Question 1

What is a provisional sum, and why do quotes change?

Accepted Answer

An **allowance included in a price for work that cannot yet be defined** — and understanding it is the key to knowing which parts of a builder's quote are firm and which are not.

**What it is.** Where an element of work is known to be needed but cannot be priced accurately — because the extent is unknown until something is opened up, or the specification has not been decided — a **provisional sum** is included as a placeholder. When the work is defined, the sum is **omitted** and the actual cost substituted.

**Typical examples:** rewiring of unknown extent; repairs to structure that cannot be seen until finishes are removed; drainage alterations; and remedial work to floors or roofs discovered during the job.

**Prime cost (PC) sum** is the related term, and it is different: an allowance for a **specified item you will choose later** — sanitaryware, tiles, a kitchen, ironmongery. The **labour to install it is priced**; only the item cost is an allowance. Choose something dearer and you pay the difference; choose something cheaper and you should be credited.

**Why quotes change, in order of frequency:**

**Provisional sums resolving at a different figure**, which is expected behaviour rather than a problem.

**Variations** — changes you requested. **These are the largest cause of overruns**, and they accumulate through many small decisions rather than through one big change.

**Discovering conditions nobody could see** — inadequate foundations, rotten timber, asbestos, services in unexpected places.

**Specification drift**, where better materials are chosen as the job progresses.

**Errors in the original pricing**, which are the contractor's risk on a fixed price and frequently become an argument.

**How to keep control:**

**Minimise provisional sums** by investigating first — opening up and surveying before pricing costs money and costs less than the alternative.

**Require variations in writing, priced, before the work is done.** This single practice prevents most disputes, and the resistance you meet when asking for it is informative.

**Keep a contingency** — commonly 10–20% on refurbishment, more on older buildings — as a separate figure you expect to spend rather than hope not to.

**Ask what is excluded**, which is where the real gaps sit.

Question 2

What should a builder's quote include?

Accepted Answer

Enough detail that you could give it to a different builder and get a comparable price — if you cannot, it is an estimate dressed as a quote, and that ambiguity is where disputes originate. What a

Question 3

What is a schedule of works, and why does it matter?

Accepted Answer

A detailed written description of exactly what is to be done, item by item — and it is the single most effective protection against disputes on a building project, because most disputes are about

Question 4

What is retention in a building contract?

Accepted Answer

A percentage of each payment withheld by the client until the work is demonstrably complete and any defects appearing within an agreed period have been corrected — an incentive for the contractor to

Question 5

Do I really need to use primer before painting?

Accepted Answer

Sometimes, and skipping it when it is genuinely needed is one of the most common reasons a paint job fails within a year. The useful question is not whether primer is always required but what

Question 6

What is an insurance-backed guarantee, and is it worth anything?

Accepted Answer

An insurance policy that stands behind a contractor's own guarantee, so that the guarantee remains usable if the contractor ceases to trade — which is precisely when a guarantee is otherwise

Question 7

How to finish a basement on a budget?

Accepted Answer

Finishing a basement on a budget is achievable with DIY efforts, affordable materials, and strategic planning. Focus on essential areas and repurpose items for cost savings.

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