Durable Roof Systems & Wet Room Solutions....

What is G.R.P.?

G.R.P. Glass Reinforced Plastic (Fibreglass) a composition of resin and chopped strand matting.

G.R.P. has been around for many years, used in the construction of boats, garden ponds and adventure water slides.

Over the past thirty years, G.R.P. has been used in the building industry as an alternative to lead and bitumen felt for flat/pitched roofs, valleys and gutters.

  Brad Valley

Above a typical tin/zinc lined valley, used over many years in agriculture, commercial and industrial buildings. Over the years the metal surface has badly rusted and delaminated, causing weakness to it’s structure and then allowing water to penetrate the structure within causing untold damage to the contents within the building.

Luckily this was noticed in time. The existing surface was cleaned to remove any lose materials, cracks and holes were taped and patched, before a 3 layer (1800 grams) lay up of G.R.P. lined over the existing surface, achieving new strength and making the valley watertight once again.

G.R.P. is available in a wide choice of colours and various finishes, including non-slip covering, which makes it ideal for waterproofing balconies and roof terraces.

Flat roof
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complete grp valley

The advantage of G.R.P. over traditional materials is that you have a product, which is flexible in application, being able to cover awkward returns and steps. It leaves a seamless, watertight joint, offering you a maintenance free finish, with peace of mind against leaks for years to come.

Fire Retardant Systems to BS476 part 3 F A.B. are also available, approved by Building Control, used where adjacent buildings are within 9 metres of the structure.

Leaking Wet Rooms are no longer a problem with G.R.P.

Unfortunately bathroom, toilets and wet rooms are often prone to leaking . The water leaks are concealed within the fabric of building; in the floors, walls and ceilings, which offen goes un-noticed, causing wet rot, leading to structural defects to supporting floor joists if not rectified.

We offer a GRP Wet Room System, which is ideally suited to waterproof sub floors prior to tiling.

GRP Wet Room SysyemGRP Wet Room System

Above: G.R.P. Wet Room System installed, then tiled ~ suitable for bathrooms, shower floors and wet room insulations.


For a free quotation Telephone (01305) 777 200

Email: grp@build-craft.com

Download G.R.P (Fibreglass) Roofing Portfolio pdf. HERE


Picture Galley

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Above; construction of G.R.P. Fibreglass roof covering.

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Above; completion of a G.R.P. Fibreglass roof covering.


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Above; G.R.P. Fibreglass roof covering.

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Above; Velux Rooflight, incorporated into a G.R.P. Fibreglass roof covering.

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grp velux x 3grp velux x 3 2

Above; G.R.P. Flat Roof, incorporation Velux Rooflights



Organery GRP Roof

Above; Construction of an Organery Garden Room with Reflex Rooflight, with a G.R.P. roof.

\grp \Reflex Glass Rooflight GRP Reflex Glass Rooflight 2

Above; G.R.P. Flat Roof, incorporation Reflex Glass Rooflight.

Below; Dormer Canopy with defective felt roof covering, recovered with G.R.P.

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Before........................................................     After


 grp valley

grp valley completedGRP Roofing

Above; 1800 gram G.R.P. application to back gutter abutment.

New single storey extension back gutter abutment to the existing property traditionally constructed by on site carpenters, (note the lead flashing/cavity tray), this must be incorporated within the build, or chased into brickwork after the G.R.P. has been installed.

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Above; G.R.P. Fibreglass Roof Valley. 

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Above; G.R.P. overcoming awkward configurations, maintaining a seamless joint. 

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Above; G.R.P. application to repair and strengthen a leaking commercial valley. 

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Above; G.R.P. Valley - one seamless, watertight joint.

Existing tin/zinc valley lined with 1800 gram lay up of G.R.P. to busy industrial/commercial premises in Glastonbury. 


GRP Reformed Fascia

Above; For the ultimate finish was can manufacture G.R.P. fasia boarding which can be can be produced in wide choice of colours and are made to order.

Usually when it comes to renew a leaking flat roof, the fascia boards and trims are also showing signs of decay or neglect.

This is why we have designed preformed G.R.P. fascia trims, which are fitted to the perimeter of the roof, once the boarding is made sound. Then and inner surface of the trims are keyed to allow a mechanical joint between the trims and the ‘wet laid’ G.R.P. covering (see data sheet).

Specification data:

 Standard Roof Lay-up: 3 layer (600) 1800 grams
Fascia Board and Trims: 2 layer (600) 1200 grams 

GRP Roofing





Download G.R.P (Fibreglass) Roofing Portfolio pdf. HERE

For a free quotation Telephone (01305) 777 200

Email: grp@build-craft.com


The Guild Of Master Craftsmen HERE

Images & photographs are for illustration only.

Health & Safety information is available on request.

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