- Unlike casement windows, they are impossible to seal completely from the outside world: for them to operate they must be free to slide – this requires a track which is formed by various beads and rebates.
- Sash windows are therefore naturally ‘trickle ventilated’. Furthermore, greater ventilation is available in the centre of the sashes: by lifting the lower sash a fraction, a passage of air is free to enter the room without actually opening the window – this is achievable by the addition of an up-stand below the bottom staff bead called a ventilationFurther addition of trickle ventilation devices is, in our opinion, unnecessary.
- Original sash windows were prone to draughts and rattle; they were also poor at deadening the noise of the street outside.
- Draught seals have been developed specifically for sliding windows and are included, to a greater or lesser extent, by all modern manufacturers of this window type.
So, we now have the technology to at least partially retain the healthy benefits of trickle ventilation whilst simultaneously getting rid of draughts, rattles and whilst dramatically reducing dust ingress and street noise.
- We specify a triple-layer draught proofing system as standard to each window we produce – this acts between the sashes, the sashes and the frame and has a further cushioning seal between the lower sash and cill to negate sash movement caused by the vibration of passing vehicles or during stormy weather.
- Not many other producers go to the lengths we do to make your windows weather-tight.
- Unlike some manufacturers we discreetly place the weather-stripping into the sashes themselves wherever possible – this allows future generations of carpenters the ability to buy replacement beads ‘off the shelf’, avoiding the necessity to have them made specially.
It would be tempting to skimp on draught-proofing your new windows, after all, the system is not cheap and the many grooves required to hold the lengths in place all take time to machine, however, we feel that without this level of protection, you would notice the difference.