Dormer Extensions & Conversions

Dormer Conversions & Extensions

Macclesfield roof dormer construction

Dormer conversions have flat sides and extend outwards from an attic roof.

Full dormers employ similar construction techniques to those used to construct single dormer windows, but on a larger scale.

Dormer loft conversions occasionally span half total roof width, and several windows are installed to light individual rooms.

Bungalows, Terraced and Large Houses

Dormers are a popular addition to bungalows because the second storey adds a significant amount of room at head height.

An extension to the roof of a terraced house may be a sole option if the back garden or yard has insufficient space for a ground floor extension.

Bungalow Conversion

In which case building upwards into an unused loft space will provide more room and increase property value. Terrace houses are unable to have the roof-line raised if loft height is too low.

In larger houses, a dormer conversion can add a luxurious room with en suite and significantly increase a property's value.

Bungalow Conversion

The additional head room at head height makes dormers ideal for use as a social space within larger houses, such as a living room, office or bedroom.

Dormer Roof Conversion

A dormer conversion structurally and visually alters your house and dormers almost always require planning permission and compliance with building regulations too.

If you are considering a dormer conversion for the first time the process requires:

• Loft and house survey
• Floor plans
• Planning and Buildings Regulations Approval
• Building Inspectors Approval
• Construction

Construction of Dormers

When extending the loft to construct a dormer it is essential that a roof's structural stability and strength is not damaged during the building process.

How to construct a dormer:

1. Validate building plans - before building work begins we ensure building plans are correct, particularly if externally provided.
2. Trimmer Joists - The roof aperture will extend across modified roof rafters and so timber roof supports above and below are installed. reinforced steel joists (RSJs) span the base and top of the dormer frame to support the weight of the ceiling and window (In truss roofs, rafters are not modified but replaced Contact us for details).
3. Dormer Cheek Construction - we attach vertical timbers onto existing roof rafters (either side of the roof aperture) specialist washers grip timber 'uprights' to create the dormer sides (dormer walls or cheeks).
4. Roof Extension - full dormers generally have flat roofs. Horizontal timbers run the width of the dormer and join uprights.
5. Cladding - insulating cladding to make the structure water and weatherproof is applied to the frame. Dormer cheeks are often clad with roofing materials such as tile or lead so the extension remains 'in keeping' with existing roof style. Options include:
   • roofing felt onto the timbers to provide an inner waterproof skin
   • matching tiles secured with nails applied across the lats
   • wood tiles secured with nails across the lats
   • Metal lead may be used to weatherproof and match flashings
6. Insulation board. Insulating board is intalled integral to the dormer frame. This maximizesthe lofts heat retention capacity. Insulating board is usually 50mm foil backed board and conforms to building regulations for thermal insulation.
7. Window. The dormer window is installed into the gable end. Double glazed windows in either uPVC, solid wood or hardwood are fitted and:
   • Sills made perfectly square and horizontal using spirit level
   • Angle of jambs made vertically upright
   • Window frame secured to the dormer frame with fixings
   • Gaps around window edges filled and sealed with cement mortar mix
   • Test windows for easy opening, locks, ease of operation
8. Plasterboard. Plaster-boarding of internal wall of dormer over frame and insulation boards.
9. Plastering and skimming - double application of plaster to ready the surface for a final skim and internal decoration.
10. Decoration - dormer conversion is decorated with paint or wall paper if required.

Dormer Roofs - Guide

Large dormer extensions generally require flat roofs as pitched roofs would tend to exceed the height of the existing roof.

Our flat roofs are built to last, we using only high quality roofing materials to create a weatherproof and sturdy dormer.

To increase light into the room designs can include a roof window within a flat dormer roof. Skylights allow more natural light into an extension.

Window Installation

The vertical windows we most frequently install are low maintenance, uPVC and double glazed.

Available in many styles and designs windows will match any design specified in building plans such as wooden frames.

All our windows are guaranteed water and weatherproof. Our experienced window fitters ensure watertight seals, flashings and frames.

Top Windows Designs