Detection of metal or timber joist?

[fholler]

Hi
2 years ago we knocked a stud wall between our kitchen and living room areas to open up the space. Kitchen is about 3m long and living room 6m. We occupy the ground floor of a 3-storey Victorian converted house in England.
The builders said at that time that they had definitely seen a girder or joist (not sure if there is a difference) above the ceiling and halfway down the length of the living room and therefore we didn't need a new one. This didn't surprise me as the living room was extended about 60 years ago like all other houses on the streets so they must have added some sort of reinforcement at that time.
However, rather stupidly I did not check this for myself and relied on the honesty of the builders. The house hasn't moved since, but it frustrates me more and more not to know for sure. Is there a way to detect a girder without opening up the ceiling? Like something like this:
http://www.amazon.co.uk/Zircon-Z62291-Multiscanner-i520-Onestep/dp/B001ACRPKK/ref=pd_cp_diy_2
Otherwise, what would you advise?
Many thanks
Fholler

 

[jeds]

That scanner won't tell you anything useful. There are too many other things in the ceiling that might trigger a false reading. I find a strong magnet the most useful thing for picking up steel and metal in ceilings and walls.

 

[theprinceofdarkness]

How about lifting a floor board or two? Ceiling joists tend to go across the shortest dimension of a room, so the upstairs floor boards will be laid at right angles to them. So if the floorboards run house front to back, the joists run house side to side, i.e. go from wall to wall, so if there is a "beam" from side to side it would be to support an internal wall. If the floor boards run side to side, then the joists run front to back and a beam would be needed where they would have sat on the downstairs internal wall.
Frank