The concrete slab nobody knew was there
On a brownfield housing site your machine hits an old concrete slab under plots 12 to 15. Then a run of old brick foundations, a redundant cast iron pipe, and a buried fuel tank that stops work until the housebuilder's consultant has a look. Your ganger breaks out the slab, digs round the pipe, and gets on with it. Two days of breaker work, extra muck-away and a lot of standing time.
At month end your QS adds a line to the application for obstructions. The housebuilder's QS asks for records. There are three photos on a phone and the ganger's memory.
Why obstruction records are thin
When the gang hits something, their priority is dealing with it and keeping the job moving, not documenting it. The ganger may mention it to the site manager in passing. Time and plant spent on the obstruction are mixed in with the day's other work. And the notification the subcontract may require is not sent, because nobody thought of it at the time.
- Obstructions are dealt with before anyone records them.
- Photos are few, on personal phones, without location.
- The main contractor or housebuilder is told verbally, if at all.
- Time, plant and muck-away for the obstruction are not separated.
- Claims are raised weeks later, with little to support them.
What unrecorded obstructions cost
Breaker time, extra dig, extra muck-away and standing time that you absorb because you cannot show what happened. Disputes that drag on and cloud the relationship with the main contractor or housebuilder. Where a notification was needed and not sent, a weaker position, which is a matter for your commercial team and advisers. And no data on how often ground conditions surprise you, which would help you price the next brownfield job.
The obstruction log we build
- When the gang finds something, the ganger logs it on a phone: photos, GPS and plot location, depth, a description and whether work has stopped.
- The main contractor's or housebuilder's site manager is notified the same day by email with the photos and location, and the notification is recorded.
- Instructions received in response are logged against the obstruction.
- Gang time, plant, breaker hours, extra muck-away loads and materials spent on it are recorded against the obstruction, not the general work.
- Standing time while waiting for a decision is recorded with start and finish times.
- Your QS gets each obstruction as a costed record with its evidence, ready to include in an application or claim.
- A site view shows obstructions on the plan, which helps later when the housebuilder asks what was found where.
| Obstruction | Location | Notified | Resources recorded |
|---|---|---|---|
| Concrete slab | Plots 12 to 15 | Same day, with photos | Breaker, gang, muck-away |
| Old brick foundations | Plot 18 | Same day | Machine and gang |
| Redundant cast iron pipe | Road A | Same day | Gang, disposal |
| Buried tank | Plot 20 | Same day, work stopped | Standing time |
What you are entitled to, and what notice your subcontract requires, is for your commercial team and advisers. We make sure the record and the notification exist.
Obstructions with a paper trail
Every find is recorded while it is in the ground, with photos, location and depth. The main contractor hears about it the same day, in writing. Time and resources spent on it are separated from the general work, so the cost is clear. Your QS includes obstructions in applications with evidence attached, and the conversation with the other side is about the facts rather than memories.
Do obstructions go unpaid on your jobs?
- Gangs deal with obstructions without recording them.
- The main contractor is told verbally.
- Obstruction costs are mixed in with general work.
- Claims are raised weeks later with little evidence.
- You have absorbed the cost of obstructions you could not prove.