DWC table top material

(sorry for the double post thought i was in the right area when i first wrote this)

hello roll it up peeps. quick question
I have a 4'x8' flood table, i would like to place a top on it drill some holes for a net pot, drop some clones in it and grow that way.

i was thinking of using the 4'x8'x1/2" thick(maybe up to 1-1/2" thick) foam board sold at home depot. question is will it support the weight of 15 plants grown just for their tops. so maybe 18' tall.
if i add some lil 2 inch abs legs cut to length under neath to add strength to top would that help?

anyways if i am way off here what would you recommend or what materiel are you using?

here we go something like this http://www.homedepot.com/Building-Materials-Insulation-Rigid-Insulation/h_d1/N-5yc1vZ25ecodZbaxx/R-100320352/h_d2/ProductDisplay?catalogId=10053&langId=-1&storeId=10051#specifications

thanks a lot guys stay frosty!

update it worked. thats all

I've used it before. It WILL start sagging when the plants get bigger. Just run some 2x2 or something under it to keep it from bowing

A piece of plexiglass works great, just paint it black and/or white.

I eventually made mine out of plywood wrapped in panda film. I think I single handedly keep the panda film makers profitable. LOL