Customers choose the profile and glass carefully but rarely ask about installation. Yet that's where it's usually decided whether a window lasts twenty years.

A badly installed window is easy to spot, but only after the first winter. Damp around the frame, black patches in the corners of the reveals, draughts that shouldn't exist, a sash that doesn't close properly. None of that is a fault in the profile. It all comes from the installation.

What good installation looks like

Measuring on site

A window is made so that a proper gap, the joint, remains between it and the wall. Too small and there's no room for insulation; too large and it's hard to fill well. That's why we always measure ourselves, on site.

Protecting the room and removing the old windows

We cover floors and furniture with sheeting and take out the old windows carefully, to damage the reveals as little as possible.

Positioning and fixing

The window is set level and plumb and fixed into the wall with anchors or frame screws. Foam isn't a fixing, it insulates and fills the joint, but it must never be the only thing holding the window.

The foam must be protected

Polyurethane foam breaks down within a few years in sun and damp. So it needs protecting on the outside, with tapes, sealant or the façade finish, and on the inside, indoor moisture must be kept out of the joint. For new builds and energy renovations we recommend so-called RAL installation, with vapour-tight tapes inside and vapour-permeable ones outside.

Adjustment and finishing

Finally, the hardware is adjusted so the sashes close evenly and the seals meet along their full length. We take the old windows away and leave the place tidy.

How long does it take?

It depends on the number and size of windows. A flat with several windows is often done in a single working day. Larger buildings take longer, as they should. Rushed installation usually gets paid for later.

What to ask an installer

  • Who measures and who installs, the same team or a subcontractor?
  • What is the window fixed to the wall with?
  • How is the foam protected on the outside?
  • Is finishing the reveals included?