estate agent problem (Valencia)

Hi I am on final stage of a property purchase, in which the estate agents builder said there were no defects on building, So i viewed the property in Valencia, and it was fine including the flat roof just bit of internal celling plastering for Protected content .

I asked the estate agent for extension estimation and she said 4m is about 1,500 euros is this a fair price?

Deposit now has been paid, and now estate agents builder says the flat roof is dangerous and estate agent recommends not to buy the house. I asked them to find out roof pricing for the house 60 sq ft.

Has anyone else got any estimations?

Any advice appreciated

kind regards