Sash And Casement Windows

Double-glazing companies want to sell you their product, each espousing that theirs is the best and that their uPVC, fake-wood windows will suit your red sandstone tenement flat or B-listed Scottish Baronial home perfectly! They don’t understand (or care) the effect it will have on your health or the health and the value of your property, let alone the loss of the original, high quality (if not currently good condition) windows and doors.

Everything can be repaired, it just depends on your budget and the importance you place on traditional features and your concept of ‘embodied energy‘. Having recently returned from a timber window repair and maintenance course presented by the clerk of works and master joiner at Balmoral Castle, I consider myself suitably refreshed.

Building Control, via legislation, requires heat-loss minimised (measured by the rate at which heat passes through a material [U-value]), which makes perfect sense – when looking from a purely energy consumption point of view but it doesn’t take into account the performance of the building as a structure or as a healthy living environment. The same legislation demands a certain amount of air via ‘trickle vents’ cut into the tight-fit, high-performance windows, but most people (human nature intervenes again) keep them closed anyway. This trickle vent is to allow fresh air to enter the building – fresh air that was prevented from entering through the tight-fit windows! Go figure!

We need oxygenated air to breathe and require a certain amount of fresh air (air changes) from the outside and to allow exhausted air (breath) out. Limiting the amount of air changes by tight-fitting windows and blocked fire-places increases the amount and severity of respiratory diseases and increases dampness which is evident at wall/ceiling junctions, corners and behind furniture against external walls and to windows. The fact that the corner of an external wall (floor or ceiling) has black mould is simply because it is 1. colder on an outside wall and 2. a corner has less movement of air around it and, therefore, can create a ‘micro-climate’ in that area. It does not necessarily mean that there is moisture penetration!

Old buildings NEED to be understood.

Original timber sash and casement windows allow air infiltration and, together with an open flue, are healthier for the house and its occupants. Why do we now need bathroom extraction and cooker extraction? Not only because of the increase in moisture but because that moisture cannot escape as it used to be able to.

I’m not advocating for a return of rickets and ring-worm, just for a better understanding of our built environment and for us not to treat all forms of construction the same. Why have buildings managed to last for so long and are now decaying faster with the application and installation of modern systems?