Single ply systems

FAQ's

1. Should I choose PVC or FPO?

Both membranes have characteristics that provide benefits to the client. Approx 75% of the UK Single Ply market is PVC (FPO is less than 5%) which means that most operatives are more used to welding PVC. FPO/TPO is less forgiving than PVC in its welding window and since operatives are generally used to installing PVC it can lead to poorly welded seams. FPO operatives need to be specifically trained in the FPO membrane to be used. PVC membranes tend to be more generic so are easier to weld. FPO takes longer to weld with a handheld hot air gun, so the labour cost will be higher. Most FPO membranes are lighter in colour (due to thermal expansion issues) whereas PVC is now widely used in dark grey colour in the UK. You cannot get decorative profiles with FPO due to thermal expansion issues. FPO has no plasticisers in it as it is a naturally flexible membrane; so, if buried therefore removing UV degradation, an FPO membrane will have an exceptional life expectancy.

2. Whats the difference between FPO (Thermoplan) & PVC (Thermofol)?

PVC and FPO membranes are both heat welded at the seams giving superior protection against leaks as the two sheets are fused together forming a complete and durable roofing membrane system.
FPO membrane usually needs lap preparation to remove surface static which can otherwise interfere with the weld.
 
PVC (polyvinyl chloride) and FPO (Flexible polyolefin) share many common characteristics, neither can claim an overall superiority over the other, however particular characteristics of each of these two polymers can be exploited by the specifier to enhance the specification of their single ply roofing system.
 
3. Fire Resistance

The manufacturing formulation of PVC roof membranes gives them good inherent properties (ie: Chlorine) in relation to fire performance, although additives are required to ensure system passes for TS 1187 BRoof (t4).
FPO membranes also require additives to enhance their fire performance.
Bauder have completed numerous Single Ply system fire performance tests to BRoof(t4) at both zero and 45 degrees; a selection of these is detailed in the BBA certificates; for a full list contact the Single Ply Product Manager
 
4. FM (Factory Mutual)

FM approvals is the independent testing/approval arm of international insurance carrier, FM Global. FM approvals uses scientific research and testing to make sure products conform to the highest standards for safety and property loss prevention. Products that pass get the “FM APPROVED” mark.  Bauder have 28 different Single Ply assemblies that have achieved an FM approval. These approvals are for mechanically fastened and ballasted assemblies.
For more details please contact the Single Ply Product Manager.
 
5. Can I have a green roof over Single Ply Membranes?

Absolutely. All 1.5mm & thicker Thermofol & Thermoplan membranes have FLL root barrier certification ensuring they are suitable for green roofs.
 
6. Should it be a mech fixed or adhered system?

There are too many considerations to provide a comprehensive ‘best solution’ to this question.
If the substrate is metal or plywood then mechanically fastening may be more suitable than if it’s a concrete deck. However, fasteners will be seen through a metal or plywood deck so if it’s an exposed underside of deck this may not be acceptable. As a rule, mechanically fastened systems with a polyethylene AVCL will be cheaper than a bituminous AVCL and a fleece-backed membrane with adhesives. However, a bituminous AVCL (2.5mm plus thickness) will provide the building with a temporary waterproofing layer which may be beneficial to the project’s installation programme.
Aesthetics are an important consideration when specifying single ply membranes. Mechanically fastened systems can be more susceptible to thermal movement than adhered membranes; also mechanically fastened membranes may ‘flutter’ more in higher windloads which may not provide the client with the desired effect.
In coastal locations or high buildings where windloads are higher than normal, it may be that an adhered system is not suitable, and a mechanically fastened solution is the only answer. A project specific windload calculation will determine whether adhered is possible.
In some instances, a hybrid build up is a good solution. Mechanically fastening insulation through a polyethylene AVCL keeps costs lower than employing a bituminous AVCL and then adhering a fleece-backed membrane will enhance the aesthetics.
Acoustics and Air Leakage may be additional considerations; often a fully adhered solution will be more suitable in these situations.
 
7. What is the RAL number of this Bauder Single Ply membrane?

• Thermofol Light Grey 7035
• Thermofol Blue Grey 7031
• Thermofol Anthracite 7016
• Thermofol Walkway 7012
• Thermoplan Pearl White 1013
• Thermoplan Silver Grey 7001
• Thermoplan Walkway 7016

 
8. What is SPRA?

SPRA (Single Ply Roofing Association) is the trade association representing the UK’s single ply roofing industry. Their mission is to achieve growth and sustainability in all sectors of the single ply roofing industry by raising the awareness of single ply technology, its value and ensuring manufacturing and installation standards remain high. SPRA is an increasingly influential voice in the roofing sector and is working in close co-operation with our sister trade associations to raise the overall profile of the UK roofing industry.
SPRA members are actively involved in the monitoring, development and reporting of cutting-edge technologies to improve single ply products, installations and aftercare. 
Bauder are a Manufacturer member of SPRA and Nigel Blacklock is chair of the Technical Committee and a member of the SPRA Council.
The SPRA Design Guide is an excellent reference document. You can download a copy at www.spra.co.uk
 
9. How do I protect the roof from following trades?

Following trades on a finished Bauder roof should always make provision for protection of the waterproofing. The most common protection being in the form of FSM600 Protection layer followed by a layer of plywood. This should provide adequate protection for the waterproofing whilst following trades carry out their remaining works. Ensure that any items of plant/equipment that may have been introduced to the roof are sited on suitable isolated slabs, with additional surface protection beneath, and that any fixings that may have been used to secure them, do not penetrate the waterproofing. Once works are finished, clear all debris from the roof surface, rainwater outlets, chutes, gutters etc. Debris must be removed from the roof and not simply flushed down rainwater pipes.  Any waterproofing damage caused after completion of the original installation may invalidate the guarantee.
 
10. Stainless Steel Vertical Outlets (spigot length 400mm)
 

• DN70 (to suit 75mm-97mm rainwater pipe) –      2.98l/s flowrate
• DN100 (to suit 110mm-128mm rainwater pipe) – 3.94l/s flowrate      @35mm head of water
• DN150 (to suit 160mm-178mm rainwater pipe) – 6.76l/s flowrate          with leafguard

High performance stainless steel outlets with factory installed PVC/FPO membrane flange. Supplied with an O-ring and a wire ball leaf grate.
 
If an extension pipe is necessary for these stainless steel outlets then Fixfast can provide these from stock.
  
11. Rigid PVC/FPO Balcony/Parapet Outlets (spigot length 480mm) 

• DN100  - 1l/s flowrate         -         @35mm head of water

The rigid PVC and FPO parapet outlets enable the membrane to be welded to the flange plate. UV stable throughout. The unbacked membrane should be heat welded upto the aperture to ensure colour consistency on the roof.