Western Building Systems is insisting there were no "short cuts or penny pinching" involved in its school construction projects.
Work is underway, after assessments of the company's 42 schools were completed yesterday - with more than half needing some form of remedial work.
19 out of the 42 schools built by Western Building Systems are having safety measures like fencing and protective decking installed.
19 other schools were given the all clear following assessments.
Four schools will partially re-open.
Minister for Education Joe McHugh says safety measures should be in place by Monday.
Orla Hegarty from UCD's School of Architecture says there could be a number of reasons for the current issues.
"The Rapid Build programme started from about 2008/2009 when population pressures in new areas particularly meant that there was a big demand for school places," said Ms Hegarty.
"But unfortunately the weaknesses in that were that a lot of things were outsourced and there was enormous time pressure put on people, often unrealistically.
"Also, the system was set up to favour the cheapest bidder."
For its part Western Building systems says it has always had high standards and never engages in "shorts cuts or penny pinching" and it has criticised the department for giving the impression at the start of the controversy that all 42 schools could be facing closure.
Digital Desk
