaced by the GuardianWeld™ induction fasteners.
Suitable for pvc, tpo and epdm (European) membranes.
Advantages at a glance:
- Only a single membrane width needed per project
- Corner and perimeter waterproof faster compared to traditional mechanical fastening
- Combination of traditional and innovative system
- Reducing the total amount of fasteners
- Less and smaller overlaps needed for the membrane
| System | Regular fastener | GuardianWeld™ induction fastener | Overlap meters | Membrane surface |
|---|---|---|---|---|
| Traditional mechanically fastened | 4484 pcs | - | 1390 m | 1070 m² |
| Hybrid system | 2064 pcs | 1032 pcs | 640 m | 980 m² |
Project example
Building in the center of the Netherlands
- Height: 12,5m
- Surface area: 7000m2
- Corner and perimeter: 900m2
Example corner and perimeter with narrow membrane width
Example GuardianWeld™ hybrid system with wide membrane width