Almost 900 faults were found in the £431m Scottish Parliament building during final inspections to identify snags, it has emerged.
It has also been revealed that the chamber beam which came loose may not be covered by defects liability.
A final check in February, before responsibility for repairs passed to the parliament, identified 890 snags.
Independent MSP Margo MacDonald said it had to be established whether the roof had been signed off and when.
The ceiling problem happened a fortnight after the contractor's liability period expired on 17 February.
A spokeswoman for the Scottish Parliament Corporate Body (SPCB) said Presiding Officer George Reid had made clear that the parliament and its lawyers would do everything possible to redeem costs to the public purse.
She added: "But it is too early to say whether defects liability cover applies or whether another route for recovery would be taken.
"Our priority is to get the chamber fixed first and we are receiving full co-operation from all the parties concerned.
"Investigations into the strut situation must be allowed to continue before conclusions can be drawn about liability."
For the past two weeks, MSPs have been holding the non-committee sessions of parliament in The Hub, near Edinburgh Castle.
Holyrood's debating chamber may be closed for business until mid-May after the oak beam swung loose over the heads of MSPs on 2 March.
A detailed update from structural engineers Arup of what went wrong with the beam said one of two bolts to secure the lower end was missing, while the other was broken and had damaged threads.
It said the damage would have been caused by the bolt becoming jammed and someone then trying to remove it, twisting the head off or coming close to doing so.
Speaking to BBC Scotland's The Politics Show, Ms MacDonald said: "Surely there was a planning supervisor's report done on that roof, surely someone signed off the roof.
"If the defects liabilities are now signed off, somebody must have inspected the roof - if they didn't then I want to know why."
Alan Ritchie, general secretary of the Union of Construction, Allied Trades and Technicians, said he would have expected a risk assessment of the beamed roof to have been carried out at the start and end of the contract.
He said: "Before MSPs or anyone else went into the building, I would have expected those checks to have been done, there must have been a risk assessment done at the start of the project."
He added: "I think it would be something that would take a few days, especially if you're going to get scaffolding in and go up there and check it."
The SPCB spokeswoman also stressed that many of the other snagging issues were relatively minor and included an unpainted lamppost and a concrete slab housing a tree which needed to be altered.