I recently inherited my late fathers house. Late Tudor farmhouse and a big old barn of a place (no pun intended). Listed G2. Timber framed, brick infill to the ground floor, wattle/daub or similar to the 1st floor, peg tiled roof. The exterior is rendered & painted, timbers are exposed throughout. All timbers appear to be oak and in good condition mainly. Over the last few days I've had the chance to have a good look around and what I see dismays me greatly. The wiring, plumbing & ch have all been completely renewed in the last 10 years and there are no known problems with these. However, I can't find any other aspect of the old place that does not need major attention. Most of the problems I know how to deal with, but one in particular needs professional advice I feel. The main rooms on the ground floor are about 25ft square. The ceilings are supported by 12" x 12" beams in a + arrangement. The cross is central to each room and formed by a single timber span with the 2 'arms' double morticed/tenoned to that single span. Joists of 9"x6" are morticed/tenoned to the 2 arms at about 18" centres. A very substantial structure. In one room only the single span is bowed downwards by about 3" and this is immediately noticeable. Equally worrying is that the tenons of the 'arms' have pulled out by at least an inch on each side. I presume this is a result of the main timber bowing. As you might imagine this worries me greatly as a failure of these timbers could be catastrophic. To the best of my knowledge this problem has arisen quite recently, certainly within the last 20 years. I could jack up the ceiling beams and put a 12x12 oak prop beneath the centre of the cross. This would effectively destroy the appearance of a lovely room. I would be more inclined to jack the structure up beyond level and then secure the 2 arms together using a substantial metal strap or straps. I'm worried about what effects any jacking operation might have upon other parts of the structure. Thus I feel expert advice is needed. Anyone know where I can ask for such advice please?