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Draught Proofing – Us & Them

In cases where a carpenter is called to look at a stiff window, they will sometimes to decide to plane (shave) the sides of the sash in order to make the sash move smoothly within it’s opening. So long as the true culprit is the sash itself, there’s nothing wrong with this; however, we often find that the real culprit is the over application of gloss paints over the years that cause the window to become stiff.
This is why we’ve developed a much fuller and more comprehensive draught proofing service; to ensure that the work we do actually fixes the customer’s problem and doesn’t simply fix it for today while creating another problem further down the road. Our draught proofing services are essentially an economical restoration service – with limited repainting we can save a lot time on site, so we can provide you with the bare bones service that you need to get your windows to a good level of functionality.
So how do we compare to other companies out there, and what makes us special?

Core’s Draught Proofing Services:

  • Full dismantling of your sash window.
  • Add a timber packer with glue, resin and pins. We do not add packers to the bottom rail, as it is too susceptible to water opening up joints in the future.
  • Adjust the packers, such that the window is neither too hard to open, nor too loose that it will compromise the draught proofing and let in more exterior noise. In some cases, it is reasonable for our fitter not to have the window open fully as you may intentionally compromise the integrity of the draught proofing. We would generally tell our men that a 70% opening operation is acceptable. You can discuss this with your fitter if you have an issue with an off-level box.
  • Change all the cords to waxed cotton with a nylon core. All cords are covered in masking tape to keep them clean for the duration of the works.
Draught Proofing Services - Materials
White Waxed Cotton Sash Cord
  • Balance the windows correctly; adding or removing weights as necessary.  Additional weights will need to be charged.
  • All the staff and parting beads are removed and replaced with new ones, complete with the Aquatex A10 weather seal. The Aquatex seal is washable and insulates sound and heat far better than the more common felt brush. Felt brushes also tend to attract dirt and grime which makes keeping your window clean that much harder.
Draught Proofing Materials
Parting Bead (left) and Staff Bead (right) Complete with Aquatex A10 Weatherseal
  • Prime areas of timber which have been planed / shaved by in order to protect the timber.
  • Groove the top/ bottom and mid rail to carry the Aquatex A10 seal.
Draught proofing materials
The Aquatex A10 Weatherseal
    • Touch up in customer supplied paint or our standard RAL: 9016 paint.
    • Adjust the locks on the sashes.


We can carry out this service in conjunction with repairs, new sashes, new hardwood sills, timber splice repairs and new ironmongery at an additional cost. These services entitle you to a 2 year guarantee.

Most other companies don’t:

  • Add packers to the sides and top of the sashes.
  • Protect the sash cords with masking tape, resulting in dirty cords on completion.
  • Remove the sash from the existing cords. This saves time as they don’t have to groove the top rail. Instead, they add on an additional piece of timber (parting bead) to the top of the box. You would only do this if the box was designed to accommodate this extra parting bead, which is a relative new design feature on sash windows.
  • Touch up the paintwork.