At GNR, we undertake a significant level of roof related joinery on a daily basis. We do not specialise as a firm of joiners but are capable and equipped to undertake such joinery work required to complete our roofing projects. Usually, the joinery work that we undertake is limited to specific items, often needed to facilitate the installation of certain roof details. The list below outlines the type of joinery work frequently undertaken by our teams.

  • Installation of new valley boards.
  • Installation of new gutter substrates.
  • Installation of new flat roof decks.
  • Replacement of rafters where defective.
  • Construction of dormers.
  • Repairs to dormers and timber windows interfacing with roof areas.
  • Replacement roof structures.
  • Replacement timber gutters.

As with all of the work that we carry out, the use of quality materials, coupled with an eye for detail, ensures that all of our joinery work is carried out to the highest possible standards.

Should any specialist profiling or timber sections be required we also work closely with local joinery specialists such as Houghtons of York and Peter Thompsons to ensure we are able to provide the most appropriate solution.

Valley Boards

Valley Boards if the shape of a roof requires a valley it is imperative that moisture does not penetrate at any point in the valley construction. To ensure this does not occur DPC will be installed along the length of the valley created.

This is then covered in Lead lining followed by an overlap of felt and then finally the tiles. Valley Boards are installed to support the weight of the DPC and Lead. Roof rafters are often notched to accept the new valley boards.

If not installed correctly the Valley is one of the most prone to leak areas of a roof as it is the area in which water is directed towards rather than away from therefore correct detailing and build is essential. A common misconception is that the mortar bedding will prevent water access, however, a valley should work even without mortar.

Valley Boards GNR Roofing

Flat roof deckMore Details

A Deck is not only found on a boat it is actually the structural substrate of a flat roof and should be built to support the static and dynamic design loads as well as any load occurring from construction including machinery and plant.

All decks should be built of adequate strength to ensure structural integrity and provide ample support to the chosen roof coverings.

Timber Boarding

Softwood timber boarding is a traditional material used for the deck, It is important that the timber used should be;

  • Natural species derived or preservative-treated in accordance with BS EN 599-1:2009
  • At least 19mm thick
  • Double nailed at each joist
  • Laid using staggered joints

Plywood for flat roof deck

Should be of at least marine grade and suitable to external users to BS EN 636 plywood boards used for the deck should conform at a minimum to;

  • 18mm minimum thickness
  • double nailed at each joist
  • laid with staggered joints
  • provided with expansion gaps of 3mm between boards.

cold deck flat roof

Cold Deck Roof

warm deck flat roof

Warm Deck Roof

Visit our flat roof section for more information about flat roofing.

Flat Roofing

Replacing roof rafters and all cost

Roof rafters are structural timber sections that stretch from the ridge or hip to the wall plate, downslope or eave. And are designed to support the roof deck and coverings. A pair of rafters is known as a couple. In housing construction rafters are usually made from wood in some properties you will find that the rafters have been left exposed as a feature.

In modern buildings, preference has been made towards trussed rafters on the basis of cost and economy of the materials used coupled with off-site manufacturing and ease of construction.

Rafter and joist systems are made up of two sections that run directly below the roofing surface and give its shape, while the joists span the gap between the two rafter ends and support the whole thing. Over the years roof rafters can wear and rot and you may require a replacement. Replacing existing rafters without removing the roof requires carpentry skills.

Roof Trusses and Rafters?

Trusses and rafters are both assembled ahead of being installed onto a roof. Trusses are made in a factory using pre-engineered structures and joints. Rafters are assembeled at the site. Rafters contain two main outer beams which support the roof structure.

How much does it cost to replace?

Repair costs average depending on the scale of work and the damage caused including Rot, Water, Insects and even joint failure may cause the roof to weaken it is best to get a roofing professional to take a look at the job and provide you with an accurate quote.

How far apart are roof rafters?

Typically they would be 12, 16 or 24 inches apart these spacings are measured on center.

Wood GuttersMore Details

Wooden guttering on property provides a traditional aesthetic. However, to prolong its life and reduce the frequency of decoration, we prefer to line such timber gutter in lead. The detail uses a traditional off the shelf timber gutter which can be decorated to suit your property.

The lead lining is then added inclusive of a perimeter stainless steel clip to the leading edge. The key with this detail is to leave the profiled sections of the gutter as visible as possible. Further, such a lining should be installed up to the roof slope by 300mm, this will then be covered by the tile or slate roof covering.

The example depicted by the images presents a good example of how a timber gutter should be used. Importantly, Lead Sheet Association Guidelines should be adhered to, any lead installed should be allowed to move by way of rubber expansion joints if the gutter needs to be continuous.

Moreover, it is possible to use timber guttering without lining it in lead, however, it should be accepted that its life will be reduced. Often, a bituminous paint is used to line the internal surfaces of timber gutters.

Timber guttering can also form an ideal solution when looking at replacing your lead bay. Traditionally most lead bays would have used timber gutters to account for the external corners of the bays. Over time, householders have tended to replace such with plastic gutters. It is our view that lead bays, especially on Victorian Terraced Properties, for a key feature.

As such, we stripe to reinstate timber gutter details, lined with lead, whenever we replace the lead roof to a bay window.

Wood Gutters
Lead Lined Timber Gutter
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Wood Gutter
Wood Gutter Bay Window
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Dormer Roof ConstructionMore Details

A dormer is usually made from wood. The main structural parts that form a dormer are the roof, side walls and front which faces outward.

Dormers and planning permission Planning is not required provided that basics are followed as detailed here.

roof dormers
Dormer roof construction

Contact GNR Roofing

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