Simon Tolson, construction lawyer with Fenwick Elliot, said he had dealt with three cases of mass adjudications in the past month.
The practice exploits the fact that, under the adjudication process, defendants must respond quickly to a claim. The idea behind a mass attack is that a contractor may concede more ground if it is inundated with notices.
Other lawyers have confirmed that they are starting to see ambushes. One said he was facing an ambush on a large City of London scheme that could paralyse the project.
Contractors and clients warned in the run-up to the introduction of the Construction Act that specialists would use adjudication in this way. Regardless of their complexity, claims must be resolved in 28 days.
Tolson said he had been ambushed twice and had taken part in one ambush. In one case, where he represented a main contractor, a scaffolding subcontractor, joinery firm and plastering company served adjudications on a housing scheme claiming £15 000-40 000.
Tolson said that the subcontractors served notices over three weeks to maximise their leverage. Under the procedure, he had nine days from the day each notice was served to submit a defence to the adjudicator.
He said: “The problem is pulling QSs and project managers off site and getting them to respond to the points. This is hard enough to do if there is one claim, yet alone three.”
The subcontractors in the case he cited made no secret of the fact that they had compared notes and that incidents were cross-referenced, said Tolson. This meant extra work for the project staff, who had to make sure responses were consistent for each defence, he added.
Although Tolson was able to strike a deal with one subcontractor, the other cases are still unresolved.
Some specialists also wait for an inconvenient time to serve a notice, said Tolson. He said that in one claim against a local authority, he waited until the project manager was on holiday before serving it.