For a flat warm roof on an extension with a parapet all around, my block later is out by 30mm on one corner of the building and 10mm on the other side. Not happy one bit but he's been paid and gone!
2 options I have now is to shutter this out and fill with either sand and cement or concrete with small chippings or concrete sand. Or I can pack the joists up with shims and build up the mortar bed for setting my insulated blocks between the joists. I already have bags of plastic shims from 1mm up to 10mm which will be perfect under the joists for getting them level. These would save work cutting timer shims but are they acceptable for under joists.
2 options I have now is to shutter this out and fill with either sand and cement or concrete with small chippings or concrete sand. Or I can pack the joists up with shims and build up the mortar bed for setting my insulated blocks between the joists. I already have bags of plastic shims from 1mm up to 10mm which will be perfect under the joists for getting them level. These would save work cutting timer shims but are they acceptable for under joists.
