Dormer Construction For A Loft Conversion

For the purposes of this article lets look at a typical flat roofed box dormer.

The Process in a Nutshell

Adding a dormer usually follows a well worn path with the first phase being for the builders to cut into the existing roof and removing the tiles and battens.

The structure itself is then put together with a timber frame that is then dropped into the hole.

Once the structure is in place the windows will be installed. The dormers flat roof is then built and put in place before the whole structure is clad with material such as tile, boarding or Upvc.

The Build

To a layman framing dormers looks very complicated and involved.

Fortunately thought most joiners or carpenters will have little trouble in putting together the timber studwork.

And there are good reasons why dormers are usually constructed from (soft) wood.

The first and probably most important point in using softwood for dormer construction is that the finished structure is light and also very strong. They can also be constructed very quickly.

The first step in dormer construction is to build the base plate or sole plate as it is often called.

The base plate is the length of timber to which the bottom of the vertical studs are fixed.

The base plate will then be fitted to a steel beam or possibly the wall if building up from the main wall.

The studs themselves will be made from 4x2 (sometimes larger) timber with no more than a 350mm gap between each.

Equal spacing is desirable but not always practical depending on the size of loft windows being used.

To accomplish this a timber head beam is used.

This beam runs horizontally across the top of the vertical studs and will support the loading from the dormers flat roof.

The built up sides of the dormer construction are called ‘cheeks’.

The vertical studs for the cheeks will be fixed to the rafters in the roof before being clad with tiles.

The cheeks are not load bearing as the base plate and head beam provide all the support needed by the new structure.

Assuming that you want a view, fresh air and natural light in your loft conversion then a suitably sized opening needs to be left in the timber framework though remember that extra vertical studs will be needed to support the window.

Weather Proofing

The first step in protecting the dormer from the vagaries of the British weather is to clad the framework with timber sheathing.

Plywood sheeting is usually used for this and its purpose is to provide a backing for the insulation as well as keeping out the wind and rain.

The final step in dormer construction is to fix battens to the sheathing onto which the final covering of tiles or lead sheet is fixed to complete the dormer cladding.

For more info see the related pages below or complete the form at the bottom of the page for a free no obligation quote from tradesmen near you...

Dormer Designs

How To Get A Free No Obligation Loft Conversion Quote

Dormer Construction Windows

Guide To The Loft Conversion Building Regulations

Gable Dormer

Eyebrow Dormers

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