The Art of Sash Window Draught Sealing

Most people who opt for a house with sliding sash windows are enthusiasts for the feature, you must be really as sash windows are not something you can just ignore, a bit like many aspects of a period or traditional property.

Sash windows can strike fear into the hearts of some people as they do have a bit of a reputation for being draughty and that means cold rooms no matter how high you crank up the heating and that distinctive sash window rattle! However, good care and maintenance plus new modern materials mean you don’t have to just put up with noisy, draughty windows.

Why are Sash Windows Draughty?

Sliding sash windows are designed to move up and down so there has to be some play in the way the window sits in the frame but there are actually lots of other windows why sash windows let in draughts.

  • The windows have not been properly installed
  • The locks are failing or broken, this means they don’t sit snugly when closed. You should not feel any fresh air coming in around the window edges if the locks are working properly
  • Old or damaged window seals are a problem with uPVC sash windows. The seals weaken over time just through wear and tear although a build-up of mould can also contribute to the problem. The seals can also shrink on uPVC sash windows, leaving a gap between the sash and the glazing
  • The windows don’t close properly and don’t sit squarely within the frame. Every edge and corner should line up with the other so there are no gaps
  • Timber sash windows are more susceptible to damp, wood rot and wood worm so the structure of the window will change if it’s not properly looked after – this then affects the way it sits in the frame

Sash windows ‘settle’ over time, particularly in period properties which may have walls made of non-standard materials that cause some degree of movement like clay lump or wattle and daub.

Draught Sealing Sash Windows

The correct way to draught seal sash windows depends on two factors, the type of windows you have and what is causing the draughts. It’s always best to get the windows assessed by window professionals – you may be able to make good yourself but you could just make matters worse if the problem is more deep rooted and/or you choose the wrong remedy.

Simple cracks around the window can be filled with silicone but this doesn’t work for larger gaps, but these can be blocked with rubber. Weather stripping products are available from all DIY stores and hardware shops, but these can require quite expert fitting otherwise they won’t work and look awful. Glue on seals don’t always sit well for sash windows because of the constant movement of the sashes; they tend to wear away due to friction and the uneven surface commonly created by numerous layers of paint.

Professional draught sealing costs more than the DIY alternative but experts have the advantage of knowing the right materials to use and where to use them.

New draught sealing products also minimise the aesthetic impact on the window – many are invisible and best of all, repair services which include draught sealing attract a reduced VAT rate of 5% for residential properties.

We use uPVC carriers with a brush seal and these work well on the biggest challenge of all which is very old Grade I and II listed houses. The brush is low friction so doesn’t impede the movement of the sashes plus they are almost invisible when fitted so everyone’s happy from the homeowner to the listings officer.

Parting beads are another option. These are vertical seals which fit between the upper and lower sashes and create a channel for the panels to slide past each other. Some beads are manufactured with a weatherpile or brush. We don’t use plastic parting beads as they fade and discolour, and this highlights them against the timber frame.

The Benefits of Draught Sealing Sash Windows

There’s lots of information online from organisations like the Energy Trust about the benefits of managing draughts. Every house needs ventilation, but draughts are uncontrolled regulation, so this impacts not only your heating bills but the environment. Homes with proper draught sealing are warmer and will allow you to turn down the thermostat. Correctly sealed sash windows will also reduce noise from outside, essential if you have an old house in a busy town location or on the roadside.

We restore and refurbish sash windows for all types of homes and commercial properties from the ancient and historic through to more recent builds that are just not performing properly. We work onsite and survey thoroughly before recommending products which will work for your home. We also bespoke manufacture new timber sash windows in any specification, size and style with a limitless choice of paint colours. All our windows offer the very best thermal regulation, noise reduction, security and draught sealing with our unique partnership of traditional craftsmanship and modern materials.

Contact us here to find out more about our sash window repair and restoration service and bespoke sash window design.