Should sizes be exact on a quotation?

Not necessarily. Quotation sizes are based on the information available at the time; the detailed survey after order produces the final manufacturing dimensions. What matters is that the document says so clearly.

Is a short quotation always a bad sign?

No. Brevity is fine if the essential facts are present. Length is not a substitute for specificity.

Buying Guides

What Are the Warning Signs of a Poor Glazing Specification?

A good specification is specific. If you cannot tell from the paperwork exactly what will arrive on site, neither can the factory.

3 min read

Written by Windows in the Lakes · A trading name of Home Glazing Ltd · Last reviewed 21 September 2026

Short answer

In short: the warning signs are all versions of the same problem — the document describes an intention rather than a product. This guide lists what to look for. It is not about any particular supplier, and a document missing one of these things is worth a question rather than an accusation.

Ten things worth querying

01A material name where a system name should be — "aluminium windows" rather than a named system and profile range.
02Glass described only as "double glazed", with no unit make-up, coating or gas fill.
03No mention of safety glass, when critical locations near doors and at low level normally require it.
04Hardware unnamed, or described only as "quality hardware".
05No colour reference, or a colour name instead of a RAL reference and finish.
06A threshold detail left undefined on a door opening, particularly where a level threshold is expected.
07Panel sizes that look ambitious for the system, with no note about weight, handling or restrictions.
08No statement of who is responsible for making good, internally and externally.
09No exclusions section at all — every honest quotation has one.
10No explanation of how Building Regulations compliance will be certified.

What a good specification reads like

Each opening: Identified with a location reference and a configuration
Sizes: Stated, with a note that they are confirmed at post-order survey
Glass: Specified per opening, including safety and solar requirements
Colour: RAL reference and finish, inside and outside
Hardware: Named range and finish
Scope: Removal, installation, sealing, making good and disposal set out
Exclusions: Clearly listed, including anything by others
Guarantee: What is covered, by whom and for how long

How to raise it

Ask for the missing detail in writing and judge the response rather than the omission. A capable supplier will fill the gaps quickly and without irritation, because they have the information already. A long delay or a vague answer tells you something the price cannot.

Terms used in this guide

U-value: The rate at which heat passes through a building element, in W/m²K. A lower number means less heat loss. Window U-values may be quoted for the glass alone or for the whole window; the whole-window figure is the comparable one.
g-value: The proportion of solar energy passing through the glass, between 0 and 1. A lower g-value admits less solar heat, which matters on south and west-facing glazing.
Sightline: The visible width of frame seen across a window or door — outer frame, meeting stile and any glazing bar. Slimmer sightlines mean more glass and more daylight for the same opening.

Sources and further reading

Regulatory and technical points in this guide should be checked against the current published guidance below, and against the specific circumstances of your property.

Guidance last reviewed 21 September 2026 by Windows in the Lakes

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