Sash windows: repair or replace?
Rebecca Foster weighs up the pros and cons involved in restoring tired-looking sash windows versus installing new ones
ey ooze traditional charm, but what if these units are looking a bit tired? Rebecca Foster investigates the options
Your home’s fenestration plays an integral role in establishing its finished aesthetic. If you’re keen to upgrade sash windows as part of a renovation scheme, careful thought is required when it comes to deciding whether it’s better to repair existing units or replace them entirely. In addition to preserving – or even enhancing – the appearance of your property, energy efficiency should be a top priority when making this choice. Both routes represent a significant investment, so it’s vital to do your homework, avoiding any snap decisions that could negatively influence the value of your house. So let’s take a closer look at the pros and cons of each route to help you decide which one is best for your project.
Restoring the originals
Sash windows play an enormous role in establishing the authentic appeal of traditional homes. In fact, they’re likely to be one of the chief design features that attracted you to the house in the first place. “Maintaining these units is part and parcel of owning a period property and regular upkeep preserves their charm and adds value to the dwelling,” says Chris Herrington, commercial business development manager at Ventrolla. “As such, it’d be a shame to rip them out and replace them with substandard alternatives.”
While flaking paint, rotting wood and even draughts may lead you to believe your fenestration is beyond repair, this might not be the case. Many companies offer specialist services for the restoration of sash windows, so it’s worth bringing an expert in for a survey so you can determine whether refurbishment is possible. “By renovating, you can tackle main issues like draughts and rot whilst maintaining the look and feel of your home,” says Chris.
However, if you do go down the refurbishment route, it’s possible that additional issues will be uncovered once work has started – which may result in extra time and cost to your project. “This is especially the case where the unit has been painted over multiple times and so is fixed shut. It’s difficult to identify the state of the timber beneath when the initial survey is carried out,” says Chris. So, depending on the extent of the repairs required and status of the house, you’ll need to assess whether it’s more cost effective to rip out the existing units and install new ones.
One common issue is spongy, rotten wood in the frame. This can be dug out and routed back to sound timber.
New sections, moulded to match the originals, can then be spliced into the unit, sealed, primed and decorated. As they will take the brunt of the British weather, the sill and bottom sash are the most vulnerable areas and are therefore more likely to require repair work.
Overpainting is a frequent issue with sash windows, with layers building up over the years to cause stiffness in the sliding mechanism. Sanding the frames down and redecorating can help to resolve this. It’s best to
avoid using impermeable modern finishes as they may trap moisture inside the unit and lead to damp.
Issues with the window hardware may also need to be addressed. “For example, the cords could have rotted and lead weights may have fallen to the bottom of the sash box,” says Steve Brattle, divisional sales manager at Anglian Home Improvements. Such issues can easily be dealt with by an experienced specialist.
Draughts are another frequent issue with older sash windows and can lead to cold spots throughout a house. “We install a draught-proofing system in and around the sashes, closing any gaps while still allowing the leafs to pass by each other,” says Chris. “This usually provides the level of thermal efficiency people need. Slimline double glazing can also be fitted for further energy savings.”
If you do decide to go down the route of repairing your windows, do your homework when it comes to tracking down a professional to carry out the works. “Any reputable window company will be able to provide you with examples of previous work and customer references,” says Chris.
Replacing existing units
Determining whether it’s better to repair your sash units or switch them out for new ones can be tricky. If significant refurbishment is needed, the tipping point usually comes when it’s more cost-effective to replace old fenestration with modern alternatives. “We can save many windows that look beyond repair, but the cost involved may not be worth it,” says Ventrolla’s Chris. Typically, substantial restoration is only really of value on heritage units. It’s unlikely to be worth saving softwood units dating back to the 1980s or 1990s. Plus, if your fenestration can’t be repaired, new versions could add value to your home. This is also a chance to boost your property’s thermal efficiency by installing the latest high quality designs.
Before taking the plunge, bear in mind that installing new windows throughout the house qualifies as major building work. “There will be disturbance to the stone/ brickwork, plasterwork and internal decoration,” says Chris. “Some period homes have panelling and shutters, too, which would be disrupted when installing a replacement.”
Fitting the wrong design could damage the exterior appearance of your house. When it comes to identifying the best units for you, take the property’s age, location and materials palette into account. Your goal is to select windows that enhance character rather than detracting from it, so reach out to the local planning department or even estate agents in your area for advice. Another good idea is to have a look at what your neighbours have done, taking note of what does and doesn’t look right.
There’s a plethora of factory-made sash windows out there, designed to match specific vernacular styles, so take your time to investigate potential suppliers. Custommade joinery solutions are also readily available if bespoke units are a better fit for your project. When replacing existing fenestration, it’s worth getting your supplier to carry out their own survey. That way if they don’t fit when they’re delivered to site, the fault lies with the company and not you. Similarly, opting to go with a supply and install service can pay dividends in the long term.
Selecting the right frame material is likely to be one of the biggest decisions you make when specifying new
units. For authentic period charm, few materials can match the innate warmth and character of timber. Depending on your budget, softwood and hardwood versions are available, with the latter being at the higher end in terms of price. There’s also plenty of choice when it comes to finishes, whether you prefer a painted or stained effect. Wood is a natural insulator, so timber units are an excellent choice if thermal efficiency is one of your project priorities. Expect well-maintained units to last for 60+ years.
PVCU is the other contender when it comes to replacing sash windows. The development of frames in this material has come a long way over the last 10 years. “Modern units are very realistic, with timber grain finishes, built-in horns and dimensions to match originals,” says Steve.
High quality versions feature a multi-chambered design to remove the risk of warping. Profiles are also slimmer than they used to be. Despite this, PVCU products can’t quite match the slender form that timber offers, so wood often remains the best choice for heritage properties. PVCU windows will offer a lifespan of approximately 35 years and will require little maintenance.
“Prices for PVCU start at around £1,200 per window (800mm x 1,500mm) and will increase with decorative options such as cottage bars, sash horns and colour variants. Timber is around 10-15% more expensive,” says Steve from Anglian Home Improvements. According to him, one of the main hidden costs when replacing with PVCU units is the removal of sash boxes and rebuilding the wall area created by the void. “This can add up to £400 per window. Some companies may cut this out by fitting the new models and leaving the existing structure in situ. This is not good practice, as it looks unattractive and can lead to further problems as the old timber boxes decay.”