Weight of Reclaimed Spanish Tile

[jdgengineer]

I have a question that I was hoping everyone could help me with. On one of our projects we are using a spanish tile roof that will be made using reclaimed double-barrel tiles (i.e. no S-tiles). Per ASCE 7 the assumed dead weight of these tiles is 19 PSF. However, every tile manufacturer we've contacted (3 of them) have told us that these tiles are in the installed weight of 12-13 PSF (including overlap and mortar). Does anyone know why ASCE 7 uses 19 PSF for spanish tile? It seems like its on the high side. It's what we used in our structural calculations but are now being challenged by our architect for overbuilding.

 

[JedClampett]

I'm torn between my natural inclination to tell an architect to stick to his knitting and giving you help. But I've seen the same thing. The manufacturer's values are in the asme ballpark as you stated. And AISC uses 9 to 14 psf.
Maybe the ASCE number includes the underlayment and plywood. Or is it possible that ASCE is giving a number for the staged tiles (during construction) to be safe? Even though they spread the loads out, they are in heavy little packages.

 

[hawkaz]

Modern tile can be lighter than old tile. If you are using re-claimed tile, stick with your number.

 

[MiketheEngineer]

How about weighing a sample or two or three?? and then add in your other dead loads - like plywood, rafters, insulation, ceiling, etc!!

As engineers we are allowed to make "informed" decisions!!

 

[concretemasonry]

I am just guessing that the assumed weight shown in ASCE is old very conservative to cover all different styles. I have no idea of the definition of "Spanish tile". In the past, there was a wide range of weights and patterns plus, often the tiles were extruded in a very thick profile to account for the firing distortion in the older facilities.

Modern tile can be extruded thinner since the controlled firing conditions do not cause as much distortion.

The method of sampling and weighing the subject tiles to be used is the only logical way to go if the OP is signing off.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[jdgengineer]

Thanks for the help guys, I appreciate it.

 

[OHIOMatt]

We did a project a few years ago, where existing tiles were removed for some renovation work. New tiles were added. The contractor that removed the tiles actually weighed the old tiles as he removed them as the owner had a buyer in another area of the country and shipping costs were a concern. The tiles ended up weighing 20 to 23 psf.

Your number of 19 psf seems reasonable to me.

 

[ishvaaag]

In Spain, "roman" (curved) spanish tiles (without any layer of mortar, that must be separately added when existent as such) were listed between 40 to 60 kg/m2 (8.19 psf to 12.29 psf) following the case in NBE AE-88. I have not searched current code CTE but should be very similar on weight issues. Since 2 cm of mortar was (lately at least) using as bedding -or line fixity, average- for the tiles, and this adds in the order of other 40 kg/m2, the final weights should be between above 16.38 psf for new and above 20.49 psf for old or new but weightier tiles, mortar weight included.