Pricing an extension or refurb job without guessing half of it

Extension and refurb jobs get priced on the back of a fag packet more than almost anything else in the trade. The drawings are often thinner than a new build, the client wants a number quickly, and there's a temptation to price it off experience and a walk round the property rather than measuring it properly. That works fine right up until the ground's opened up or the existing structure turns out to be worse than it looked.

Why these jobs are harder to price than they look

A new build gives you a clean set of drawings and a site with nothing in the way. An extension or refurb gives you an existing building to tie into, structure you can't fully see until it's opened up, and services that were never drawn accurately in the first place. Pricing that by feel means you're absorbing whatever the walls turn out to hide.

Measuring it properly instead

The fix isn't more experience, most contractors pricing these jobs already have plenty of that. It's measuring what's actually shown on the drawings, item by item, rather than pricing the whole job as one lump figure based on a similar extension from last year. Groundworks, structural openings, first and second fix, external works, all measured separately so the price reflects this job, not an average of the last five.

What to build in for the parts you can't see yet

Every refurb has an element you genuinely can't quantify until it's opened up: what's behind that wall, what state the existing drainage is in. That's not a reason to guess the whole price. It's a reason to measure everything you can see properly, so any provisional allowance you carry for the unknown parts is a small, honest figure sitting on top of a solid number, not a cover for not measuring the rest of the job at all.

Getting the drawings measured

Send us whatever you've got, plans, sketches, or a scheme drawing, and we'll measure the job to NRM2 and price it on current UK rates, so the bulk of the job is priced from real quantities and only the genuinely unknown parts are left as an allowance. That's the approach behind 25+ years contractor-side pricing this exact type of job.

Send your drawings before you quote the next extension or refurb, and price it from measured quantities instead of a walk round and a gut feel.

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