During the 19th Century, joiners considered wood as something more than a building material; this affinity arose from the fact that it was essential to their income and reputation: poor materials are also noticed more readily in a hands-on environment.

Formerly, owners of joinery businesses would nurture long-term trading relationships with importers of the best timbers, generally from the European Continent but also occasionally from the Americas.

Sash windows were found to last longer if they were manufactured from the slow-grown Baltic pines (pinus sylvestris) of Eastern Europe; more northerly latitudes grew botanically similar species though the climate often made for a less dense timber. The severe winters of Russia encouraged the strength and durability of the wood: it took longer to reach a harvestable state but the returns on longevity and consistency was worth the wait.

The design of the box frame window is completely different to its cousin the casement. Most notably the front portion of the cill is exposed to the elements constantly throughout the seasons year after year. This aspect of the design often led the most conscientious window-makers to specify the cill in a much more durable species and European Oak (quercus robur) was found to be ideal: it might change in the long-term, e.g. it is prone to hardening, yet it is virtually impervious to rot, fungus and insect infestation.

The combination of these timbers made for a long-lasting, high quality window with minimal maintenance requirements apart from the occasional lick of paint every few years. It might possibly be the case that the window you are replacing is original to the property and therefore testifies to how long these things can actually last.

The design of the box frame is relatively complex, being constituted of numerous parts, each performing a separate and essential function. Many parts were intended to be replaced from time to time by experienced carpenters and local timber merchants would hold these profiles in stock to avoid the cost and delay of getting them made up for each window – they are still available today – these are the staff and parting beads. The carpenter could confidently arrive for a day’s work with a handful of beading confident that it would fit into the grooves originally placed by the joiner.

We have thought about this partnership between workshop and site and decided that it is only right to continue this tradition.

Our parting beads are made of oak for strength and longevity and are of a section that can be bought off the shelf in the UK in the event of breakage or frame restoration.

Likewise our staff beads are of standard profile (with an additional layer of drought-proofing incorporated) and can also be easily replaced.
In the unlikely (long-term) event that the front portion of cill is eroded by extreme weather conditions, we have made up the cill in two parts so the carpenter has an easier time removing the damage and has a cleaner line to work to in his replacement efforts.

You might encounter window salespeople that extoll the benefits of ‘engineering’ all the timber parts of the products they offer – this, we believe demonstrates a fundamental misunderstanding of the original design and a reliance on suppliers that prefer a homogenized readily-available joinery material that requires little operative involvement in the windows they produce. Occasionally it might be necessary to laminate certain sections to achieve a given result but this must be done with empathy and understanding of how the window will perform in the years to come, it is not a universal panacea for guaranteed quality.

We believe we have taken all practical steps possible to ensure that your beautiful new windows will last for many years and that they are faithful to the rich tradition of British Joinery.

We urge you to read through our comments on Timber, this, we hope, should reassure you of the integrity of the materials used in the production of your new window; however, there are occasions and locations where having a choice in the wooden elements of your window are a good thing…

In certain extremely exposed and inclement areas of the British Isles, wind and rain will relentlessly attack the entire frontage of the window. Generally, the sashes cope with this well as their method of hanging allows them to ‘drip dry’, however, the outer linings (the bits between the sashes and the brick-work) do not have this facility and can, over time, degrade and rot. We have strengthened the critical point – the connection where the cill, pulley stile and lining coincide – with an oak run-away fillet, yet still this might not be enough in certain circumstances. We offer ‘Outer Armouring’ of the outer shell of your frame by specifying the entire exterior face in durable oak: this can be selected as a standard upgrade in the Price Calculator.


Although not common, box frames can be made of virtually any durable timber species – a good example of this would be the William and Mary Wing of Hampton Court Palace where beautifully tall sash windows were made from solid oak. We would be happy to research any scheme you can envisage and we will provide you with a price accordingly.

We would mention that, more than any other window form; the boxed frame is a ‘holistic’ structure, i.e. a change in one element will conceivably require a change in one or more of the other elements. The main concern will be weight: we have already increased the weight of the sashes by incorporating a second pane of glass in each, specifying hardwood sashes will increase the weight again. Sash ropes might need to be replaced by chains, pulleys might need upgrading and timber sections and joinery might need to be modified to achieve this new arrangement. These situations are not insuperable, we have encountered many projects where a customised approach is required, although it goes without saying that a higher cost must be expected for this level of ‘bespokery’.