How very odd.
As someone says, they look like cold-formed C-sections as used in mezz floors and so forth, but the flanges look thicker than the usual 2mm or so, by the looks of things. Any dims for this and the web (to get the latter, measure above and below the flange and subtract one from the other)?
Back to back they give each other increased lateral rigidity, ie better to resist twisting.
With section sizes, centres and spans, it would be possible to work out what load they can take - to use as a domestic floor, the live loading requirement would be substantially increased over that for a loft space. On first viewing, I would guess that they would probably work, with the joists being fixed into saddle hangers onto the top flange and thus sitting in the depth of the steels.
As someone says, they look like cold-formed C-sections as used in mezz floors and so forth, but the flanges look thicker than the usual 2mm or so, by the looks of things. Any dims for this and the web (to get the latter, measure above and below the flange and subtract one from the other)?
Back to back they give each other increased lateral rigidity, ie better to resist twisting.
With section sizes, centres and spans, it would be possible to work out what load they can take - to use as a domestic floor, the live loading requirement would be substantially increased over that for a loft space. On first viewing, I would guess that they would probably work, with the joists being fixed into saddle hangers onto the top flange and thus sitting in the depth of the steels.
