Window sash repairs | Sash Window Repair or Replace?

Here we look at the pro’s and con’s of Window sash repairs | Sash Window Repair or Replace?

The decision whether to retain your existing period windows and have them repaired and upgraded, or take them out completely and be replaced by new timber or uPVC windows, is complicated. There are many factors to consider including cost, disruption, aesthetics and the value of your property.

Circumstances to take a decision:

Of course there are circumstances where the decision is taken out of our hands such as when the property is listed. Where listing applies it is essential to take advice from your local Planning and Conservation Officer. Also if you are in a Conservation Area it is always worth checking if an Article 4 Directive applies to your property. This Directive specifically protects the main elevations of the property to ensure they are not changed visually from the original.

Falling foul of planning regulations is definitely not something we would advise as it can result in very expensive legal actions being taken and the work to re-instate the original windows.

Assuming there are no restrictions in place let’s look at the pro’s and con’s of replacing versus repairing.

The starting point is your personal view towards conservation. Ask yourself how you would feel about seeing 100 year old joinery sitting in a skip! If this is uncomfortable then go for restoration.

Cost of Window sash repairs:

It is almost certainly going to be more expensive to replace existing timber windows with new timber. Bespoke joinery is expensive. Replacing with uPVC will probably be cheaper in the short term but repair by an experienced carpenter or window specialist will usually be a lower cost


Complete replacement is very disruptive to internal decoration and the decorative internal mouldings will almost certainly be lost. Repair will be messy in the short term but the important architectural features will be retained and re-decoration limited to a touch-up

Aesthetics of Window sash repairs:

There is nothing that can replicate the look of a period window. They ‘suit’ the property. Repair will retain the look, anything else and it will be changed forever.

Value of Window sash repairs:

There is a definite move in property values toward period features. Buyers have got bored with the same ‘me-too’ look of many properties. Estate agents will value a property with original stand-out features higher than one that has been ‘modernised’

Double Glazing:

Perhaps the biggest single reason to change windows is from the existing single glazed to double glazed. Glass technology has moved on so much over recent years that it is now possible to retro-glaze most period windows using very slim sealed units, in particular Pilkington’s Spacia Vacuum Glazing product which is only 6.5mm thick.

Do be cautious of using very slim sealed units that rely on dessicant to control the moisture between the glass panes. The ‘failure’ rate is proving to be very high with some not even lasting 5 years before they begin to mist up. Hope this article helped you in making a decision regarding window sash repairs.

Read More: Thermal efficient windows | A hybrid approach to improving efficiency, Condensation problems with Glass | What is Vacuum Double Glazing?

For more information regarding these topics, our discounts on products, and promotions you can visit our Facebook page.