Roof Types

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A basic photographic illustration of various roof types found within Great Britain.

❖ Traditional roof forms

Gabled

The side wall continues up to the roof ridge.

Double (multiple) gabled

These were common in large Georgian homes, where roof timbers large enough to cover the complete span were unavailable, or prohibitively expensive, but are still being built today for Aesthetic reasons

Hipped

Double (multiple) hipped

Half Hipped

Also known as a Barn Hip in vernacular and traditional buildings.

Gablet

Half hip and gablet

Mansard

Not to be confused with Gambrel, the mansard is double pitched to all four sides.

Gambrel

Also known as double pitch. Often confused with the mansard (above).

Outshut/Catslide

Where a smaller lower addition is added to a building, the new roof makes one continuous roof with the main roof, and is often at a shallower pitch to the main roof.





Side Outshut


End outshut

Lean to

Similar to an outshut with a small addition to the side of the building, however the roofs are not continuous with one another. Also known as a Pent roof

Mono pitch

A simple single pitched gabled ended roof.


Double mono pitch

❖ Flat roofs

Usually in mono pitch form, flat roofs are typically used in domestic house extensions, tower blocks, and service, public and council buildings where cost of build and ease of maintenance is a priority. This included such buildings as fire stations, schools and electricity substations. A roof is usually considered flat at 10° or less.

Popular due to their lower cost, low roofline and smaller volume, though not always popular in terms of aesthetics.

❖ Shallow roofs

Simple corrugated metal, plastic or asbestos flat or shallow roof, used on agricultural buildings and warehouses.

❖ Dormers

A Dormer is a separate smaller roofed structure protruding above the main roof, providing additional windows and space in the roof space or attic of a building.

Dormers are often retrospective additions to a building, the owner wishing to make more from their unused roofspace. In recent decades roof lights have often been added instead of dormers due to their low cost of build.

Dormer types;

Gable fronted dormer



Hipped dormer



Flat roof dormer
Sometimes known as a Box dormer



Shed dormer
A shallow pitch roof falling the same direction as the main roof.


Wall dormer
The main wall continues above the eaves line.


Round topped dormer



Circular windowed dormer
An Oculus dormer is typical of French classical architecture, brought to Great Britain.



Swept dormer
On thatched buildings.


Canted dormer



Rooflights
In recent decades it has become increasingly popular to install roof lights as a quicker and cheaper alternative to dormers. Made famous by Velux.

❖ Parapets

Used in combination with the roof types above. The main walls of the building continue up hiding the eaves of the roof. Often used on taller buildings, where maintenance to eaves is made more difficult. They were made popular in London after the building act of 1707 was introduced which banned the projecting wooden eaves to reduce the risk of spread of fire to neighbouring buildings. The style became fashionable during Georgian times.

❖ Curved

Agricultural buildings often used simple curved corrugated iron roofs.


They are now very popular amongst new buildings, particularly those on a large scale.

❖ Dome

❖ Specialized roofs

Conical Oast House roofs, designed to channel hot air up through the kiln.


Windmill pivoting roofs, often called 'Onion cap'


Opening

❖ Modern Roofs

Nowadays there are a large choice of materials used in roof construction, including different metals and glass which can produce interesting and imaginative shapes.

Saw-tooth

A functional variant of the Saw-Tooth is the Factory "Northlight" roof, where the steeper edge of each sawtooth is fully glazed and faces North. This was common in the late 19th and early 20th Century, when artificial light was expensive, and gave good illumination throughout a wide span structure. By taking the light from the North a more diffuse light was produced, which did not vary much during the day and which avoided overheating in summer

Hyperbolic paraboloidal

Folded

Butterfly

❖ Unusual roofs

Grid shell
Not particularly well used method of construction. The whole building structure is constructed from a lattice grid of thin wood or steel. It allows for more organic and unusual shapes.

❖ Materials

Clay Tile

Slate

Grit-stone

Horsham slabs

A local variation of slate roof in Surrey and Sussex, sometimes with triple overlap

Felt

asphalt

Thatch

Corrugated sheet metal

Profiled sheet metal

Asbestos

Lead

Zinc

Copper

often used on churches

steel

Green roof

Also know as 'Living Roofs'

❖ Further reading

The traditional roof forms section is inspired and aided by "Traditional Buildings of Britain" by R.W. Runskill


Wikipedia: Gridshell

illustrations © Oast House Archive (all rights reserved)

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