In particular, lightweight blocks are needed to meet energy requirements because of their high thermal performance. But they do not comply with Part E because they do not prevent sound travelling through walls.
The consultation document on the changes to the energy regulations gives people the opportunity to change their response to comments previously made about Part L in the light of the draft changes to Part E.
The two documents will now be issued at the end of the year and will become law six months later.
One senior civil servant admitted that consultation on Part E could also be reopened because of revisions to the structural regulations in Part A