I am renovating a house and have to remove retrofit insulation from the cavity as there is damp. I am, also, upgrading the wall ties so was thinking I could put PIR in the cavity and since I want to clad with brick slips or render could put some external wall insulation (either EPS or PIR) on...
I have run calculations using a joist calculator which have said that 72x170 C24 would be sufficient for my 4.3m span but I cannot find this timber locally so I am trying to work out if 47x175 C24 doubled could be an alternative? The calculator said 47x175 C24 would be okay for 4m so doubled...