Lintels

from Lintels final 23.6.07.doc

last revised: December 13, 2007 12:23 PM

 

Bricks and Building Forms

All openings in brick walls need some way of keeping up the bricks above the openings. This may be an arch or a flat lintel of some kind.

Fig. A A brick wall with and without a lintel.
Fig. B The setting out of a brick arch with wedge-shaped bricks.
Fig. C The setting out of a rough brick arch. These are normal bricks and the wedges are formed with mortar.
Fig. D A ferro-concrete lintel, the modern solution to the problem. Some builders use steel lintels and wooden ones used to be common.
Fig. E A relieving arch used to carry the weight round to the sides of the door or window opening so that hardly any weight falls on the lintel.
Fig. F A section through the cavity wall in Fig. D. There is an outer skin of brick, a cavity for heat insulation and an inner wall of thermal concrete blocks. The damp proof course carries any moisture which has penetrated the outside skin out through the gaps shown above the lintel in Fig,. D.

 

Examples of Flat Lintels

 


A flat lintel in London Stock bricks

 


Another Flat Lintel made of specially shaped bricks, with
brackets supporting the eaves and a roof in clay pantiles.
Manor Road, c.1850.

 

These sets of bricks brick lintels were made at the brickyard and arrived in wooden boxes packed with straw. By this time the Fire of London Regulations forbidding projecting eaves were not being obeyed rigidly in the suburbs, so these eaves needed some support.

 


A cut brick lintel with a heavy brick keystone in Stoke Newington High Street.

 


Some flat lintels heavy brick keystones in Church Street

The wooden window frame is fully exposed instead of being hidden behind a layer of brick. These heavy keystones are typical of the Edwardian Period, just before the First World War.

 


A stucco lintel with a triangular pediment, supported on Gibb’s brackets

 


A splendid stucco door head in Stoke Newington Church Street

The stucco work includes dentil work (like teeth) inside the triangular pediment and below the canopy; a central mask with swags of flowers and fruit on either side; two elaborate Gibb’s brackets supporting the canopy, and an egg and dart moulding round the door. A drawing of this door appears in Dan Cruikshank’s splendid book, ‘The Art of Georgian Building’. Behind all this elaborate stucco is a simple lintel built into the brick wall.

 


The next door house is decorated with stucco in a Classical style,
Stoke Newington Church Street.

The bracket design under this canopy goes back to the timber joists in early wooden Greek temple. The Greeks copied these wooden shapes into their stone buildings and the Church Street builder copied them in stuco. The design is over 2000 years old.

 


Post War Lintels in Manor Road, opposite Grazebrook School.

The lintels are made of ferro-concretebeams with a row of brick soldiers above. The latter are purely for decoration, not strength.


A Post War Block of Flats at the corner of Town Hall Path, Albion Road.

Here the windows have ferro-concrete lintels but the soldiers have been dismissed. The result is just as strong, but plainer.

 


A block of modern flats in Yoakley Road made in grey brick

In this block of modern flats the concrete floor above acts as a lintel so there is no need for an extra one. The grey bricks are laid as stretchers, showing that theses are cavity walls.


A modern window with a ferro-concrete, or steel lintel completely hidden by brickwork.

 


The same sort of construction can be found in Brittany, another stone country
This is a heavy stone lintel in a stone building.


Relieving Arches


A relieving Arch

The weight is diverted round the arch and down to the ground. This means that there is almost no weight pressing down on the window head or door opening.

These diagrams show several types of arch and some of the formers used to build the arches.

Arches instead of lintels

Arches act as lintels, carrying he weight safely to the ground, and can be of many shapes.


1 Segmental arch with wooden former (centring) in place


2 Round (Roman) arch with centring in place and standing on two jacks which can then be lowered to release it when the mortar is set.


3 Three-centred arch. Here the word centre means a point where the point of the compass is set to draw the arc.


4 Round wooden former for a Roman arch


5 Another type of four-centred arch.


6 A Florentine arch. There is a row of these above a terrace of shops in Essex Road. They were made popular in England when Ruskin published his book The Stones of Venice, 1851-53. From then Florentine arches became popular and a number can be found in Stoke Newington.

Examples of Segmental Arches


An Arched lintel with a white painted keystone and supporting
abutments on either side. Manor Road, c.1850.

The abutments and keystone are probably all in Sandstone, which was very popular and relatively cheap at this period.


This is a curved lintel in bull-nosed glazed brick which is very hard wearing

 


A wide arched doorway to a block of flats, with a keystone and side buttresses,
Church walk c.1900.

 


A segmental lintel in the old Tram Depot at Manor House, c.1890

These unusual lintel blocks are in red brick. At first they might be taken for terracotta, which is a hard pottery, but the surface of these blocks has begun to wear. Terracotta has a harder surface which resists the acid London rain better than this. The liver coloured terracotta fronts of the 1900 London tube stations are very well known and are still in splendid condition.

The old Tram Depot has now been converted into flats.

 


A curved lintel formed with ordinary bricks, not wedge-shaped ones.

 


Similar egmental window heads but covered with stucco and,
no doubt,with false keystones.

 


Segmental arches and flat lintels from Dumont Road

 

 


Kersley Rd

 

 


A segmental arch of cut stone blocks with a keystone, in Brittany

 

A stone archway under construction in Brittany with three layers of stone, with larger ‘keystones’ at random intervals. The supporting former on which the stones were laid, has just been removed.

 


A segmental arch just cnstructed in stone blocks.

The inner wall is in thermal concrete blocks, so that this building which will soon look like the old stone buildings nearby, will be constructed in the latest heat retaining manner.

 


A Round-Headed arch made of three massive stone blocks, in Brittany

 


The house front showing the doorway and an equally massive window head
in shaped stone voussoirs (wedge-shaped blocks).

 


Sometimes segmental and flat lintels are used together.

Flat Lintels inside arches

The relieving arches carry the weight of the wall round the windows and down to the ground. This allows the brick work within the arches to be half a brick thinner than the outer wall. The cut bricks of these particular lintels and of the arch, are very thin, hardly thicker than tiles.

This form of construction gives an elegant appearance to the building with contrasting brick colours and interesting shadows, far more attractive than a plain brick wall.

 

Two arched lintels windows with cut brick lintels inside relieving arches,
in Stoke Newington Church Street.

 


An elegant round-headed window in Stoke Newington Church Street

The round brick arch and the lower wall of the house have been covered with stucco and lined to give the appearance of stone. Some early builders used to colour and grain their stucco walls to make them look even more like stone blocks.

 


Flat lintels with an elaborate weight relieving arch on William Patten School building, c. 1892

 


A Triple Arch which acts as a lintel
Grazebrook Road

These windows have triple arches, allowing the window to be wider. The arches themselves have then been decorated with stucco.

 

 

Here the same shape has been enclosed in a much larger stucco framework, with a top canopy supported on brackets.

 

 


Another Triple Arch in Grazebrook Road, heavy above but supported on light uprights.

 


A lunette window in the old Glebe houses, built by Widdows in 1835.
They were demolished in 1936 to build Manston House,
opposite the gates to Clissold Park.

 


An attic window supported by an arch.

The gable wall of this house is angled, giving this unusual arrangement of curves. As usual, these quadrant windows are hinge vertically at the centre. The semicircular window allows far more light into this attic room than any rectangular one could have done. The use of contrasting bricks has much improved what could have been a awkward gable end.

A Corbelled Lintel

A most unusual corbelled lintel in Grasmere, Cunbria

Detail showing the lengths of the stone courses and a keystone apparently suspended on nothing. This last is a mystery, held up by magic. Can there be a bolt through it?

Instead of a normal arch, with the different stones pressing against each other sideways, the stones here have been corbelled. Each stone presses downwards but, because they are long and only a small part of each one projects, they cannot fall. Corbels are often used to support beams, some castles have corbelled passages, but corbelled window heads are very rare.

 

Work in Progress

Main Index