How to Check a Builder's Quote Before You Accept It

You may have one builder quoting £45,000, another quoting £58,000 and a third offering to complete what appears to be the same work for £37,000.

The problem is that building quotations rarely include exactly the same things.

A lower price may exclude structural work, decorating, waste removal, building control fees or materials that another builder has included. It may also contain unrealistic allowances that increase once the project begins.

Before accepting a quotation, you need to understand exactly what you are buying.

At Chat to Your Builder, we help UK homeowners understand building quotes, spot missing items and ask the right questions before committing to a builder.

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Quick answer: What should a builder's quote include?

A good builder's quote should clearly state:

• The full scope of work
• Labour and material costs
• The drawings and specifications used
• Fixtures and finishes included
• Provisional sums and allowances
• Items that are excluded
• Whether VAT is included
• The payment schedule
• The expected project duration
• How variations will be priced
• Waste removal and site protection
• Guarantees, certificates and insurance details

The more detail included in the quote, the easier it is to compare builders and control your final costs.

Why checking a builder's quote matters

Many building disputes do not begin because a builder is dishonest. They begin because the homeowner and builder had different understandings of what the quotation included.

A homeowner might assume that decorating, floor finishes or electrical fittings are included. The builder may have priced only the basic construction work.

Once the project starts, these misunderstandings become expensive. A properly reviewed quote can help you avoid:

• Unexpected additional costs
• Arguments over what was included
• Unrealistic payment demands
• Delays caused by missing decisions
• Choosing a builder based on an incomplete price
• Spending beyond your renovation budget

A builder's quote should not simply tell you the total cost. It should explain how that total has been reached.

1. Confirm whether it is a quote or an estimate

The first thing to check is whether the document is described as a quotation or an estimate.

An estimate is an approximate prediction of what the job may cost. A quotation is normally a more definite price based on an agreed scope of work.

However, even a quotation can change if:

• You request additional work
• The drawings or specification change
• Hidden problems are uncovered
• The quote contains provisional sums
• You select more expensive finishes
• Work has been excluded from the original price

Do not rely on the heading alone. Read the wording carefully to understand which parts of the price are fixed and which can change.

2. Check the scope of work in detail

The scope of work is the description of what the builder has agreed to complete. A quote that simply says "complete rear extension as per drawings" is not detailed enough for most significant building projects.

A more useful quotation should separate the work into sections such as:

• Site setup
• Demolition
• Groundworks
• Foundations
• Drainage
• Structural steelwork
• Brickwork and blockwork
• Roofing
• Windows and doors
• Insulation
• Plumbing
• Electrical work
• Plastering
• Carpentry
• Flooring
• Decorating
• External works
• Waste removal

This makes it much easier to identify omissions and compare the quotation against another builder's price.

Warning sign: Be cautious when a large project is presented as a single price with little supporting detail. The less information shown, the harder it will be to prove what was agreed if a disagreement occurs later.

3. Make sure every builder priced the same information

You cannot properly compare building quotes unless every builder has received the same documents. Each builder should ideally price from the same:

• Architectural drawings
• Structural engineer's drawings
• Schedule of works
• Written specification
• Kitchen and bathroom plans
• Window and door information
• Electrical layout
• Finishing requirements

For example, one builder may have allowed for aluminium doors while another has allowed for standard uPVC doors. One quote may include decorating throughout, while another may stop at bare plaster.

Both builders may believe they have quoted correctly, but they have not priced the same finished project. Before comparing totals, ask each builder to confirm which drawings and documents their quotation is based on.

4. Look for items that have been excluded

The exclusions section can be just as important as the price. Common exclusions include:

• Architect's fees
• Structural engineer's fees
• Planning fees
• Building control charges
• Party wall surveyor costs
• Kitchen supply
• Bathroom fittings
• Floor coverings
• Decorating
• Light fittings
• Landscaping
• Scaffolding
• Skip permits
• Utility upgrades
• Temporary accommodation

An exclusion is not automatically a problem. The important point is that you know about it and include the cost in your overall renovation budget.

A quote of £80,000 with several major exclusions may be more expensive than a £90,000 quote that includes everything required to complete the project.

5. Check provisional sums carefully

A provisional sum is an allowance for work that cannot yet be priced accurately. For example: "Drainage alterations: provisional sum of £3,000."

This does not necessarily mean the drainage work will cost £3,000. The final cost may be lower or considerably higher, and large provisional sums reduce the certainty of your building budget.

For each provisional sum, ask the builder:

• Why can this work not be priced accurately now?
• What assumptions have been made?
• Is the allowance based on a likely cost?
• What happens if the actual cost is higher?
• Will the builder add profit or management charges?
• Will you see supporting invoices?

A quote with a low total but several unrealistic provisional sums can become much more expensive after work begins.

6. Check the allowances for fixtures and materials

A quotation may include allowances for products that you have not selected yet. These may include kitchen units, sanitaryware, taps, tiles, flooring, internal doors, ironmongery, light fittings and appliances.

Check whether the allowance is realistic for the quality you expect. For example, a £20-per-square-metre tile allowance will not be sufficient if you intend to choose tiles costing £60 per square metre.

You should also ask whether the allowance covers:

• Supply only
• Delivery
• Installation
• Adhesives and associated materials
• VAT
• The builder's margin

A small difference in the allowance for each item can add thousands of pounds to the final cost of a renovation.

7. Check whether VAT is included

Always confirm whether VAT is included in the quoted total. A quotation of £50,000 excluding VAT could become £60,000 once VAT is added at the standard rate. The quote should make this completely clear.

Be cautious if a builder suggests that a large project can be paid entirely in cash to avoid VAT or without proper invoices. You may have very little protection if a dispute occurs.

8. Review the payment schedule

A reasonable payment schedule should reflect the progress of the work. Common arrangements include:

• An initial deposit
• Stage payments
• Payments linked to completed work
• A final payment after completion
• A retention held until defects are corrected

Avoid paying a very large percentage of the contract value before substantial work or materials have been provided. The quotation or contract should explain the deposit amount, when each payment becomes due, what stage must be completed, how invoices will be issued, whether materials are paid for in advance, and how disputed work will be handled.

Never rely solely on verbal promises about payments.

9. Ask how additional work will be agreed

Changes during a building project are common. You might decide to add more electrical sockets, change the flooring or alter part of the layout. Unexpected work may also become necessary once walls or floors are opened.

The builder should explain how variations will be handled. Ideally, additional work should be described in writing, priced before it is completed, approved by you, and added to the running project cost.

Without a clear process, several small changes can result in a large and unexpected final bill.

10. Check the proposed timescale

The quote should state when the builder expects to start and approximately how long the project will take. Ask whether the proposed duration includes ordering materials, specialist subcontractors, building control inspections, drying time, kitchen or window lead times, external works, and decoration and completion.

A very short programme may appear attractive, but it needs to be realistic. You should also ask what happens if the work takes substantially longer than expected.

11. Check insurance, guarantees and certificates

Before appointing a builder, ask for details of their insurance. Depending on the project, this may include public liability insurance, employers' liability insurance, contractors' all-risk insurance, and professional indemnity insurance for design work.

You should also confirm who will provide any necessary electrical certificates, gas certificates, building control completion certificate, window certification, roofing guarantees and product warranties.

These documents may be important when you sell the property, remortgage it or make an insurance claim.

12. Compare the details, not only the final price

When comparing builders, create a simple table showing what each quote includes.

Item	Builder 1	Builder 2	Builder 3
Foundations	Included	Included	Included
Structural steel	Included	Provisional	Excluded
Windows	Aluminium	uPVC	Not specified
Electrical work	Full installation	Basic allowance	Included
Decorating	Included	Excluded	Excluded
Waste removal	Included	Included	Not specified
VAT	Included	Excluded	Unclear

This often explains why one builder appears much cheaper than another. The aim is to compare the cost of reaching the same finished result.

Is the cheapest builder's quote usually the best?

Not necessarily. A cheaper quotation may represent good value, but it may also indicate missing work, low allowances, a misunderstanding of the drawings, underestimated labour, lower-quality materials, too few workers, or an intention to recover profit through extras.

This does not mean you should automatically choose the most expensive builder either. The strongest quotation is usually the one that is detailed, realistic and based on a clear understanding of your project.

Questions to ask before accepting a builder's quote

Before signing anything, ask the builder:

1. Is this a fixed quotation or an estimate?
2. Which drawings and specifications have you priced?
3. What work is excluded?
4. Which items are provisional?
5. Are all prices inclusive of VAT?
6. Who pays building control and professional fees?
7. How will variations be priced?
8. What is the payment schedule?
9. What insurance do you carry?
10. Who will supervise the project?
11. What certificates will be provided?
12. Can I speak to recent clients?
13. When can you start?
14. How long should the project take?
15. What could cause the price to increase?

A professional builder should be comfortable answering reasonable questions about their quotation.

Builder quote warning signs

Take extra care if:

• The quote is only a few lines long
• The price is much lower than every other quote
• VAT is not mentioned
• There is no company address
• The builder wants a large cash deposit
• Major items are marked as provisional
• The quote does not refer to your drawings
• The payment schedule is heavily front-loaded
• Exclusions are unclear
• The builder refuses to put changes in writing
• You are being pressured to decide quickly
• The builder cannot provide recent references

One warning sign does not automatically mean the builder is unsuitable, but it should prompt further questions. If you'd rather not weigh it up alone, see the full builder quote red flags guide for a deeper breakdown of each of these signs — or send us the quote directly.

Upload Your Builder's Quote for Review

Should you have a builder's quote independently checked?

For a small repair, an independent review may not be necessary. For an extension, loft conversion, major refurbishment or structural project, having a quote reviewed can be extremely valuable.

An independent review may identify missing work, unclear allowances, unrealistic provisional sums, payment risks, conflicts between the quote and drawings, and areas that need clarification before you sign.

Finding a missing £10,000 item before work starts is far easier than discovering it halfway through the project.

Get your builder's quote checked by Chat to Your Builder

Not sure whether your builder's quote is fair, complete or realistic? Chat to Your Builder provides independent, practical advice for UK homeowners before and during building work.

You can send us your builder's quotation, architectural drawings, specifications, and your questions and concerns. We can help you understand what the quote actually includes, which costs may be missing, which allowances could increase, what questions you should ask, whether the payment structure appears reasonable, and how the quote compares with the proposed work — for context, it's worth reading our house extension cost guide alongside your quote if you're extending.

Our advice is designed to help you make a more informed decision before committing thousands of pounds to a building project.

Final builder quote checklist

Before accepting a quote, confirm that:

• The builder priced the correct drawings
• The scope of work is detailed
• Materials and finishes are specified
• Exclusions are clearly listed
• Provisional sums are realistic
• VAT is included or clearly shown
• The payment schedule is reasonable
• Additional work must be agreed in writing
• The builder has suitable insurance
• The start date and duration are stated
• Certificates and guarantees are included
• You have checked references
• You understand the likely final cost

Do not be afraid to ask questions. A reliable builder should want both sides to understand what has been agreed before the project starts.

Already received a quote? Send it to Chat to Your Builder for an independent review before you sign or pay a deposit.