The short answer
Usually far more than the rework log suggests, because the log records the remake and misses the return trip, the management time, the delay and the work you couldn't take on. UK construction research puts the direct cost of avoidable error at around 5% of project value, and the full cost at 10–25% once hidden costs are counted.
By Euan Pallister, Operations & Quality Improvement Consultant. Published on .
Why the log understates it
Most businesses that quote, make and install keep some record of remakes. Very few keep a record of everything a remake sets off. A typical rework log has a date, a job number, a description and perhaps the cost of new materials. What it leaves out is usually bigger:
- The return trip. A fitter and a van going back to a job that was meant to be finished, often to a site that is now harder to get onto.
- Office and management time. Re-drawing, re-ordering, chasing the supplier, rescheduling the fitting team and calming the client.
- Supplier costs you absorbed. Replacement parts you paid for because there was no route to charge them back.
- Delay. Retentions held longer, final accounts argued, and sometimes damages.
- Lost capacity. The day a team spends redoing the last job is a day it doesn’t spend on the next one. In a busy year that is margin you never get to quote for.
What the research says
There is no published rework figure for UK joinery or fit-out on its own. The nearest reliable evidence is for UK construction as a whole. The Get It Right Initiative (GIRI) found that the measured direct cost of avoidable error is in the order of 5% of project value, which is higher than typical profit margins in the sector. When unrecorded waste, latent defects and indirect costs were added, GIRI’s estimates of the total rose to between 10% and 25% of project cost.
Treat those numbers as a sense of scale, not a benchmark for your business. Your own figure is the only one that matters, and it can be built from records you already keep.
How to put a figure on your own rework
You don’t need a new system. You need last year’s records and an afternoon.
- Count the incidents. Pull remakes, remedial visits, credit notes and replacement orders for the last 12 months. Include the ones that were sorted out informally if anyone remembers them.
- Group them into families. Measuring errors, missing items, wrong finish or handing, supplier faults, damage in transit. Most businesses find that three or four families make up most of the cost.
- Agree a cost per incident with finance. Keep it conservative: labour at your internal rate, materials, the van and travel, and an allowance for office time. A figure the board believes is worth more than a big one it doesn’t.
- Multiply and add up. Incidents per family × cost per incident. Then compare the total with your annual gross profit.
The cost of poor quality calculator does steps 3 and 4 for you and shows the formula, so you can check it.
A worked example
This is an illustration with round numbers, not a client’s figures. Adjust every line to your own.
| Item | Assumption | Cost |
|---|---|---|
| Remakes in the workshop | 60 a year × £450 materials and labour | £27,000 |
| Return visits to site | 90 a year × £380 (two fitters, van, half a day) | £34,200 |
| Office time on each incident | 150 incidents × 2 hours × £35 | £10,500 |
| Supplier faults not charged back | 25 a year × £300 | £7,500 |
| Total | £79,200 |
For a business turning over £5m at a 25% gross margin, £79,200 is about 6% of gross profit, earned on jobs priced correctly and then spent putting them right.
What to do with the figure
The point of the number is to choose what to fix first. Rank the families by cost, not by how annoying they are, and look at the top two or three. For each, ask two questions: where did it start, and why didn’t a check catch it? Our guide to where margin leaks walks through the twelve places it usually starts, from quote to invoice.
If you’d like a second pair of eyes on your records, the free Margin Leak Review takes about an hour and you keep what we find.
Quick answers
What counts as rework?
Any work done a second time because it wasn't right the first time. That includes remakes, adjustments on site, replacement parts, re-deliveries and remedial visits, whether or not anyone logged them.
Why is our rework log so much lower than the real cost?
Most logs record the direct remake and nothing else. Return trips, office time, supplier chasing and the job you couldn't start because a team was redoing the last one rarely get a line.
What is a typical rework cost for a UK project business?
There is no reliable figure for joinery or fit-out on its own. For UK construction as a whole, the Get It Right Initiative found direct avoidable error of around 5% of project value, and estimated the total at 10–25% once hidden costs are included.
How do we work out our own figure quickly?
Count last year's remakes and return visits, agree a conservative cost for each with finance, and multiply. The free calculator does this and shows its formula.
Sources
- GIRI member profile, direct cost of avoidable error around 5% of project value (New London Architecture)
- Pressing pause to avoid errors (GIRI), total cost of error estimated at 10–25% of project cost (Designing Buildings Wiki)