What Should an Extension Quote Include?

The scope, in enough detail to argue with

A quote should describe the work stage by stage, not in a single paragraph. Groundworks and foundations, drainage, structure and steels, roof, windows and doors, first fix, plastering, second fix, decoration, external works and making good.

If you cannot tell from the document what will and will not be done, you cannot hold anyone to it later, and neither can they defend themselves.

The line items to look for

These are the ones most often absent, and each one is capable of moving the total noticeably.

Scaffold, including how long it is allowed for · Skips and muck away, and who pays if the ground yields more spoil · Building control charges, and whether the builder or you pays them · Structural steel supply, fabrication and installation · Making good to existing rooms opened into · Decoration, and whether it is included or excluded · Kitchens, appliances, sanitaryware and flooring, priced or excluded · Welfare, site protection and cleaning

Provisional sums and what they mean

A provisional sum is an allowance for work that cannot yet be priced accurately, most often foundations before the ground is open. It is a legitimate and honest device, not a trick, but it is not a fixed price for that item.

What matters is that provisional sums are clearly identified, few in number, and that the quote says how the final figure will be established. A quote that is mostly provisional sums is an estimate dressed as a quote.

Payment terms

Expect payments tied to completed stages rather than to dates, with the amount reflecting work actually done. A modest deposit for materials procurement is normal. A large payment before anything happens is not.

There should also be a retention or a final payment held until snagging is complete and any certificates have been handed over.

Programme, insurance and the paperwork at the end

A quote should carry a programme with stage dates, confirmation of public liability insurance, and a statement of what will be handed over on completion: building control completion certificate, electrical certification, gas safety documentation where relevant, and any guarantees.

That closing paperwork is what a buyer's solicitor asks for years later, and its absence is a genuine problem at the point of sale.

Warning signs

A single line total with no breakdown. Pressure to decide quickly. A large upfront payment. No written programme. Reluctance to provide insurance details. A price conspicuously below the others, which usually means something has been left out rather than that a bargain has been found.

Frequently asked questions

How many quotes should I get?

Three is the usual advice and it works, provided all three price the same drawings and specification. Three quotes for three different scopes tell you nothing.

Is the cheapest quote a problem?

Not automatically, but a large gap is worth investigating line by line. Most of the time the difference is an exclusion rather than efficiency.

What deposit is reasonable?

Enough to cover materials being ordered, not a substantial share of the contract value. Payments should follow work completed.

Should the quote include VAT?

It should state clearly whether the figure includes or excludes VAT, and whether the contractor is VAT registered. Comparing an inclusive quote with an exclusive one is a common and expensive mistake.