what is the process and costs for knocking down an internal wall in order to open up a room?

consult a local builder for a realistic quotation, an engeneer will be required to calculate the size of the rsj ( lintle) required, post it as a job and you will have a choice of trusted local tradesmen

As its structural you will need a structural Engineer, plus building regs. If your changing use of garage to habitable, you also need planning.

hello, your first step is to get a structural engineer or architect round to find out what RSJ ( rolled steel joist ) would need to be fitted to span the opening. once this is done knocking the wall down and fitting the RSJ is pretty straight forward but can be messy. Maybe two days work at max depending on the size of the wall. Please be aware though that the floor level in your garage maybe lower than the one in the rest of the house/kitchen as garage floor are not normally screeded. Hope this helps Joe Williams J.W Building Services