What to look for when building/refurbishing a flat roof.

What to look for when building/refurbishing a flat roof.

Flat roofs are now back in demand and are favoured amongst building owners and architects. With extended life-spans, ease of maintenance, and proven resistance to the climate fluctuations of the British weather! Flat roofs have a high performance and cost effectiveness that when installed and maintained correctly, a flat roof will provide a long service life.

But how do you build a good flat roof?


The roof is the base upon which the entire flat roof relies upon. It must be designed to provide sufficient support for all loads to which it will be exposed, and the method of attachment to it must be appropriate.
Vapour Control layer – Warm roof construction:
Vapour control layers are considered essential under insulation in warm roof construction, more commonly known as a VCL helps to reduce the risk of condensation forming in the flat roof structure.

Insulation – Warm Roof Construction

Insulation is essential on all flat roofs to offices, homes, extensions etc. preventing heat loss through the flat roof. Insulation is rarely used on outbuildings, garages and other buildings which are not heated and will not offer any economic benefits.

U Value:

Building Regulations dictate that certain U Values must be achieved for both new and refurbished flat roofs. The overall roof must meet the requirements of the Building Regulations with regards to the “U” value. Endon Roofing will survey the roof and offer options to provide a flat roof build up to meet with current building regulations.

Flat Roof falls:

A flat roof needs to be able to shed surface water to the gutters. The required falls may be formed by the slope of the joists, tapered firrings installed under a suitable roof deck or a tapered insulation laid to provide falls.

Single Ply Membrane:

The right choice of membrane is critical. Endon Roofing source membranes from accredited, quality manufacturers to provide a high-quality waterproofing solution. Endon Roofing install a high-quality single ply membrane with a life expectancy of at least 30 years.


Alwitra is widely recognised as a leading quality brand in both the commercial and domestic flat roofing industry.

All products are sound and sustainable, with an emphasis on the environment, and roof systems that are ecologically beneficial.

Products supplied include single ply roofing membranes and accessories, green roof systems and accessories, and roof edge safety railing systems. Alwitra single ply membranes offer excellent waterproofing properties and can be covered by a choice of warranties for up to 20 years. The range includes the world’s first single ply membrane to incorporate flexible thin film photovoltaic cells.

The Alwitra flat roofing system has at its core three main single-ply waterproofing membranes, and we would be delighted to advise on product suitability in line with your requirements and preferences.

Evalon®-V is a vinyl-ethylene-terpolymer (VET), comprising polyvinyl-chloride (PVC) and ethylene-vinyl-acetate (EVA), which results in an extremely stable product, free from potentially harmful plasticisers.


Alkorplan single ply membrane has been used worldwide for almost 40 years waterproofing all building types from individual dwellings to complete commercial centres, for both new build and refurbishment projects.

Alkorplan has a wide range of colours, is quick and easy to install without any naked flames used during installation. It is also extremely durable, with a life expectancy of over 35 years which is certified by the BBA. For commercial customers, insurance backed warranties can also be provided on flat roof installations.


Flag Soprema membrane is lightweight, nontoxic, resistant to root growth with a life expectancy of 30 years and BBA Approved. Flag Soprema high performance 3 layer torch on felt system is usually made up as a warm roof construction which includes Primer, Vapour Barrier, Insulation, Intermediate layer and Mineral Capsheet.

With manufacturers warranties available on all flat roofs ranging from 10 – 20 years.

If your commercial roofing project is specced for a single ply membrane or high performance felt system, contact Endon Roofing with full details where we can provide a full detailed quotation for your building requirements.

Benefits of Flag Soprema include:

  • Excellent and flexibility
  • Dimensional stability and high weather and UV rays resistance
  • Non-toxic
  • Resistant to a wide range of chemicals
  • Compatibility with most insulation panels, including expanded/extruded polystyrene and oxidised bitumen
  • High resistance to puncturing, roots and micro-organisms
  • Adaptable to structural movements
  • Environment and user friendly
  • Life expectancy in excess of 25 years The British Board of Agreement (BBA) Certificate No. 00/3750 states, durability/life expectancy for  FLAGON TPO products (FLAGON EP/PR type) to be in excess of 20 years


Endon Roofing are fully licenced trained installers of Protan PVC Single ply membranes which are installed in warm roof construction, whereby the structural roof deck is covered by a vapour control layer, insulation and then the membrane. The vapour control layer is installed between the structural roof deck and the insulation in order to prevent water from condensing within the roof system, which would compromise the roof system’s thermal insulation capacity and ultimately cause the roof to fail.

Manufacturer’s warranties are available from Protan, which cover all materials and components installed by Endon Roofing. Standard warranty lengths range from 10 to 20 years.

Protan UK Limited only supplier’s materials and components to approved partner roofing contractors who employ Protan-Approved installers. All of our roofers are fully experienced and approved Protan installers.

Protan manufactures a variety of PVC single ply membranes for different uses, including:

  • Protan EX PVC Single ply Membrane – suitable to be installed over old roofing underlay
  • Protan SE PVC Single-Ply Membranes – suitable for new-build and refurbishment projects

End use:

This must always be considered, what is the flat roof to be used for? A balcony requiring protective walkway mats, installation of solar panels with specific weld able solar brackets to the single ply membrane. These factors need to be considered when the flat roof is being constructed.


A good quality membrane fitted by a contractor who is trained and approved for that system will help ensure a quality flat roof is achieved.
No flat roofing system will be the right choice for every situation. For this reason, you should carefully examine all factors about the building, and the expectations of the roof.

Endon Roofing only employ fully qualified and trained installers for all our flat roof projects.

Choosing the Right Roofer

With so many companies offering flat roof services it’s important you have confidence in the people working on your project. Visit the ‘our work’ page to see our most recent projects or alternately, chat to one of our roof experts by calling 01924 270 822.