Final approval has been given by Calderdale councillors for a huge salt barn, which will be the authority’s biggest building.

Full Council agreed on Wednesday night to approve the preferred option of a 10,000 tonne weatherproof grit store at the Ainleys Depot at Elland.

They also agreed a maximum sum of £1.1 million to be included in the council’s Capital Programme, to be funded by prudential borrowing, to pay for it – and the decision has remained contentious to the end.

The council’s Place Scrutiny Board chair Coun Steven Leigh has expressed doubt it will cover its costs over an estimated 25-year lifespan and when the scrutiny board last met strongly argued his case, meeting an equally firmly rebuttal from the council’s Assistant Director for Strategic Infrastructure Steven Lee.

Councillor Leigh’s case argued a bigger barn, up to 18,000 tonnes, would make the desirable project viable but Mr Lee said that scale brought into play issues such as increased rateable value that affected cost and his department’s savings figures were correct.

At Full Council Coun Leigh (Con, Ryburn) continued to voice his concerns about the scheme – not the principle, but whether was was proposed would fully meet need and cover costs.

And at the end of the expected 25-year life of what officers say would be the council’s biggest building there would be no legacy asset.

“There’s no political fire and brimstone, it is simply that I believe the economic case for the money to be spent on this doesn’t make any sense,” he said.

Coun Leigh said he wanted to know if the stocks level would be enough to cater for a very severe winter and would there be difficulty getting top-up supplies.

Coun James Baker (Lib Dem, Warley) said there was more to the proposal – left stockpiled in the open supplies wet salt leached into the water supply.

“It isn’t just about cost efficiency, though that is important, it’s also about environmental impact,” he said.

The council’s Deputy Leader Coun Barry Collins (Lab, Illingworth and Mixenden) said the scrutiny board considered the arguments and did not agree with Coun Leigh, releasing the decision for implementation.

At the earlier scrutiny board Coun Collins had said the cost of the barn had deliberately been pitched as a maximum and was likely to cost less and estimated savings from reducing grit wastage were likely to be greater than estimated.

Speaking at Full Council Coun Collins said: “Officers say with confidence it can be better than forecast, and that is what councillors agreed.”

Coun Leigh had raised doubts about capacity but Coun Collins said the council had restocked in last year’s hard winter and there were also plans for 2,000 tonnes of salt to be stored at Holme End in the upper Calder Valley and was trying to identifying land for another 3,000 tonnes to be stored in North Halifax.

Conservative group leader Coun Scott Benton said the salt barn proposal had been sitting around since 2010 when it would only have cost around £400,000.

His party as horrified the maths did not stack up and Coun Leigh had been doing his duty at scrutiny board. They supported the salt barn but not necessarily the way Labour had gone about it.

“After eight years we are not clear it offers best value for taxpayers,” he said.

But Council Leader Coun Tim Swift (Lab, Town) said: “The course put forward is careful and prudent – this is the right and prudent way forward.”

Caption guidance – The Salt Barn will be built at Calderdale Council’s Ainleys Depot at Elland. Picture: Google Street View