Sash Window Repair and Renovation

Sash Window Repair and Renovation

Although our work is mainly workshop based, focusing on fitted furniture and doors, we still like to get involved in window repairs and restoration. There is a certain satisfaction in bringing an old and decrepit window back to life.

Prior to setting up Waterhall Joinery over 10 years ago, I was the Operations Manager at a specialist window repair and refurbishment firm. Martyn also worked there for several years, as too did Mat and John.  So in all we have an accumulated experience running into decades.


Listed Building Window Repairs

Sash window in need of repair


At the start of last summer I was asked to survey this rather sorry looking window in a Listed building.

The owner wasn’t sure if they needed a new window,or whether sash window repair and renovation would be more appropriate.

On initial inspection:

  • The sill was no longer visible as it was covered in concrete. This is common, in years past when the sill has become rotten, rather than cutting it out and replacing it, people used to cover it in filler or concrete. Inside this casing the sill with its trapped moisture continues to rot.
  • The outer linings (vertical to the left and right) had timber nailed to their base. This suggested that’s the linings would be rotten where they met the sill. As I knew the sill was already in a poor state, this was a given.
  • The puckering to the bottom rail (horizontal in the lower sash) suggested extensive rot probably going all the way through.
  • The bottom sash was not original to the window. The width was slightly different and the glazing moldings did not match those in the top sash or other windows in the property.
  • There was also some rot to the meeting rail (horizontal at bottom of top sash) in the top sash.


Sash Window Repair and Renovation Process

The first job was to make a new bottom sash with styles and rails the same dimensions as the original upper sash.  We also needed to match the glazing molding and glazing rebate size.

Then we cut out the areas of rot in the bottom of the outer linings and gradually broke up the lump of concrete acting as a sill.  Indeed as we suspected underneath this casing was the remnants of the old sill, still very sodden.

Old rotten window frame in need of repair

We then installed a new hardwood sill and pine splices to the pulley styles and outer linings. These were bonded to each other and to the original timbers using the Repair Care Dry Flex resin system.

This helps as it retains flexibility so that as the timbers move with the change in season, these joints stay bonded and don’t open up.

Wooden repairs to old rotten sash window


The bottom sash was fixed in place as unusually this was a non operating sash and had no pulleys.

The top sash was rehung on new waxed cotton sash cord and the window was reassembled with new staff bead and brass catch.

During the process we had painted the box/frame and sashes whilst the window was apart as this was much easier.

One final coat of paint once reassembled and the window was finished. Very satisfying to be able to compare the before and after pictures. This sash window is now ready to live on for many more years.

Window restored completed


Old rotten wooden windows do not always need replacing.

It may be that they only require a professional window repair or restoration, which is equally as good.

Talk to the professionals and find out if that’s the case.  Restoring original windows helps to maintain the buildings character and history.  Once completed, it can provide you with a new solid window, that can last for many more years.

Contact Waterhall Joinery for a free quotation or advice on your window repairs.


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