Pre-Engineered Windows
Factory-precise, so the site work stays simple.
Traditional windows are often built through batch production, with partial factory work and partial site assembly — leaving final quality dependent on the skill of whoever is on site that day. TOSTEM takes a different approach, borrowed from pre-engineered construction: the window is designed and fabricated at the factory, and only the assembly of finished components happens on site.
Because roughly 90% of the work happens in a controlled factory environment, there's no room for quality to drift between what's tested and what's actually installed — the performance you see in TOSTEM's lab is the performance you get in your home. Every unit arrives with hardware pre-fitted at the factory, so site work is reduced to precise, tool-free assembly rather than on-site fabrication.
This is delivered as what TOSTEM calls a 'window-in-a-box' — sash and frame packed separately, labelled, and dispatched directly to site, keeping transit damage and installation error to a minimum.
What this looks like on site.
Precision manufactured at the factory, before it ever reaches site.
Hardware pre-fitted, sealed, and tested before dispatch.
A tool-free, factory-precise fit on every installation.
How we deliver it.
Factory-fabricated, not site-built
Every window is manufactured to spec at TOSTEM's facility, with only final assembly happening on site.
No quality dilution
With ~90% of the work done under controlled factory conditions, tested performance and actual performance stay identical.
Pre-fitted hardware
All hardware arrives pre-fitted from the factory, minimising the time and skill required on site.
Window-in-a-box delivery
Sash and frame are packed in separate, labelled boxes, reducing transit damage and simplifying site logistics.