I've got an existing concrete structure which is attached to a wooden house but they both share the same concrete floor. My client wants to convert the wooden house into concrete as well which means I will have to place new columns against existing columns. Can anyone tell me what is the best way to make that connection between existing column, beam and new column, beam?

Thanks

You pin the columns together with steel rods. This is done by drilling the existing column, cementing the rods in place then building the new column and fitting /cementing the rods into the new column