Fanlight commission for Grade I listed Gatehouse, Buckinghamshire.
David R Agnew, respected Craftsman Decorator from Newport Pagnell in the UK is back to tell us about the history of the fanlight and the work involved when he was commissioned to restore one in a Listed Gatehouse.
Introduction by Client/Architect
Tyringham Gateway was built in 1794 to the design of the eminent architect Sir John Soane and despite its small size it is acclaimed worldwide as a monument of European importance. Indeed, the late poet and renowned architectural historian Sir John Betjeman considered the Gateway and its close neighbour Tyringham Bridge as “the most perfect small buildings I know in England”. Unsurprisingly they are both Grade I listed buildings.
By the mid/late 19th century – less than 100 years after its completion – the Gateway stood uninhabited and unloved with its sash windows and entrance doorways blocked up with stonework. Fortunately in 1909 the building underwent general repairs and improvements when the original late Georgian entrance doors and fanlights were removed and replaced with new. Sadly no photographs of the originals have been discovered however it can be safely assumed that the semicircular fanlights would have had very narrow astragals or glazing-bars, which were fashionable in the late Georgian and Regency eras. Regrettably the Edwardian replacements were crude and heavy-handed, totally alien to Soane’s refined joinery detailing.
Precedent studies of other Soane buildings show that he frequently created metal (rather than wood) fanlights. These involved the workshop fabrication of compound glazing-bars or astragals, in which narrow moulded ribs of malleable cast iron or lead were crimped onto thin webs of flat iron or brass, resulting in a very fine and delicate appearance. One manufacturer of these astragals in the late 18th century was the Eldorado Company in London.
Knowing that David Agnew was an experienced craftsman accomplished at creating present-day leaded lights, I asked him whether he would consider making three fanlights based upon the Eldorado pattern for me, assuming that (as the Eldorado Company was no longer in existence) we could source the essential malleable iron or lead ribs. Soane frequently used pale yellow or amber stained glass in his fanlights and rooflights and a joint decision was taken to do the same in order to increase “authenticity”.
Retired conservation Architect.
Fanlight commission for Grade I listed Gatehouse, Buckinghamshire.
Fanlights are not particularly unusual, even leaded glass panels – each displays a certain uniqueness. The thing most unusual about these fanlights is the system employed. For craftspeople working on old buildings, this system was only employed for a generation and was left to obscurity some two hundred years ago! I feel it is important that fellow craftspeople will be able to identify surviving fanlights and afford the recognition and respect they deserve through passing on this knowledge.
The following project is by no means the protocol in the manufacture of these special windows, I merely wanted to document the way I went about making these ones, to achieve the desired results and would hope it is helpful to anyone else taking on something similar.
Further reading & information can be found within this excellent book – Fanlights – an architectural History by Alexander Stuart Grey & John Sambrook. ISBN 07136430779
A GENERAL AND POTTED HISTORY ABOUT THE FANLIGHT
Fanlights have nearly always been a feature above front doors, never more so, during the Georgian and Victorian period. They were designed particularly to allow natural light into narrow entrances.
The early examples, had very thick glazing bars, but during the late mid and late Georgian periods 1760 – 1810, there was almost a competition between designers and architects, on who could come up with the most elaborate designs & with the thinnest glazing bars.
Timber, having limitations as to the elaborate patterns that could be achieved within a curved aperture for example, persuaded innovation to dictate manufacture, from a malleable material, a thin profile from lead. These are sometimes known as ‘Eldorado’ glazing bars.
The profile is an ‘Astragal’ and is just 10mm at it’s widest point, the webs, which are inserted into the back are brass in a lot of cases, as this is malleable and can follow intricate shapes. It is not uncommon to find steel ones, but this is mainly confined to straight bars or pre-formed shapes.
Something else worthy of note, is on some really elaborate and decorative fanlights, you can see garlands of wreaths and ‘Adam’ stile urns etc. one famous fanlight, would be 10 Downing Street, London. If you look carefully, you can see in the middle, some curved leaves, these are made of cast lead.
Anyway, a potted & brief history.
Here is quite an elaborate example, featuring garlands and floral motifs. Circa 1780. Before and after restoration.
Another example in for repair and again showing floral motifs
I was commissioned to produce three fanlight windows for a grade one listed Gatehouse, Buckinghamshire, England. Built in 1794 and designed by Sir John Soane. One of the fanlights commissioned is an internal feature, dividing a bedroom and ensuite above a mahogany door. The glass consists of two different shades of amber, with blue slips around the perimeter – which is a typical Soane feature. The other two fanlights are above external entrance doors where I had to make alterations to the frame, more on that later.
Having being briefed & then commissioned with this project, I then had to source the material, as lead glazing bars are not commonly available. Stumped on how to find the obscure materials needed, I thought I would explore the idea of making my own and to see if I could. I first of all would need a mould, I used my router and suitable profile bits to rout grooves in a peace of maple wood – I had read somewhere that maple is quite resilient to heat, which would be ideal for a mould.
Router bits and the resulting astragal cast lead profile in
maple wood mould.
Router bits and the resulting astragal cast lead profile in maple wood mould. The results of the casting were reasonably okay. However, I had a problem with trying to work out how I could get a groove in the back for the brass webs. Whilst I was casting and having a dabble with lead, I thought I would try my hand at some of the ornaments which are found on fanlights. I did not have any elaborate moulds made from maple, so I used air drying clay to make my moulds because it is unaffected by the molten material. I simply found various applique ornaments kicking around the workshop, some were wood and some were plaster, I just pressed them into the clay and allowed the clay to dry over several days. It is important that the clay is not damp because the lead can explode. I used a propane gas torch, normally used for burning paint off, wedged between bricks and rested the iron ladle on top to heat and cut small pieces of lead until I filled the ladle and melted enough to fill the moulds. I have in the past, also used fine sand to cast ornament.
Should a new ornament be needed to repair a missing or damaged one on a fanlight in situ, then my method would be to take a latex mould from the existing pattern. I would then fill the latex and make a plaster proto type, then use this either press in sand or a clay mould prior to casting in lead.
However, I believe there are other moulding materials, which could be explored, such as resin. But for me, lead would be the honest route in order to restore.
Practice cast lead and clay moulds together with the iron
ladle for melting the lead.
Anyway, apart from all the experimenting, amusing as it was, Indeed to get on with the project in hand to execute it as professionally as possible. So………….we move on to the task.
I had the beads extruded by special order and to my specifications by a company specializing in the manufacture of lead came for the ‘stained glass’ industry – to which I also dabble.
The lead arrived in 1000mm lengths all coiled up. The brass is 0.9mm thick and 18mm width, which I managed to source from a trade stall dealing with scrap metal at a country show and steam rally. I think it might have been used for the decorative banding used to go round the boilers on the steam engines!!
Photo 2 shows the brass inserted into the groove, in the back of the lead bar. The lead itself, shown coiled up in photo 1, is 10mm in width. However, once it is uncoiled from manufacture, I hold one end in a vice and then pull the lead to straighten it. This also stiffens and as a consequence reduces its width to 8mm.
We now move on to making the window to fit its intended aperture. This starts with a full size working drawing, which has been checked for fitment. The lead, after having been uncoiled and stiffened, is manipulated and placed over the lines of the drawing. It is held temporarily with horseshoe nails – because these have a flat side – until the whole lead skeleton of the window bars are laid out.
To fix the lead joints, I cleaned the joints with a wire brush and rubbed a tallow candle over the joints as a flux prior to soldering. Once this procedure is complete, the whole window is turned over so that the brass strips can be inserted into the groove to form the webs for the rebate. I use plumbers acid flux at each joint prior to soldering with lead/tin solder. This really does stiffen the whole window panel considerably. All the joints are then cleaned up; a certain amount of delicate cutting back is needed in order to maintain the lead profile – Photo 7. The glazing bars and the brass webs are then thoroughly degreased prior to the application of cellulose primer.
We now move on to prepare for the glazing of our new window. The glass needs to be cut accurately as there is little margin for error, with the rebates being so very narrow, plus, cutting concave sections can have its risks too, as this has to be done by hand and not against a straight edge.
Turning over the window and working from the back, I lay the glass over for each section. I am able to see through the glass and proceed to run the cutter just inside the web line, making a ‘score’. A consistent score is required for the glass to then be taken aside, where pressure is placed on the score to which it will break – hopefully! I cut all the glass for each individual section, and then number each piece.
We are now able to proceed with fitting the already cut glass. Using ordinary linseed oil putty, the rebates are run with a bead to bed the glass in. photo 8 & 9.
Having bed all the glass in each aperture, we proceed with running a bead to create a face putty. This wedge shaped fillet will hold the glass in position. The rebate each side of the brass web is less than 3.5mm. When facing the putty it is extremely important that the putty line next to the glass, is kept back from the rebate by about 1mm, or it will be seen when viewed from the front, which is unsightly and undesirable.
The whole panel has been designed to fit in a ply sub frame or a kind of sash, which will fit snugly into the rebate of the main doorframe. Photo 12 may demonstrate this, by showing the outer perimeter from the inside, where it has been fitted to the sub frame by the use of escutcheon nails through the outer brass webbing and into the sub frame.
After installation, I applied mid brown eggshell finish to both sides, followed by a translucent dark brown eggshell to simulate the colour of the door and to achieve a ‘woody’ effect.
The finished window now installed as an internal feature to divide two rooms. We now move on to the other two fanlights, which will be above two external doors. Built in exactly the same way as the internal fanlight previously. The only difference is that the main door frame had to have subtle alterations to accommodate the fanlight panel.
Previously, there was an existing fanlight, which had four divisions and was installed during the Edwardian period. Inappropriately thick glazing bars and completely out of kilter with the refined design details of the building. Unfortunately, I have no pictures of this, but I altered the head of the frame above the door to incorporate a nameplate for each Gatehouse Lodge. A design detail by way of applied reeded moulding, which is contemporary for the building as there is evidence on other buildings designed by the same architect. Here is a clearer picture of the sub frame, mentioned earlier. Photo 15
Photos 16 & 17 show the fanlights in their external position, facing all the weather can throw at them. They have been protected with several coats of Sikkens Cetol BL, a water-based hybrid satin finish BS 12, B29. The signs are of course, gold leaf.
A shot from inside looking out. Amber glass, this time in monochrome with no varying shades or blue perimeter slips.
Here is the overall picture, complete
with door and masonry
to frame the effect.