Expert: Dan Griffin - 2/27/2008

Question
Hi . We are putting in an arcade room in an upstairs bonus room in our house. There will be six games total that each weigh about 250-300 pounds for a total of 3000lbs. max. The games will be sitting on a raised platform built in a L shape in one corner of the room. Each game has a footprint of about 28"x30" estimated. The floor was built with a 2 x 10 system using #2 Southern Yellow Pine on 16" centers. The home was built in 2004. Are you able to tell if the floor can support this kind of weight? or what is that standard/average weight per foot required in new home construction. Thanks for any advice. Leanne

Answer
Leanne,
You did a marvelous job detailing the conditions except for how far the existing joists are spanning.

The raised platform idea really helps because you are distributing the load over multiple joists.  2x10 YP on 16" centers can span 17 feet carrying a 40psf live load (non permanent things like you, the furniture, the games) and 10 psf dead load (the physical weight of materials- the wood joists, the flooring, the gypsum hanging on the ceiling below, etc).  Let's assume your game space is 17'x 5'= 75 SF times a 40psf live load = 3000pounds.  The platform will add to the dead load but make the live load larger.

It makes a substantial difference which way the joists are running in relation to the large dimension of your "L".  Having the loads close to the walls helps rather than being out in the middle of the floor.  You aare probably OK, but I am impressed that you know to be concerned.  If your span is over 17 feet, write back with a bit more information.  You can use the span calculator here:
<http://www.awc.org/calculators/span/reversecalc/reversecalc.asp?feet=&inches=0&species=Southern+Pine&member=Floor+Joist&deflectionlimit=L%2F360&spacing=16&liveload=40&snowload=-1&deadload=10&wet=No&incised=No&submit=Calculate+Span+Options#answer>

There is choice for maximum span at the bottom.