Sash Window Brush Pile & How to Use It

Brush pile is a form of draught-proofing and significantly enhances the fit and performance of traditional sash windows.

Brush pile also solves some of the biggest problems with sash windows which are the infamous sash window rattle on a windy day, dust and dirt ingress – a problem in town locations – and draughts that keep the interior cold even if the heating is on high. Brush pile also helps blot out external noise, promotes smooth opening and closing of the sashes, and will help protect the householder’s energy bills. So, if your sash windows don’t have it then it seriously could be time for an upgrade.

Energy Efficiency and a Cosy Home

Draught-proofing sash windows attracts a reduced VAT rate of 5% because of its impact on energy consumption. You’ll immediately feel a difference in the comfort levels of your home and then see a difference when the utility bills arrive. You may even be able to turn down the thermostat now that your precious heat is not leaving the building via the gaps around the windows.

Don’t Sash Windows need a Gap in order to Move?

Sash windows do require a 3mm gap between the sash and frame in order to function and travel smoothly. Fast forward a few years and add a few paint layers, some twisting and warping of the wood throughout the seasons and this tolerance may be more like 5mm in places where the window has been sticking. It’s the equivalent of leaving your lower sash open nearly a quarter of an inch!

Brush Pile vs. Foam Strips

Foam strips are an alternative option to brush pile but don’t last as long. Foam has much more memory than brush pile and so doesn’t return to its original density as easily. If the foam is damp and then compressed, it doesn’t spring back as readily and it perishes much more quickly. It’s also not so versatile on old windows with varying gaps, that’s most sash windows in most period homes!

How does Brush Pile work?

Brush pile is inserted into all the different edges of the sash window to make a complete seal. The top of the sash, the meeting rails, the lower rail on the bottom sash, the parting bead, and the staff bead all have brush pile draught seals installed.

A router and straight flute cutter are used to create a neat, accurate groove. This provides a stable base to secure the pile carrier with a little silicone-based adhesive. A brush pile is then inserted into the channel. This two-tier system has the added benefit that if a draught seal is damaged or no longer effective, it is a quick and easy job to replace it.

We always use a low-drag brush pile which reduces friction so the sash will continue to travel smoothly, making it easy to open and close. Low-drag pile results in far less scuffing to paintwork. All brush pile should be guaranteed for a minimum of five years. Brush pile can be installed when sash windows are being repaired or refurbished.

We repair and restore old sash windows for traditional houses and period homes. We also manufacture new replacement sash windows with brush pile draughtproofing as standard for old houses and for contemporary homes and self-builds. Our joinery can design windows in any shape, size, or style with an infinite range of colour choices. Not only do our windows offer superior draught-proofing but optimal thermal regulation, security, and acoustic control come as standard.

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