Can you explain how the EU rules would stop the construction of social housing? As far as I can work out, the only issue the EU would have with it would be if it pushed Swedens debt ratio way up, above the agreed limits. But I think this could be argued as different to other sovereign debt as it creates assets that recover the debt, rather than just being pure expenditure.
EU laws regarding public procurement & competition would be one of the obstacles that would make an operation of similar size too expensive and complicated.