Opening up a ceiling void??

[amgill2]

Hello, I would like to remove a ceiling and its supporting beams to open up a roof void above a room, but I don't know whether the beams have any structural role. The void is above the 1st floor room of a two-storey rear extension (in a victorian terraced house). The extension is shared with my neighbour, with a party wall between the two sides. My roof slopes away from the party wall down to the exterior wall, leaving a triangular roof void about 4 feet high and 10 feet across above the room. The horizontal beams that the ceiling is pinned to are about 6cm x 6cm. They are attached on one side to the party wall, and on the other side they are pinned to the main sloping roof beams, near to the exterior wall (but not actually attached to the wall). Hope that makes sense. The answer may be that I need to check with a structural engineer, but any views appreciated! Thanks, Andrew

 

[JohnD]

"Ceiling beams" have the purpose of preventing the side walls being pushed apart.

If you put three playing cards, or books, in a "house roof" shape, the friction of the top two on the bottom one stops the top ones spreading apart.

If you remove the horizontal constraint, the roof tends to push outwards at the sides. The house then collapses outwards.

This sometimes happens in fires.

 

[amgill2]

Thanks JohnD - I see your point. I guess the ceiling will have to stay where it is.

 

[Nige F]

what`s 6cm in Victorian English .a structural engineer will tell you if you can raise the height /position of the cross members, which may be a good compromise

 

[amgill2]

Just in case anyone else ever contemplates this, I've been told by a structural engineer that the ceiling beams form a triangle with the joists and stop the joists applying outward pressure on the exterior wall (and potentially the wall bulging out). So if I want to remove the ceiling, I would need to insert a steel beam along the length of the exterior wall, fixed at each end, to which I can pin the joists.