Advice please with block and beam

[Hugh Blackwood]

Morning folks. I have a garage with block and beam flat roof. This was "rubbered" last year and a ballustrade put around it. I would like to lay slabs on it to use as a patio (because my house is built into the hillside there is level access from the rear).
My question is how much weight will it take? I have a load of secondhand Sandstone slabs I was planning on lating on top of "envirofelt" and then use some rubber disk things (so no screed/mortar involved). Obviously slabs are quite heavy and I don't want the wife having a terrible accident....mwah, ha,ha
The span is about 4 meters maximum. Any help appreciated.

 

[George_engineer]

Do you have the original construction drawings or what B&B sizes and spacing was used? A local engineer could do a short document review and advise on the safe load.

It was either designed to carry some sort of useful load, or it wasn't. If it wasn't then you'll need to strengthen it.

 

[jeds]

As above, to answer the question with certainty we'd need details of the original floor. My guess is the floor will be capable of a certain capacity. Have a look at promenade tiles rather than slabs. You'd probably be ok with those.

 

[robinbanks]

Tell us the exact size of the beams, and the pattern to which they are laid out..

 

[Hugh Blackwood]

Thankyou all for your input....I will measure up and repost with more detail