I have a timber-framed house and trying to find out if I can get the loft extended. I know that I need to check whether the foundations can cope with an additional floor of living space (it's a raft foundation), but before I get that checked, I need to know what options I have.

As it is timber framed, it's not as easy as just pushing some girders through to rest on the supporting walls.

One small chat I had with someone (their name was on the loft trusses) is that they could change the trusses to Attic Trusses (?) but in the process this would mean that the upstairs rooms would all loose their ceilings. Not good.

When I lived in an older house, over the years the loft had been hacked about with new supports worked in to make the usable space larger. Can't this be done with modern trusses without removing them completely?

There was a company selling some kind of extendable aluminium girders that I saw on a TV programme. I'm pretty sure that they were OK with a timber framed house.

You would still need to cut out the trusses though, and it is those that support the ceiling. Remember that modern trusses do two things: support the tiles on the outside and keep the ceiling below. So don't think of it as a loft floor, but being on top of the ceiling of the floor below. Subtlr but important difference. That's why if you change the trusses you would need to retile the roof and replace all the ceilings. Not cheap!

Do you have no other options? Like a single storey section of the house? Connected garage?

Hi - Timber framed houses are actually very easy to manipulate - add bits, change bits etc. BUT you need a proper timber framed engineer to work out what needs doing, due to the stress calculations on the rest of the frame. Most "normal" builders won't be qualified to do this kind of work.

In reality, the roof can just be picked off and a whole new one put on, with the correct supports for usage. But that means that you will also lose the ceilings of the top floor. Depends whether the rework is worth the final target.

what factors should i consider when contructing a pitched timber roof?