What should a specification of works include?
The short answer
A specification of works is the written description of what is to be built and to what standard. At minimum it should cover the scope of work, materials, workmanship expectations, preparation, installation requirements, finishes, the interfaces between trades, and a clear list of exclusions. Its job is to remove assumptions, so that builders price the same job and you can tell whether the work you receive is the work you asked for.
Key points
- Drawings show what it looks like; the specification says what it is and how well it must be done.
- Exclusions are as important as inclusions.
- Interfaces between trades are where most on-site disputes begin.
- A pricing schedule turns a specification into something you can compare.
- A specification is not a contract on its own, but it is the document a contract usually refers to.
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Example: make a vague flooring item clearer
“New kitchen floor” leaves decisions open. Record the room and drawing reference, measured area, chosen finish or supply allowance, preparation, installation requirements, trims, thresholds, making good and waste removal.
A draft request might read: “Kitchen floor finish to the agreed product and layout. Confirm measured area and substrate preparation before pricing. State who supplies and installs the finish, and whether trims, thresholds and removal of existing flooring are included.” This illustrates information to resolve, not a technical installation specification.
- Mark undecided products as decisions outstanding.
- Have the designer or relevant specialist specify technical performance and preparation.
- Issue the same dated specification and drawing revision to every builder.
Scope of work
State plainly what is being done, where, and what is being left alone. Room by room or element by element is usually clearer than a single narrative paragraph. Include the sequence where it matters, and say who provides access, welfare, power and waste removal.
Materials
Name the materials, or describe the performance the material must achieve. If a particular product is required, say so and state whether equivalents are acceptable and who approves them. Where you have not decided, mark the item as provisional so it is visibly not a fixed price.
Workmanship expectations
Describe the standard of execution: tolerances, alignment, joint treatment, fixing methods, and the reference standards or manufacturer instructions to be followed. 'To a good standard' means different things to different people; a written standard does not.
Preparation
Protection of existing finishes, floor coverings and neighbouring property; setting out; removal of existing elements; making good; and the condition surfaces must be in before the next trade starts.
Installation
How components are to be installed, fixed, sealed, insulated and tested, and which installations require certification or sign-off by a registered competent person.
Finishes
Decoration systems and numbers of coats, tiling layouts, flooring, joinery finishes, ironmongery and sealant colours. These items are highly visible and frequently under-specified.
Interfaces between trades
Say who is responsible where two trades meet — for example who forms and seals the junction between the new roof and the existing wall, or who makes good after first fix. Unassigned interfaces are the most common source of 'that wasn't in my price'.
Exclusions and assumptions
Record what is deliberately not included: fees, surveys, decoration to existing rooms, landscaping, appliances, unknown ground conditions. Also record the assumptions the specification depends on, so that if one turns out to be wrong everyone can see why the cost changed.
Contractor pricing
Provide a pricing schedule that follows the structure of the specification, so each contractor returns a price against the same items. That makes comparison arithmetic rather than interpretation, and makes variations far easier to value later.
Why a written specification helps
Most build disputes are not about dishonesty; they are about two people remembering a conversation differently. A written specification narrows what can be assumed, and gives both sides a shared reference when something needs to change.
Things to check
- Does every section describe both what is included and what is excluded?
- Is every material either named or described by required performance?
- Has each trade interface been allocated to somebody?
- Are provisional items clearly marked as provisional?
- Does the pricing schedule mirror the specification structure?
- Are certification and testing requirements stated where they apply?
Turn your project into a written scope of works
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Specification of Works — Coming soon
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This guide is general information for UK homeowners. It is not legal, planning, structural or professional advice, and it does not take account of your individual circumstances. Rules change and vary between England, Wales, Scotland and Northern Ireland, and by local authority.
KEZARIQ provides guidance and documents you complete and review yourself. It does not manage your project, carry out professional services, or replace an architect, surveyor, structural engineer, planning consultant or other competent professional where one is required. Nothing here guarantees planning permission, Building Regulations approval, prices, contractor performance or any project outcome. You remain responsible for your own project and decisions.