Construction job sites that remained open despite the launch of a province-wide labour strike became the target of a sudden 'flash mob' of pickets Wednesday, leading many of those workers to lay down their tools around the Outaouais.

Residential and commercial construction projects around Quebec have been affected by the work stoppage after the union representing 175,000 construction workers launched a general unlimited strike.

Construction companies and labour federations negotiated through the night and into Wednesday morning, but were unable to reach a deal.

Game of cat and mouse

Local union representative Angus Maisonneuve said he got the call this morning that the strike had begun.

A sometimes 40-member strong mobile strike picket moved from location to location to convince reluctant workers to lay down their tools. (CBC)

He spent Wednesday morning in a game of cat and mouse, herding a group of pickets from job site to job site seeking out workers who either hadn't heard the news or may have been reluctant to stop working.

"We don't have to do a lot of convincing when we show up," said Maisonneuve.

Quebec's "anti-scab" law would normally prevent employers from still operating with a replacement workforce, but several employer groups insist the law does not apply to workers in the construction industry, so some sites could stay open if workers agree.

Workers, employers mostly complying with strike

However, several job supervisors decided to comply with the strike as soon as the dozens of pickets arrived waving union placards Wednesday morning. But several workers at those sites expressed mixed feelings.

"When forty guys show up, it's kind of hard to continue," said John-Patrick Gagnon, a worker at one site forced to stop on Amsterdam Boulevard in Gatineau.

'When forty guys show up, it's kind of hard to continue working,' said worker John-Patrick Gagnon. (CBC) "We were just finally starting to get work," said Marc Desjardins at the same site.

Desjardins explained the season began late this year with the wet spring, which makes solidarity challenging.

Strike could cost Outaouais employers $4 million a day

The Outaouais chapter of the Association des professionnels de la construction et de l'habitation du Québec (APCHQ) representing construction businesses suggested the strike could cost employers in the region $4 million each day of the strike.

The APCHQ suggested the strike comes at the worst time for the construction industry in Gatineau, which had had several slow years and was just beginning to pick up.

But some workers will benefit from employers with businesses on both sides of the river.

Some companies have already moved workers to jobs in the Ottawa region.

A site manager for Parisien Construction, a residential and commercial contractor operating Gatineau, said there was a lot of hand-wringing and complaining by workers at a meeting the previous week in anticipation of a strike.

Patrick Germain said many of them are just now beginning to see the return of regular work in construction and they're loathe to stop.

Patrick Germain, site manager for Parisien Construction, said the majority of workers at a recent meeting complained the strike could not have come at a worse time. (Amanda Pfeffer) "A majority of the workers at that meeting were not looking forward to this strike," said Germain.

Young workers may not understand what we're fighting for: union

Maisonneuve said it may be harder for some of the younger workers to understand what the union is fighting for.

He said the employer is trying to change some of the benefits a previous generation of workers battled hard to get.

'We were just finally starting to get work,' said Marc Desjardins, who laid down his tools Wednesday after a strike picket showed up at his Gatineau job site. (CBC) Workers in the industrial sector want more fixed work schedules, he said, while the employer wants the ability to shift workers — to a Saturday, for example — without having to pay overtime.

Salaries are believed to be the main stumbling block in the residential construction sector.

Quebec Labour Minister Dominique Vien said the province could decide to table back-to-work legislation if necessary.

The government said the 10-day work stoppage in 2013 resulted in a 1.1 per cent hit to Quebec's gross domestic product.