What is a listed building window survey and when do you need one?
What a listed building window survey records, who it is for, and when you need one, from the surveyors who write them, reviewed against current guidance.
A listed building window survey is an independent record of every window in scope: what is original, its condition, whether it can be repaired, and what the local authority is likely to accept. You need one before a listed building consent application involving windows, before major works are scoped, and whenever someone has told you the windows are beyond saving.
Reviewed by Heritage Window Consultants
What does the survey record?
Every window, door and shutter you ask us to look at is given a reference and inspected in turn. The record covers the box frame, the sashes, the sill, the glazing bars, the cords, weights and pulleys, the ironmongery and the glass, and it states which of those are original and which are later work.
Each window then receives an urgency grade and a recommendation to repair, part-renew or replace, with the reasons written out, so that a contractor can price from the report and a conservation officer can rely on it, both working from the same document.
Who needs one, and when?
Homeowners commission one when a builder has said the windows must go and they would like that tested. Architects commission one so that the window evidence beneath a heritage statement comes from a practice that is not competing for the work. Estates and managing agents commission one to get every window on a register before works are scoped or leaseholders are consulted.
The most useful moment is before the drawings are finished, because a survey that arrives after a design is fixed tends to be read as justification rather than evidence.
How is it different from a building survey?
A building survey looks at the whole property and will usually say no more about the windows than that they are in fair or poor condition, which is not enough to support an application and not enough to price from.
A window survey works part by part, window by window. Section sizes are taken where the timber is exposed, the glazing is identified, and the recommendation distinguishes the box from the sashes from the glass, because those three parts are very often in different condition and do not have to share the same fate.
What does the finished report look like?
It opens with the instruction and the method, then gives a summary schedule of every window before the window-by-window findings. The schedule is the part most people use, because it carries the priorities and the totals in one view.
Each window takes a code, a location, an urgency grade and a recommendation, and those codes then run through the photographs and the detailed findings, so that everyone reading the report is looking at the same window. Reports stay confidential to the client who commissioned them, which is why we do not reproduce them here.
Primary sources
Common questions
How many windows does a survey have to cover?
As many as you need, from a single window to several hundred, and where an estate is too large to inspect in full at the outset, a representative sample survey sets the scope and budget first.
Do you need access to the inside of every room?
Yes, wherever a window is to be assessed in full. Where access is restricted, the report says so and records what could not be seen, rather than guessing at it.
Can the report be used for a listed building consent application?
Yes. The findings are written so that they can be cited in a heritage statement, and the photographs are referenced to the same codes used in the schedule.
Who owns the report?
You do. It is issued as a PDF, and most clients pass it to their own architect or contractor.
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- Heritage Window Consultants Ltd
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