Sash Window Repair & Restoration

It’s not uncommon for sash windows, their cills and sometimes even their box frames to require restoration. This is especially likely when left unpainted for a sustained period and where water has become trapped around unprotected timber.

When a sash or cill has been compromised, we’ll offer advice on whether to repair or replace, although the final decision always rests with the customer. For sash repairs, which are typically located around the lower tenon joint and bottom rail, we will splice in a new section of Accoya using a two-part, epoxy, adhesive/filler or, where required, replace the entire rail (taking care to match the profile).

Accoya Affiliate mark Approved manufacturer WHITE ON GREEN RGB

Original Sash Window Solutions completed Accoya manufacturer training in Jan 2020.
Click for more

Accoya is the world’s best known, super-durable wood. It starts life as the Radiata pine in the sustainable and scrupulously maintained forests of New Zealand, before undergoing a process of acetylation in the Netherlands.

One of the great benefits of Accoya is its stability. It doesn’t swell, twist nor warp and it simply refuses to rot. The acetylation process stabilises it superbly. This makes it ideal for bonding and splicing into existing woodwork which itself will already have substantially stabilised over time. Lack of movement on both substrates makes for an enduring bond and ensures a repaired sash will always run smoothly.

Accoya’s expensive (around twice the price of most commonly-used, unsustainable hardwoods). It is even dearer than oak. However, the rot-resistant and durable properties of Accoya make it the ideal choice for delicate sash window repairs, where the greatest cost remains the labour and where stability of substrate is key to the enduring performance of any repair.

accoya sash windows

With cills it is almost always best to replace the entire cill once the rot becomes apparent on the surface, unless the rot is isolated and central. This is a specialist job which should be done using high quality timber with the correct profile. The bottom sections on both sides of the box should always be replaced at the same time as the cill to ensure that no end grain is left exposed and the strength of the corner joints is restored.

We use Accoya or Sapele in our joinery repairs, which are covered by our 5 year guarantee.