Installation · 3 min read
What Happens During a Window and Door Survey
The technical survey is where an approximate quotation becomes a fixed, accurate order. Here is what a surveyor actually checks, and why.
When to Order Windows for a Self-Build
Order too early and specifications change under you. Order too late and the build stalls waiting for glazing. Here is how to time it correctly.
6 min read
Written by Windows in the Lakes · A trading name of Home Glazing Ltd
As a rule of thumb, place your window and door order once the design is fixed and the structural opening sizes are confirmed on the working drawings — typically around the point the roof structure is being designed, and well before wall-plate level is reached on site. That timing gives a manufacturer enough lead time to have frames ready for the watertight stage without holding up the build.
Self-build programmes live or die on sequencing, and glazing is one of the few packages with a genuine lead time that cannot be compressed by throwing more people at it. Order too soon, before the design has settled, and you risk paying for changes or ordering frames that no longer fit once the architect revises a room. Order too late and the single biggest cause of self-build delay — waiting for windows to arrive before the roof can be made watertight — lands squarely on your programme.
This guide sets out a practical timeline, worked backwards from the date you want the building watertight, so you can slot glazing into the wider build programme with confidence rather than guesswork.
Working backwards from your watertight date
The most reliable way to time an order is to start with the date you need the building watertight — usually shortly after the roof structure and covering are complete — and count backwards through survey, manufacture and delivery.
- 01Fix the watertight dateAgree with your builder or project manager the target date for the roof to be on and the building sealed against weather.
- 02Subtract installation timeAllow one to two weeks for windows and doors to be fitted across a typical self-build, depending on scale and how many openings there are.
- 03Subtract manufacture lead timeAdd the typical lead time for your chosen product — commonly six to ten weeks for aluminium — from confirmed order to delivery.
- 04Subtract survey and confirmation timeAllow a further one to two weeks for a technical survey (or drawing-based measurement on a new build) and formal order confirmation.
- 05That gives your order dateWhatever date results is when the order, deposit and final specification need to be locked in — not when you first get a quotation.
Typical lead times by product
Lead times move with demand and with how unusual the specification is, so treat the figures below as planning ranges to confirm at quotation stage, not fixed promises.
| Product | Typical lead time |
|---|---|
| Aluminium windows | 5–8 weeks |
| Aluminium sliding doors | 6–9 weeks |
| Aluminium bifolding doors | 6–10 weeks |
| Timber-look uPVC (Residence Collection) | 4–7 weeks |
| Vertical sliding sash windows | 5–8 weeks |
| Bespoke colours or oversized units | add 1–3 weeks |
What must be fixed before you can order
Ordering prematurely, before certain decisions are locked, is the single most common cause of avoidable delay and cost on a self-build glazing package.
- Structural opening sizes confirmed on approved construction drawings
- Planning permission granted, or discharged if conditions affect glazing (materials, colour, sightlines)
- Frame colour and finish decided, both internally and externally if they differ
- Glass specification agreed, including any solar control or acoustic requirements
- Opening configuration confirmed — which sashes open, door handing, hardware finish
- Building control route agreed, since Part L calculations may affect glazing specification
When should windows be measured on a new build?
On a new build there are two measuring points, and knowing which one you are at is what keeps the programme honest. The first is a drawing-based measurement, taken from approved structural drawings once opening sizes are frozen — usually at foundation or early superstructure stage. That is what allows the order to be placed early enough to protect the watertight date. The second is a check-measure on site, taken once the structural openings physically exist and before manufacture starts.
| Stage | When it happens | What it is for |
|---|---|---|
| Drawing-based measurement | Once opening sizes are frozen on approved drawings | Placing the order early enough to hold the programme |
| Site check-measure | Once openings are built, blockwork or timber frame complete, before manufacture | Catching discrepancies between drawing and site |
| Final confirmation | Immediately after check-measure | Releasing frames to manufacture at confirmed sizes |
The practical answer for most self-builds is: measure from drawings to place the order, then have the supplier attend site for a check-measure as soon as the openings are formed and square, typically once the shell is up and before the roof is finished. Measuring earlier risks working from sizes that have not been built yet; measuring later pushes manufacture past the point where the building can be made watertight on time.
- Openings should be complete, square and dimensionally stable before a check-measure — not partially built.
- On timber frame, measure after the frame is erected; on masonry, after the blockwork and lintels are in.
- Allow one to two weeks between check-measure and manufacture starting, for confirmation and sign-off.
- If drawings and site differ, resolving it at check-measure costs days; discovering it on delivery day costs weeks.
Self-build-specific considerations
New-build openings are usually measured from drawings rather than an existing structure, which shifts risk in a way worth understanding. If the frame is oversized or undersized because the structural opening was built slightly off the drawing, the discrepancy shows up on delivery day, not before.
Many self-builders manage this by having a supplier attend site for a check-measure once openings are actually built, rather than relying purely on drawings, as set out in the section above.
It is also worth ordering with some contingency built in. Self-build programmes shift; a scaffolding delay or a wet spell affecting groundworks can easily move your watertight date by two or three weeks. Ordering slightly ahead of the theoretical latest date gives you a buffer rather than a crisis.
Decision criteria: are you ready to order?
| Question | If no… |
|---|---|
| Are structural openings fixed on approved drawings? | Wait — sizes may still move |
| Is planning permission granted or conditions discharged? | Confirm before committing to materials |
| Is your builder's programme firm enough to give a watertight date? | Use a provisional date with contingency |
| Have you chosen colour, glass and hardware? | Get these confirmed before placing the order |
| Do you have a deposit ready? | Lead time only starts once order is confirmed |
Common mistakes
- Getting a quotation early, then assuming the lead-time clock has already started
- Ordering before planning conditions on materials or colour are discharged
- Ignoring contingency and ordering to the earliest possible date, leaving no slack for site delays
- Changing opening sizes after ordering without checking the cost and time impact
- Treating self-build glazing like a replacement project, where openings already exist and are simply measured
From a real Windows in the Lakes project
West Yorkshire · 32 windows · 4 doors
32 Heritage Windows and 4 Doors, Stone Self Build
A live self-build programme with 36 openings across four elevations, all in newly dressed stone, several of them non-standard shapes — triangular gables and a full-height narrow light — with no tolerance for cumulative setting-out error across the elevation.
Early involvement with the builder to agree structural opening sizes, then a full measured survey of every opening after the stonework was complete and before manufacture. Georgian bar layouts were drawn as a set rather than window by window, so bar spacing aligns horizontally across each elevation, and the non-standard gable and side-light units were manufactured to survey.
Read the project storyNext step
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