Site diary for a house extension: what to record

A house extension is a small job with an outsized risk of a dispute, because the customer lives on the other side of the wall and asks for changes every day. The daily site diary is what separates the work you quoted from the extras you were asked for, and it is your evidence trail for every building control inspection. This guide sets out what an extension diary should capture, a worked example of a real day, and how to log it from your phone so the client instructions are never in doubt.

What a site diary for a house extension needs to capture

On a domestic extension the record has to lean hardest on client instructions and building control, because that is where money and sign-off are won or lost. Record these every day:

• Client instructions and changes. Anything the homeowner asked for that differs from the original scope, with the date, exactly what was requested and any cost or time you flagged. This is the single most valuable entry on an extension
• Building control inspections. Foundation, damp proof course, drainage, insulation and completion visits, with the date, outcome and a photo of the stage inspected
• Work completed. What was done and where, from foundations and blockwork to steel, roof, first fix and second fix
• Covered-up work. Foundations, damp proofing, cavity trays, steel beams and padstones, and services, all photographed before they are hidden
• People on site. Your team and any subcontractor such as electrician, plumber, plasterer, with numbers
• Deliveries. Materials, steel, windows and units delivered, with any damaged or rejected loads
• Weather and stoppages. Rain, frost and any time lost, with the reason
• Access and disruption. Anything about working next to an occupied home, such as agreed working hours, access arrangements or party wall matters
• Inspections and safety. Any safety check or incident, and toolbox talks

A worked house extension diary example

Here is what a solid entry looks like for a single day on a single-storey rear extension. It is illustrative only, but it shows the detail that keeps the final account clean.

Wednesday. Weather: dry, mild. On site: 2 bricklayers, 1 labourer, plus building control officer in the morning. Work: continued cavity blockwork and outer leaf brickwork to rear elevation, three courses above DPC, cavity trays and weep vents installed to the specified detail. Building control: DPC and cavity tray inspection at 10:30, passed, no comments. Instruction: homeowner asked at 12:15 to add a second double socket to the rear wall and to widen the internal opening by 100mm. Advised both are extra to the original scope, likely cost and time impact confirmed to follow, homeowner agreed to proceed. Deliveries: pallet of facing bricks, all sound. Photos: DPC and cavity trays before further courses, brickwork progress, wider opening marked out. No stoppages.

The socket and the opening are exactly the sort of casual request that turns into an argument at the end. Logged on the day, they are simply agreed extras.

Why it matters on a house extension

Extension disputes are nearly always about money that the customer does not remember agreeing to, or about whether the work was done properly for the completion certificate. The diary is the answer to both.

When the homeowner says "I never asked for that" at final account, a dated entry naming the request, the time and your response settles it. When the work is finished and the covered-up detail is questioned, the stage photo of the DPC, the cavity tray or the steel is the only proof it was right. And the record of every building control inspection is your route to the completion certificate without chasing paperwork. On a job this small and this personal, the diary is what keeps the relationship and the payment intact.

Paper vs phone on a house extension

On an extension the builder is often the site lead, the estimator and the one talking to the client all day. A paper diary loses out because the client instruction gets given in passing and never written down until the job is over, by which point it is a memory against a memory.

Logging from a phone means you capture the instruction the moment it is given, while you are standing there, timestamped and with the client's words fresh. The photo of the covered-up work attaches to the right day on its own. And even on a domestic street the signal can drop behind a house or in a basement, so the tool has to save offline and sync later. A record you can make in twenty seconds is a record you will actually keep.

Frequently asked questions

What should a house extension site diary record each day?

Record the date and weather, who was on site, the work completed, any client instructions or changes to the scope, building control inspections and outcomes, deliveries, and anything covered up such as foundations, damp proofing or steel. On a domestic extension the client instructions and variations are the most important entries, because that is where payment disputes start.

Why do variations matter so much on a house extension?

On a domestic extension the homeowner is on site every day and asks for changes informally, such as moving a doorway or upgrading a finish. If those requests are not logged with a date and who asked, there is no proof they were extra to the original scope, and the builder ends up arguing about payment at the end.

Which building control inspections should be logged on an extension?

Log every building control visit and outcome, typically foundation excavation, damp proof course and membrane, drainage, insulation, and completion. Note the date, who attended and whether it passed, and attach a photo of the stage inspected. This is your evidence trail for the completion certificate.

How does FORGE Command help on a house extension?

FORGE Command lets you log the day and every client instruction from your phone in minutes, attach photos to each entry, and have the record stamped with GPS, weather and time automatically. It works offline, then syncs, and exports a branded PDF for the client or the file. It is a one payment of £39.99 with no subscription.

Related: what a defensible site diary records, site diary for groundworks, snagging list for a new build.