For builders and site managers
Preparing Openings for Glazing
What we need, and when
Short answer
A base depth of 210mm with a full cavity infill, side cavities in hard insulation or timber. The opening must be ready 2 weeks before installation, confirmed by photographs. If it is not ready when the fitters arrive, a further installation fee applies.
The base
A depth of 210mm, with a full cavity infill. Side cavities are infilled with hard insulation or timber. Check the detail against your own building control officer before you pour, because the responsibility for what is built sits on your side of the line.
If you would rather we prepared it, we can. That adds £850 + VAT to the order value.
Timing, and why two weeks
The opening has to be complete 2 weeks before installation, and we ask for photographs to confirm it. That is not administrative caution. Units are made to the surveyed size, production runs 6 to 8 weeks, and glass cut to a size that has since moved cannot be adjusted on site.
Tell us 1 to 2 weeks before the openings are ready and we will book the survey. Our Project Manager and Designer attend together, so the measurement and the design decision happen in the same visit rather than in two.
If we arrive to an opening that is not ready, a further installation fee is charged, and if the units have to come back to us storage runs at £350 per week. Neither is a penalty anybody wants to raise; both exist because a van, a crew and a crane booked for a Tuesday cannot be un-booked on the Monday.
Who carries the size
Where we survey, we carry the size. Where we work from your figures, sizes Apex did not measure remain the customer’s responsibility, and floor level calculations sit with the customer or their builder.
It is worth being blunt about this because it is the single most common source of dispute in glazing, and it is nearly always discovered on the day. If your floor levels are still theoretical when we survey, say so and we will note it on the drawings rather than assume the slab is final.
Sign-off
You get CAD drawings covering opening configurations, sill placements, glass options, colours and handle choices. Production starts only after the drawings are signed off, so a change at drawing stage costs nothing and the same change three weeks later costs a unit.
Once the drawings are signed, the sizes on them are the sizes we make.
Installation day
Site access must be free of scaffolding and other obstructions. If our team cannot get to the opening we reserve the right to recharge the installation balance, which again is about a crew that cannot be re-deployed at short notice.
The product balance is due 7 days before installation. To move or cancel a fit we need 3 working days notice.
Common questions
What base depth do you need?
210mm, with a full cavity infill and side cavities infilled with hard insulation or timber. Confirm the build-up with your building control officer.
How far in advance does the opening need to be finished?
2 weeks before installation, confirmed by photographs.
Can Apex prepare the base?
Yes. It adds £850 + VAT to the order value.
What happens if the opening is not ready on the day?
A further installation fee is charged, and if the units return to us, storage applies at £350 per week.
Who is responsible if a size is wrong?
Where we survey, we are. Where we work from figures supplied to us, sizes Apex did not measure remain the customer’s responsibility.
How long is production?
6 to 8 weeks from sign-off. Everything is manufactured in-house.