When does an underground lot stand eight storeys high? When it’s at Montreal's West End superhospital.

The Charbonneau Commission heard some stunning testimony Friday detailing how the Lavalin construction firm allegedly manipulated rules to allow a cheaper above-ground facility to be built while the project specifically required an underground parking facility.

The project initially required 1,600 parking spaces in the Glen Yards, all but 150 of which were required to be below ground, as part of a parking facility which would have cost about $91 million.

But SNC-Lavalin was given an exemption to build only 1,270 spaces, all above-ground, giving them a $25 million advantage over competitors.

Other bidders were not informed that the MUHC would accept the lower-cost alternative parking solution.

The CDN-NDG borough wanted an underground parking lot, but as anyone can see driving past, the eight-storey parking lot now high above ground.

SNC-Lavalin went to the borough and said the reference point for the underground parking structure should be Decarie Blvd., and not St. Jacques St. which is much lower.

But the borough building code says the basement is calculated from the bottom of the wall of a building, so instead of calculating from St. Jacques, engineers calculated from Decarie Blvd, 500 metres from the garage.

The borough agreed to this redefinition and accepted that an eight-storey parking lot would be classified as an underground parking facility.

The extent of corrupt behaviour in awarding contracts for constructing the MUHC superhospital is the current focus of the Charbonneau Inquiry.

Investigators André Noel and Eric Desaulniers testified on Thursday and Friday as to how the MUHC stacked the cards in favour of SNC-Lavalin to win the contract to build the superhospital, and strongly encouraged another consortium to drop out.

Many people involved with awarding the $1.2 billion contract to SNC-Lavalin in 2010 now stand accused of corruption, fraud, money-laundering and many other crimes, chief among them former MUHC head Arthur Porter, his wife, and multiple senior executives from SNC-Lavalin.

Porter was later fired from his position and he left the country. He is currently in jail in Panama fighting extradition to Canada to face charges of leading a criminal conspiracy.

During their investigation, Noel and and Desaulniers met with 50 people and sifted through 1,500 documents pertaining to building the hospital.

The investigators say friendly contacts between personnel at the the MUHC and SNC-Lavalin began during the call for tenders period, and grew closer when St-Clair Armitage of the PPP consortium bought a house next door to Pierre Duhaime of SNC-Lavalin.

After a round of bids where quality as well as low-price were examined, SNC-Lavalin was initially behind in appraisals, but then the tenders were dropped and re-issued.

Noel and Desaulniers say notes and recommendations were later revised in order to favour SNC-Lavalin, allegedly at the urging of Porter and others.