Kya deLongchamps encourages the restoration of the endangered and highly symmetrical, period sash window. 

I HAVE a preference for solid wood windows and it must be said, attractive aluminium clad frames with timber interiors are seizing a market previously dominated by the no maintenance wonders of UPVC.

Defending the natural beauty, ecological strengths and current affordability of the wooden hearted, the same defence slams the conversation closed like a tightly engineered, five point locking casement — ‘wood doesn’t last’.

Unprotected by the dreaded ‘Minister’s List’ (affording protection to buildings deemed of architectural merit), and sometimes even when known to be on the list — centuries old wood sashes are still being ripped out and replaced with the cheap, flat faces of tilt n’ turn double glazed plastic.

Home-owners little realise that apart from the loss of the frames, the rippled, hand-made glass itself may be original to the building and irreplaceable.

UPVC ‘real’ sashes are an aesthetic improvement, with the profile and perceived depth to deceive the eye. Having lived in a range of rattled windowed vintage freezers, I completely understand being fed-up with double lined curtains and cling filming over the original sashes from October to March.

Oh, the period joys — sticking frames, the nibbling wildlife, rot, ivy pushing its claws through, flies breeding in the sash housing and popping out in droves to die on the sill —– been there.

A modern UPVC window offers a high resistance to wind and rain penetration, common to traditional sashes — even in poor shape. However, UPVC is maintenance free because once damaged it cannot be maintained. 

Wood sashes from as early as the 18th century can be repaired, even delivered back in some cases as double glazed units that slide like silk. 

Real wood windows win hands down for their low embodied energy, and, given appropriate detailing and finishing, they will need little attention for the first 7-10 years.

Steel paned windows common in the 1950s were truly freezing, with cold bridging, sharp peeling oil paint and warping opening sections. Happily, they are now gaining favour for restoration — rare, cherished survivors.

Michael Quirke of Conserve-A-Sash based in Kilgarvan, has worked on dozens of heritage projects including 250 sash windows in the South Presentation Convent in Cork. 

Clients generally come to him on foot of a conservation order to satisfy a grant application.

“We always encourage renovation over replacement,” he says.” 

Only 4% of the timber in the 14 month’s work at South Presentation demanded replacement”. 

You have to like a man still excited by the mysteries of the Golden Ratio of 1:1.6 rooted in a 300BC formula, crucial in 18th century architecture.

Vertically operating Yorkshire Light sliding sashes, some with two moving panes (double hung), others with one fixed panel, have been identified in plans and in Dutch masters’ paintings from over four centuries ago. 

Somewhere in the late 1600s between Holland and England, a window operated by counter-weights, braided cotton ropes and pulleys set in side housings (box-case) was developed between architects and carpenters, most likely for a great aristocrat’s home. 

In Victorian cottages the top pane was often shorter than the bottom, but the proportions were still lovely even with just four panes per window.

Today two six window panels (12 in all), with three panes across is the most commonly seen sash window in originals and pretenders.

UPVC sashes do not require box cases as they are light enough to operate without counterbalanced sash weights, springs and pulleys, and often open out and in to accommodate the fire regulations and to allow compression seals to work more effectively. 

Styled as sashes these casements can achieve energy efficiencies of up to 1.0Wm²K, require no painting and come in a choice of textured and tint finishes.

The price of restoring or replacing a sash window in hand-crafted timber will be expensive, out-sripping the parameters of quality glazing in other materials such as aluminium clad or even copper.

Many firms offer a survey service, offering choices from draught-proofing through restoration to full replacement. 

There will be cases, where restoration will be economically impossible, but the windows can be perfectly matched with a new bespoke window perfectly copied from the original joinery and detailing.

If the windows are in good condition but the room is perceived as cold, low-interference draught-proofing may be the answer.

Take a look at the excellent video by the team at Sash Windows in Sandyford in Dublin showing a large single glazed sash being draught, noise and rattle proofed with new cut grooves and brush panels at, under draught-exclusion.

Beyond this, repair work to elements of the frame (including the delicate sash horns, rails, beads and architraves), repairs to the boxes, together with the introduction of slim pane (7mm-12mm) double glazing, will utterly transform its heat performance, operation and looks.

Michael Quirke explains that the introduction of double glazing has other practical implications. ‘Slender Georgian windows made before 1780, under 1 ¾” deep cannot take standard double glazed panes, even the vacuum centred Amtico Spacia units.”

Early Georgian windows were made to be flush with the outer wall: “Replacing wood sash windows, compared to modern PVC windows is far less complicated, as there’s a frame inside the window, and generally no re-plastering required.

“Nonetheless, the job is skilled and highly labour intensive — and consequently expensive. I work in mortise and tenon not finger joints.

“Any window with double glazing will be twice the weight, so we replace the original cast iron weights with lead weights and rebalance the window.”

Plant-on (astragal) bars can be added to hide double glazed introduced to old windows, but again, this should be carefully done for any period building to ring true – potential savings, but still expensive. 

Windows that cannot accommodate boxes to the side, can be re-fitted with pre-tensioned springs for operation (ask about spiral balanced sliding sashes). 

Michael maintains that changing the original frames for new double glazed, hardwood frames is the most effective way of dramatically upgrading dilapidated single glazed windows with the least amount of disruption.

If your home is a protected structure, or you really just don’t want to go down the UPVC route, The Irish Georgian Society can give advice on the repair of important windows, and it’s worth getting in touch with the Conservation Officer of your local authority for help and references to suitable firms to carry out work on your old beauties. 

If you have a window of any date or design in a bedroom you know you couldn’t possibly get out of in the event of a fire, get advice and have it altered.

Michael Quirke of Conserve-A-Sash,

Period windows may be grant eligible under the Built Heritage Investment Scheme. Contact your local council for information.


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