Exclusions and assumptions: the two lists that protect your price
Last reviewed 12 September 2026
A price is only fixed against the work you described. These two short lists are what stop the space around that work becoming free.
Every dispute about a final bill is a dispute about scope. The customer believed something was included, you believed it was not, and neither belief was written down. Exclusions and assumptions are how you write it down, and together they take about ten minutes to produce.
The difference between the two
An exclusion is work you will not be doing. An assumption is a condition your price depends on. Exclusions protect the edges of the job. Assumptions protect the price of the job itself.
Exclusions worth listing on nearly every job
- Removal and disposal of waste beyond the items named, and any skip or tip charges.
- Making good decorations, plaster, flooring and finishes disturbed by the work, unless stated.
- Scaffolding, towers, edge protection and any temporary works.
- Works to asbestos-containing materials, and any survey or licensed removal.
- Structural repairs, timber decay and infestation treatment found on opening up.
- Upgrading existing services, boards, pipework or drainage to current standards where that is triggered by the work.
- Statutory fees, building control applications, planning and party wall matters.
- Parking charges, permits, congestion and clean air zone charges.
- Out-of-hours or weekend working.
- Anything not specifically described in the scope above.
That last one is a useful sweeper, but it is not a substitute for the specific items. A single catch-all line reads as small print. A named list reads as professional care, and it is far harder to argue with.
Trade-specific exclusions people forget
- Electrical: lifting and relaying fitted floor coverings, chasing and making good plaster, fire alarm interfaces, and any remedial work arising from the condition of the existing installation.
- Plumbing and heating: system flushing where not stated, gas supply upgrades, flue routes requiring scaffolding, and the condition of concealed pipework.
- Roofing: replacement of defective timbers found once stripped, and works to chimneys, leadwork or party walls.
- Plastering: preparation of unsound backgrounds, and drying and decoration times affecting other trades.
- Joinery: sanding, sealing and finishing where the customer supplies the finish, and out-of-square existing openings.
- Groundworks and drainage: unknown services, obstructions, rock, contaminated ground and disposal classification.
Assumptions worth stating
- The working area will be clear, empty and available for the duration.
- Water, power and welfare facilities are available on site at no charge.
- Safe access is available to all areas, including the loft and the roof, without specialist equipment.
- Existing services and structures are sound and to current standards unless otherwise noted.
- The work will be carried out in continuous consecutive working days during normal hours.
- Prices are based on merchant quotations current at the date of this document and hold for 30 days.
- Where a survey has not been possible, the price is based on visual inspection only.
How to write them so they hold
Three rules. Keep every item to one sentence, because a paragraph reads as an attempt to hide something. Put both lists on the face of the quotation rather than in attached terms, because a customer who has not read a term may not be bound by it, and on consumer work an unclear term is read against the person who wrote it. And explain the important ones out loud when you talk the customer through the price.
What to do when an assumption fails
The moment you find the assumption was wrong, stop and say so. Describe what you have found, what it changes, what it costs and how long it adds, and ask for confirmation before continuing. A written assumption plus a same-day notice makes a variation. A written assumption plus a surprise on the final invoice makes a complaint, and the exclusion list will not save you from it.
The honest test
Read your lists back and ask whether a fair-minded customer, reading them once, would understand what they are buying and what they are not. If the lists are doing anything other than that, they are the wrong lists.
More guides
- How to price a building job so it still makes money
- Quote or estimate: the difference that decides who pays for the overrun
- What a quote must include to be safe in the UK
- How to work out your true hourly rate
- VAT for UK trades, and the domestic reverse charge
- CIS deductions explained, for subcontractors and contractors
- Payment terms, deposits and staged payments
- Variations and extras: how to get paid for work outside the quote
- Why quotes get rejected, and eight fixes that win more of them
- Domestic versus commercial: what changes in the way you quote
- Chasing late payment without losing the customer
Write the quote itself in a couple of minutes
BidReady turns the answers to a short set of questions into a professional quotation with the scope, the exclusions and the terms already in it. Write your first quote free, or see how it works.
This guide is general information for UK trades, written by the BidReady team. It is not legal, tax or financial advice. Rules change and individual circumstances differ, so take professional advice before acting on anything that matters.