Hi, am new to the forum, and need some advice. I'm doing an extension that forms three, one bed flats, with attic bedroom. Plans are passed, and I'm starting the footings mid March. My problem comes in the construction the architect has chosen, and his justifications. Although flats are an extension, new build regulations apply. He has done it in timber frame, as he says this is the only way of achieving SAP figures, especially as I don't want to run gas supplies. My issue is, most frame companies don't do extensions, and those that do are very expensive in my area. He's also used 100mmx50mm timbers that no one seems happy to use. Question is, how much, if any, problem will I have reverting to brick and block?