I have looked at a building with stay in place tin pan floor joists that
was building approx. 1930. I have the original drawings however the
drawings state only 12" T.P.J. + 2" slab. No reinforcement for joists is
given. I was called in to look at it because there is a 1" deflection in
the floor over a span of 24' without any significant live loading. The
condition of the floor slab is terrible and they want to level and smooth
it with DuraCap a gypcrete product.
They removed a 1" thick layer of what looked like solid asphalt or tar.
This stuff weighed about 13 psf. Never seen that before. Went up in flames
after 5 seconds. Does anybody know what this stuff is? There was linoleum
As far as the structure goes I am at a bit of a loss as too how to check
this floor and to why there is such a large built in deflection without any
significant live loads...Apart from the old standby...it was built that way.
I am planning to remove at bit of the pan at the quarter point and chip the
concrete off to see what the bottom bars are. I will also inspect the
concrete between the forms at the bottom of the ribs to check for any
cracks. I can also do some inpact tests on the slab to check for concrete
strengths although I don't know how accurate these will be on a 2" thick slab.
Any thoughts or related experiences.
David Handy, P.Eng.