Steel Windows Replaced by Composite Wood-Alu in North Oxfordshire

Revisiting an older project – we can’t believe this was 3 years ago! The pure steel windows in this building had clearly been there as long as the house itself because they were fixed into the stonework with thick 6 inch steel poles…

The house was effectively built around the windows, so it was a significant job to safely extract some of the lowest performing windows we’d ever come across. The timber front door and double door set on the front elevation were in relatively good condition, so we supported the customer in their choice to leave them in place – allowing us to focus on the main body of steel-framed issues.

Replacing an old steel frame with a new steel frame can often be a waste of time and money, because metal is still just as solid and still conducts heat the same way it did decades ago. Therefore, that “upgrade” would run the risk of being purely visual.

Since the structure of the building allowed it, a timber-based solution is a far better bet. Add a less busy decorative bar arrangement and the protective aluminium layer on the outside, and we create a modern high performance window with minimal maintenance, still with a traditional appearance.

An STM Tinium window was the order of the day here. Made in Denmark and DVV certified, this is one of the few composite windows where the aluminium face is not just plastic-clipped onto the timber frame. A proper inch thick polyamide break runs all the way around the outer frame, meaning rainwater can never get stuck up against the timber – the risk of rotting from inside out is vastly reduced.

Buildings naturally have a bit of movement over time – naturally expanding and contracting throughout the year, and not always settling back down exactly where started… Due to this, replacing bay windows of this age often presents an interesting set of problems to overcome. You can’t assume that two angles clearly meant to be 45 degrees are still 45 degrees decades later. And creating a post a few degrees out can push the other end of the window massively out of place at the other end.

Luckily, we’re in a world where digital angle finders exist, and Danish factories are more than happy to create very specific angles on their aluminium-clad timber cornerposts.

And finally, a convenient before and after photo comparison showing how much has changed! The home still has a classical look, with a softer wooden frame appearance, a more Cotswold-friendly RAL 7032 Pebble Grey colour and a conversion to a less busy single glazing bar design.