Replacing timber box sash windows with PVC

Replacing timber sliding sash windows is often an overlooked yet significant aspect of a residential renovation project, and we always aim to work to development budgets from the outset wherever possible, offering three designs of Vertical Sliding Window in PVC, the KAT Classic, KAT Elegance and KAT Mayfair.

PVC box sash windows replace timber

Original timber box sash windows have been replaced with low maintenance PVC

Benefits of PVC Vertical Sliding Windows over Timber

Traditional timber box sash windows remain a popular, and sometimes necessary choice for residential renovation projects, but PVC is evolving at a rapid pace and is still the preferred alternative, providing stunning period-style vertical sliding windows that can also pass on cost-savings to the homeowner.

Bespoke sliding sash windows

The homeowner chose to have Georgian bars in the top sash only

What to consider when replacing timber box sash windows

Cost difference between Timber and PVC – timber will always be considerably more expensive. This typically affects the decision-making between products, especially for larger projects with ten windows upward.  Customers often feed back how genuinely authentic the premium ranges look, such as KAT Mayfair with their wood-effect surface, through-horns and period-style fittings.

PVC Sliding Sash Windows

Showing run-through horns

Child restictors fitted to box sash windows

Authentic window furniture


Sliding sash window with timber look

KAT’s premium range Sliding Sash window with wood-grain effect

Maintenance of Timber box sash windows – it is no secret that timber windows require much more TLC than PVC, with at least an annual coat of varnish or paint required to protect from weathering that can cause rot. PVC VS windows are manufactured to be low maintenance, because of their material and the tilt-in sashes to enable cleaning from indoors. Download a brochure

Tilt option for box sash windows

VS with tilt option for easy cleaning of outside of windows

10 Year Window Guarantee – PVC windows (from KAT) are guaranteed for 10 years as with every other product in our PVC and aluminium portfolio. With due diligent repair work, timber windows can last many years, but most households are short of time and do prefer the easy maintenance and operation of PVC. Request a quote

Thermal performance of Sliding Sash Windows – traditional timber box sash windows can rattle in the wind and be draughty.  Whilst this does add to their charm, KAT’s PVC timber alternatives have excellent weathering and thermal qualities that will pass on energy savings too. Visit KAT’s webpage to discover the features of PVC Sliding Sash Windows.

What is the delivery time for bespoke box sash windows?

Lead time – KAT’s PVC windows are made to the highest quality, from order to delivery in two to three weeks and are delivered in KAT’s own fleet of vehicles. Timber can take up to eight weeks to manufacture.

Georgian bars on VS windows

PVC Sliding Sash Windows with Georgian bars

Window with arched head

Vertical Sliding window with arched head

KAT manufacture PVC Vertical Sliding Windows in a wide range of colours, to bespoke sizes, all glazed with argon filled double glazed units to keep your home warm. If you are looking for a shaped frame with an arched head, we can manufacture these too. For more information, download a brochure, contact the Customer Services Team on 01625 439666 or send an email to [email protected]

KAT supply doors, windows and roof glazing to the trade and can put you in touch with a Design Partner near you, who will then provide you with a quote to supply and fit your new doors and windows.