Offering a complete range of roofing services to you the customer.

Our comprehensive service include repairs, tiled roofing, flat roofing, felt works, GRP fibreglass roofing and fully glazed roofing. We can also provide roof lanterns, Velux window supply and fit, chimney repairs, fascia and guttering works.

GRP Flat Roofing

JWI Roofing is an approved Crystic GRP (Glass Reinforced Polyester) flat roofing installer who operates throughout the Harrogate area. For domestic jobs, we require no deposit and offer a 100% satisfaction guarantee.

All of our GRP installations have guarantees of 10 to 25 years which are underwritten by both the manufacturer and a leading insurance broker via the Confederation of Roofing Contractors.

Why would you choose a GRP Flat Roofing System?

GRP flat roofing systems have many benefits, including:
•  Durability
•  Low maintenance
•  Long guarantees (10 or 25 years)
•  Flexible usage
•  Simple no-flame installation

Why is GRP roofing durable?

GRP has to be durable. It is used in the production of boats and cars as well as building products such as pipes, sewers, water tanks and flat roofing systems. GRP was first developed in the 1930’s by the du Pont organisation and became widely used in the 1950’s. Since then, GRP flat roofing systems have earned an excellent reputation as a long-life replacement to traditional roofing materials.

To learn more about GRP visit:

Why is GRP low maintenance?

GRP flat roofing systems are seamless which means that there is a much lower chance of leaks during its active life. It’s also smooth which means that it’s more difficult for moss to accumulate. Finally, due to its tough durable nature it is easy to clean and does not break if you walk on it (within limits).

What do you mean when you say that GRP flat roofing offers high flexibility?

GRP is an exceptional flat roofing material. In addition, GRP roofing systems are fabricated and installed on-site (i.e. they are not prefabricated in a factory). For this reason they can be moulded and shaped to fit difficult areas. This is especially useful where there is complex detailing that other materials cannot effectively weatherproof. This includes pitched roof valleys, gully linings, pipework, roof-lights valley, box gutters, walkways and balconies.

Why is no-flame installation important?

GRP benefits from being a “cold-applied” waterproofing system which means that it can be applied in situations where there could be a high risk of fire or explosion. This could be important in large commercial projects.

Design considerations – Cold roof v Hot roof

Flat roofs fall into two categories. The first is known as a “Warm Flat Roof”. In this configuration the flat roof has a cavity between the ceiling and the roof insulation. The roof insulation is on the upper side of the cavity and the trapped air is warm, hence the name warm flat roof.

New buildings usually have warm flat roofs because current building standards state that flat roofs should have a minimum of 150mm of insulation boards installed between the ceiling and the roofing deck.

Benefits Include:
•  Low cost
•  Thermally efficient
•  Less condensation in the void

Disadvantages Include:
•  Additional height (Can be a problem with balconies)
•  Soft final structure (Can be overcome with extra decking)

A “Cold flat roof” also has a void between the ceiling insulation and the underside of the roof decking. In this case however the insulation is above the ceiling and therefore the air pocket is cold. This configuration was more common in buildings before 1990. It’s often impossible in old properties to accommodate a warm roof because of space constraints and a cold roof construction must be chosen.

Benefits Include:
•  Low cost
•  Hard finish
•  Lower profile

Disadvantages Include:
•  More expensive because of added ventilation and complex construction
•  Less thermally efficient
•  Edge detail trims and mouldings

GRP mouldings should be used where possible. These are standard prefabricated items that have a very accurate and uniform shape. GRP mouldings can enhance the appearance of the roof perimeter detailing. There are many different thicknesses and different profiles to suit most roofing projects and you should discuss this with your chosen roofing installer. GRP mouldings come in grey but can be painted to fit in with the design and colours of the building. Other examples of GRP mouldings include sky light frames (or up-stands), ventilation cowls and chimney stacks.

Fleece Thickness

A GRP roof incorporates a thick heavy-duty fleece and these come in two thicknesses.
•  450g/m2 fleece offers a 10 year guarantee
•  600g/m2 fleece offers a 25 year guarantee

Installation Process

It’s helpful to know the GRP flat roofing installation process:
•  Strip off old roof covering and dispose of to landfill
•  Inspect and prepare existing roof joist timbers and make good as required
•  Install 18mm tongue and groove OSB (Find out) plywood roof deck
•  Tape all exposed board joints
•  Install all perimeter edge detailing
•  Apply the GRP fleece in sections
•  Determine the optimum accelerator quantities
•  Apply the acrylic compound in manageable stages
•  Allow to cure
•  Apply solar reflective top coat.

Fascias and Soffits

You can now enhance the look of your property with low maintenance UPVC. No more climbing ladders and scraping off that old paintwork!

JWI Roofing can rapidly install new cladding boards that sit over your old existing timber, at a very low cost! Less than employing a painter to paint them again, and again!

Any rotting or damaged timber is removed and replaced, as required. New UPVC Cladding is installed to make your property stand out!

This will require very little maintenance in the future, leaving you free on those hot summer days, and not having to climb up ladders to restore the flaking paintwork when you should be having a BBQ.

Tiled roofs

Our very experienced operatives will carry out your installation with the utmost care and professionalism at all times, minimizing disruption to our clients. Should you require a complete re-roof of your property, talk to JWI Roofing.

There are many types of roof tiles on today’s market, be it natural slate, hand made clay, plain or concrete.

The choice is yours, but we will be able to give you advice when we come to give you an estimate.