Major rebuild of a bay window

This bay required extensive refurbishment. Cutting out of most of the bottom 20% , new windows, removal and repair of all the leaded glass before re-fitting.
and the introduction of secondary glazing into the leaded windows – the lead came had perished. New cills.
Was it worth it? well an 8 light timber bay made to measure worked out at over £12.000 this project came to under £7.000

A solution to Double Glazing in wooden windows

Some exciting developments have been made in Double Glazing technology. And finally a solution to retrofitting traditional single glazed wooden windows with a double glazed unit has been developed. It is now possible to have a 6.7mm or a 7.7mm clear double glazed unit. The statistics are impressive.It’s actually better at insulating homes than double or triple glazing with an impressive unbeatable U value of 0.7. The higher the ‘U’ value the less its insulating properties.It’s also better at sound reduction than double or triple glazing with a sound reduction of 35db. The higher the ‘db’ number the better it is at sound insulation.Also the internal pane temperature outperforms double and triple glazed units.

The valuessingle glazingslimline double glazingdouble glazingtriple glazingnew 6.7mm
light transmission9080807180
sound reduction2931313235
internal pane temp with outside temp1c13.6c15.7c17.28c17.7c

This glass can also be fitted  into frames using putty which means that retro fitting into heritage windows is now possible.These double glazed units solve the problem of retrofitting and basically all that I have said and written about not being able to fit a double glazed unit into a wooden window without compromising the integrity of the window itself have now been overcome. I will say though that these units are not cheap but they do come with a 15yr guarantee which is in itself way ahead of conventional d/g units.                                                                                

16th Century windows

16th Century windows
Its nice to come accross such delights. The customer asked for a survey of these windows and I was suprissed at their condition some areas require a bit of attention particulary on the Oriel window which has a established mini forest of foilage hanging down. This will have to be removed.Repairs were undertaken in the 1950s and you can see the ‘slips’ put into place where rot or damage has occured. With a build date of around 1550 these windows made from English Oak stand as testimant to the durable caracteristics of timber and in particular Oak windows.I was informed that the leaded glass dates from the mid 1600s. It could be the case that prior to the instalation of the leaded lights oiled cloth may have been used as a weather proof curtain which was the case in many buildings of that period.   

A stained glass window in Southampton.

A particularly tricky project with possible issues arising from the stained glass segments falling out or worse still breaking.
The stained glass itself is in a very ‘tired’ condition with the lead cames shot and the cement between the cames and glass cracked or missing. This is in addition to the rotten timber windows.
Normally I would take out the windows and glass and rebuild but that would entail something in the region of 200 hours labour. The windows also have not been opened for at least 30years and I was not going to attempt opening them.After some thought I decided to tape up the glass inside and out and then tackle the repair of the timber. Taking my time using specialist cutting blades set on a very high speed to reduce vibration I replaced the rotten timber with new. Thankfully it worked.

On a separate note I advised the customer to insure these as an extra on their household insurance as the replacement costs would be somewhere in the region of £20,000 if the worst was to happen and a house fire destroyed the whole lot. Lead has a low melting point. 

Box Sash Diamond Lights

I came across this beauty whilst stopping for lunch in the west country on my way down to Cornwall. I have described this as a Box Sash Diamond Light which is something I have never seen before. The Diamond design is not unusual in fixed and opening windows but in a sash window it is. There would be a considerable amount of work involved in manufacturing and glazing of this window sadly now in a poor state of repair.

Box Sash Diamond Lights

My guess is that eventually it will be replaced by a plastic unit, the building itself did not appear to be unusual or of historic importance so its probably not a listed building or window. I did knock on the door hoping someone would answer and throw some light on the subject but no one was in. So I stood in the public car park around the back of the building lodged between a parked car and an opening in a fence and done my best to take this image without drawing attention to myself. I did wonder what would I say if challenged by the police I would probably try and draw their attention to the design and aesthetics of this window and my website. They may come to a different conclusion! My wife incidentally wanted nothing to do with me at this point.

Yorkshire lights

A popular choice in late 19th and early 20th century buildings in the North of the UK, it is uncommon to see an example of the Yorkshire Light window in the South.
My understanding is that the design originated as the name suggests in and around Yorkshire. Openings for windows were often wider than their height due to dwellings in the North often being squat in comparison to dwellings further South. This no doubt was due to being exposed to the elements particularly on hill sides. A traditional sliding sash window requires height to be able to accommodate the weights and pully wheels to operate up and down.
This example required new shoes -the sliding windows run along Oak or metal runners fixed to the cill and housed in a rebate cut to the underside of the bottom rail, known as a plough groove . I also added draught brush seals set into carriers that eliminated draughts and reduced outside traffic noise.
In an edition of The Practical Woodworker dated 1929 it describes this style of window as being ‘very satisfactory in every sense’
I agree. They are a pleasure to operate pleasing to the eye and function without fuss. The customer had no idea of their rarity in the city of Southampton and was pleased with the end result. My only other experience of Yorkshire Lights in this part of the world would be a row of farm cottages that I worked on many years ago north of Winchester.

An opener damaged by wet rot

An opener extensively damaged by wet rot. The bottom one third of the window was completely rotten due to wet rot. 

The window although under a thatch overhang so set back by around 2ft (600mm) from the rain had suffered. I couldn’t work out why this was the case.

When I visited the customer to look at the job I thought perhaps there was a damp problem with the wall a traditional lath or perhaps an issue with rain from above through the thatch but if that was the case then the rot would occur at the top of the window not at the bottom.

I rebuilt the bottom 30% of the window and then refitted.

It was then that it became apparent why it had rotted. A wheelie Bin was placed in front of the window which was removed on my initial visit. When I finished the job it was replaced and the customer informed me that that’s where it always lives. The thatch overhang which has no gutter was immediately above, in heavy rain the water pours off the roof and continues to drip long after it has stopped raining the water was hitting the bin lid and splashing back onto the window. The bin had to be found a new home.   

New lease of life for a neglected window

Having been advised by a local council listed building department that they had received a number of complaints about a run down property the customer finally took action.
I was advised that these windows had not been touched or opened since the 1970s. As you can see they are in a pretty poor state although surprisingly little rot was present.
All the glass had to be removed, and rebates raked out. The joints required gluing up and clamping. The glazing beads needed replacement partings -that’s the timber between the glass and putty that forms part of the glazing bead. All the various layers of paint had to be stripped, a tedious task.
In total 120hours were spent on this one box sash window and frame

The finest Gothic revivalist window

This is probably the finest example of a Gothic revivalist window that I have ever seen.
I came across this sash window whilst on a weekend break in Ely, Cambridgeshire. My reason for visiting this city-the second smallest in Britain, was to see the Cathedral and the Stained glass museum within.

finest example of gothic revival windows

This beauty is in the high street above a building society. The Tracery- that’s the timber elements that support the glass is truly extraordinary with its hidden intricate joints dividing the whole window into symmetrical perfection.
The Angel lights – the upper panes of glass on the curved window section, from what I can determine are a combination of fused and painted glass resulting in an outstanding visual display of colour and patterns. And to top it all the Crockets- the figurative carvings and frieze that adorns the frame. It does not get better than this.
I stood there for some time admiring this masterpiece of joinery and glazing. My wife does think that I am slightly odd to get so carried away with a window! But for me this is art.
I imagine it was made during the revivalist period for all things gothic say around 1820s /30s. I can only hazard a guess at the extraordinary effort that went into designing manufacturing and installation of this piece. All for the expression of love for a style called Gothic.
Sad to say that I can see areas that do require some work, particularly the putty which if left will continue to break down, crack and allow wet rot to take a hold. I do hope that someone is going to look after this for future generations to admire.

Another Gothic arch window
figurative carvings and frieze that adorns the frame
Carved rose details on the pediment

Leaded Windows repairs

This was a challenging project. The leaded windows had extensive rot to the bottom rail and both the left and right hand stiles. New windows were made.
Because of the long term exposure to high moisture laden timber frames the lead cames around the edge of the glass had deteriorated and fell apart when they were removed. New edge came had to be soldered and each piece of glass recemented as these were leaking.
On top of that the bottom 20% of the actual frames and all the cills were very rotten. I did at one point question if I had taken on too much!
10 days later I stood back and felt pleased with the outcome. All in all this still worked out cheaper than replacement.
So this character property in Bitterne – Southampton built in 1912 managed to keep its original windows.


Leaded and stained glass window repairs

Window repairs with leaded glass edge.

An example of the service we offer in Southampton
repairing leaded windows

Leaded/ stained glass window repairs.
The method of making leaded or stained glass has changed little since its inception in the early part of the 11th century.
although technique and materials have advanced its nice to know that the basics remain the same today as they were applied back in the 1100s.

Old leaded window in need of repair

A common problem I encounter when removing the leaded glass from rotten windows is that the lead solder joints break or the edge came breaks as the putty is removed.
A came is the lead between each piece of glass.
Also I do come across some lead glass windows, particularly older examples where the lead came edging has perished.
Other issues encountered can be leaking lead joints and sagging lead came.
The lead glass shown here had broken joints and perished edging. Rather than taking the whole piece to bits and starting again – which is a time consuming job; tacking the broken joints and re-seating the glass with paste to prevent leaks and building up the areas of edge that have perished takes less time and results in a satisfactory repair.

Circular windows

A opportunity arose for me to undertake some circular work. The window in question had been re-glazed approximately 10years ago.
Unfortunately the glazier did not measure the bend correctly and had to fit the glass ‘off centre of the bend’. This resulted in the glass having to be forced against the rebate and pinned.In turn this meant that the glass was under pressure to spring back to its original form. There is a certain amount of give in curved glass but it will always want to return, just like a spring.
This pressure to spring back resulted in the glazing bead between the two pieces of glass to break at the joints. I suspect when the glazier formed a mould for the replacement glass he/she took measurements from the inside and did not include the depth of the rebate. The piece was 24mm short on the length, the precise depth of both rebates.
I fashioned a new mould by taking out the second piece of glass which fitted correctly and transferred this shape to a piece of plywood.
The glazing bead between the two pieces was repaired using Oak tenons that were slipped into mortices that I cut out and glued.
Once I had the replacement piece back from the manufactures’ it was a simple case of fitting.
There is always a moment of anxiety when offering up a bend but this one fitted like a glove.

Window Cill replacement

This started as a small area of rot in one of the corners. But once I started It became apparent that the whole cill had perished.
The exterior walls had been rendered and the interior walls plastered after the window had been fitted. It would have meant either a re- rendered exterior wall or a re-plastered interior wall if any attempt was made to remove the window frame, so replacement was not an option.
The property which is a grade 2 is situated 100meters from the beach. All new work was finished in a marine primer and marine grade paint will be used.

Sash window rescue

About ten years ago these two sash windows had double glazed units fitted after the original glass had been removed. Because the original rebates that the old glass sat in was not deep enough, the contractor machined them so that they became deeper and allowed the thicker units to be fitted. This meant that the joints were reduced and their strength compromised – these sash windows should not have had double glazed units fitted due to their construction; there is just not enough stock to be able to do this. Also the rebates were not painted prior to the glass being fitted which meant that the sealant used did not adhere to the timber. Add to this the inadequate timber beads, the end result was a weakened window at the joints and the opportunity for rot to take hold once water ingressed into the rebate, due to poor adhesion of the sealant. Also there was no throat (a groove that stops capillary action taking place) underneath the bottom rail.
Some sash windows can be successfully retro fitted with slimline double glazed units but not all; it depends very much on the thickness and width of the stiles (side members) and the top rail (meeting rail).
For those windows that are too slim or too narrow, single glazing remains the only option. After all, box sash windows manufactured in the early and mid part of the 20th century or earlier were not designed to accommodate such double glazed units, just like a car built in the 1970s was not designed to accommodate air bags or many other modern features we now take for granted.
This is where secondary glazing comes into its own, with or without brush seals on the parting and staff beads and along the meeting rail. As I have mentioned several times in previous posts, thick curtains will certainly help.
With these two sashes, I managed to replace the bottom rail and glazing bead, along with the bottom 1/3rd of the stiles. The question of weakened joints I have solved by using an adhesive as the sealant between the glass and the frame at the bottom of the rebate – not ideal because if these units need to be replaced once they blow and mist up (and all double glazed units are destined to do this, even if its years down the road) then removal may be a challenge. As you may guess, I am not a fan of double glazed units in timber windows. Normally you can strengthen joints by: 1. inserting a wooden slip, which can be seen in one of the images that accompany this post, 2. inserting a loose Tennon, or 3. inserting two wood screws that secure the stile to the rail, but on this occasion there is not enough stock to undertake any of these options.

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Scarfing in

An area of wet rot to a 1930s window appears to be the result of either water ingress past the putty or insufficient primer used when painting a previous repair. As you can see I  made  a cut out of the effected area leaving in the piece that has the interior moulding it may have been a whole new window if the wet rot had eaten away at the moulding.

A new piece was then added and fastened with glue and screws, timber plugs were used to plug the screw holes. Not entirely necessary but a far more professional finish. Once dry the window was re-hung and primed.


Why Preserve historic windows?

windows of interest in southampton

There is pressure to replace wooden windows with PVC-u this has come about partly by plastic window industry which has heavily invested in marketing, with the often optimistic claim made to fit replacements  in one day to a whole property, and the promise of a seamless experience with out the need too bring in other trades, may seem an attractive one.

The term ‘worn out’ is often used by the salesman to describe the condition of original windows rather than an actual assessment being made and the whole idea of replacement is driven by a culture of fashion  and upgrades. This can result in inappropriate adaptations particularly in a conservation area as PVC-u cannot match traditional wooden windows.

Sections and proportions of historic joinery. Historic joinery would be represented in most  pre 1970s dwellings.

Windows are the eyes of a building and profoundly effect its appearance and in addition represent the artistic social and economic development of an area and also reflected in many cases the status of a dwelling and its occupants.

Due to the high quality of timber used in the original, old windows can have long lives, often I come across windows that are 100,150 or even 200 years old and are usually economically repairable. It would take many years if ever that you would get back savings on heating having PVC-u fitted, and energy offsets making PVC-u windows in the first place are enormous. Estate agents often refer to the fact that replacement of historic windows and doors to PVC-u threaten the value of your property particularly in conversation areas.

Types of glass found in historic windows

Broad Glass.

A method used widely in the 12 and 13th century found mainly in churches and cathedrals made by blowing a bubble of molten glass swung to create a tube this was then laid and flattened with  the ends cut. Once cool the tube was cut into small rectangular lengths of sheet glass.

Crown glass.

Molten glass was spun producing a disc examples exist from the 14th and 15th century but when the tax on glass by weight ended cylinder glass became popular. Crown glass was made up to the 20th century.

Cylinder glass.

A type of Broad glass but with advanced methods employed it became possible to make larger tubes, this method became popular up to the beginning of the 20th century and many examples exist in private dwellings of that period.

Polished plate glass.

Developed in France glass was laid on a polish table and ground and polished to produce a clear sheet as mechanisation was being introduced glass for the first time was becoming less expensive this method was employed between the 18th and 19th century.

Drawn glass.

Often referred to as flat sheet. Molten glass was drawn between a die a bit like the old fashioned mangle used to wring clothes producing a flat continuous sheet.

This became the industry standard many examples still exist. It can be identified by the mottled effect and bubbles unless your property was bomb damaged during the war years or through some other breakage  you probably have this type.  


Invented in 1950 molten glass is allowed to flow over molten tin it results in a completely flat and featureless product of exact thickness and characteristics throughout.  


Development in glass production from around the 16th century  was reflected in the appearance of windows. Pieces of broad glass were laid in lead quarries but buildings still had often only one window that opened whilst servant quarters and low status rooms were not glazed, a waxed cloth was used along with shutters to keep the night out.

It was not until the 17th century that casement windows with sliding sashes became fashionable and with the onset of larger sheets of glass it became possible to fit these into rebates within the frame and glazing bars with metal sprigs were employed to keep the glass in place and finished in putty to keep the weather out.

The earliest sliding sashes had the top sash fixed. The lower one slid upwards and was held in place with pegs.

Not commonly known is that  the double hung sash window that you see today was a British invention although the French like to think it was theirs! As they were the ones who came up with the bottom sliding sash.  Using counter weights both sashes could be opened enabling a system of ventilation to be employed. The earliest example dates from 1701 and by 1750 most new development employed this system.

Many variations of this theme were employed and being British ridden by class the better off had swept heads (curved) , bowed, and elaborate decorative glazing bars. This can often be seen in fan lights above main entrance doors which also were becoming popular and stamped on the world a message of status.

Both Crown and cylinder glass was used during this period.

Glazing bars also were going through a development from large chunky Oak members to slender ovolo and quarter circle mouldings this in part was due to the import for the first time of cheaper softwood mainly Scandinavian pine. By the 19th century glazing bars were down to 12mm wide with pointed gothic mouldings.

With the introduction of cheaper plate glass from about 1830 which was stronger and available in larger pieces the need for glazing bars was reduced allowing for larger areas of uninterrupted views to the outside.

Thermal upgrading windows

Energy efficiency for reasons of economy, comfort and, reducing carbon emissions are a major priority. Economy because we all want to save money and there is only one direction that fuel bills go. Comfort – who would want to live in a cold home with draughts which adds not only to the economy argument but also the emission part of the trilogy.

Carbon emissions in my view is the big one, an extra jumper or thicker curtains will mitigate to a certain extent the issue of comfort but carbon emissions affects us all.

The amount of energy required to manufacture PVC-u windows and doors will take many years before it is off set buy savings in reduced emissions achieved by installing them if ever and there is to my knowledge no recycling of these units which are now becoming a landfill problem.

A whole building approach by that I mean looking at all possible ‘heat sinks’ can help in reducing waste.

The heat loss from windows can vary considerably it depends on the size of the window in ratio to the external wall. Heat can be lost through poor installation and ill-fitting sashes, conduction through the glass and from radiation through surfaces.

Retro fitting draughts excluders and brush seals outlined else where on this site can dramatically reduce draughts, bear in mind draughts can move in two directions into the room and out of the room.  Research has shown that fitting these simple seals can have an 80% impact reduction. Another benefit also is the acoustic proofing that results from these seals.

On the subject of research, thick curtains the sort my mother used to hang at the beginning of every winter- they were made from a second hand stage curtain which once hung at the old Atherly Cinema in Shirley can have the same thermal impact as double glazing. Not that we all have second hand stage curtains but you hopefully get the message.

Incidentally double glazing multi-paned windows will not give you the same thermal efficiency as secondary glazing either as there will be thermal bridging through the numerous glazing beads and frame.

So in conclusion without the need for double glazing to be employed  a combination of the correct seals- that is compression seals for windows that close against the frame and wiper seals for parts that move against each other, sliding sashes come to mind. The closing of any gaps around the exterior of the frame. Curtains or blinds and secondary glazing will keep you warm and snug without compromising the aesthetics.

Balanced or Lifting Shutters

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The cords had broken on these shutters, and I could not locate the pockets to access the weights in order to re-cord them. I had to refer to a publication by George Ellis titled ‘Modern Practical Joinery’, printed in 1902, for the answer. As you can see, the pockets had been cleverly hidden behind the panel which I found surprising as I could just at a push get my arm into the cavity. Perhaps in those days arms were not so big, or this kind of work was undertaken by an apprentice with slender arms.

What I didn’t want to do was to take off the front panel to access these pockets; it’s been fixed in place since the 1850s. The windows are the original, fitted in 1796, but the balance shutters are a later addition. This was established by the presence of the original skirting board inside the shutter case. Also, the building was once owned by the Church and had a reliable record of works carried out over the last  two centuries.

Sometimes the pocket sits near the top of the frame, about 18” down from the pully wheels, which I now understand became the practice during the early part of the 20th Century.

Whilst doing this work it occurred to me what a fantastic way to eliminate drafts, light and noise. Those late Georgian / early Victorian designers really did think of everything, and the skill employed by the carpenters and joiners, with limited rudimentary  machinery, I can only admire and take my hat off to.

I am hoping that one day I will get an enquiry asking how can I eliminate drafts, light and noise with box sash windows fitted, as I would relish the opportunity to manufacture and fit a 21stcentury copy of such a practical solution to an age old problem.

There are modern day solutions that can be employed to reduce considerably the draft and noise problem associated with box sash windows, and these are covered in previous work and articles on this web site. I am happy to undertake such work but the elegance of balance or lifting shutters cannot be matched.