bracing for casting platform

[alumacraft716]

i have 3/4 in. cabinet type plywood that i put over the front two bench seats for my platform. there is about a 3 foot gap between the benches. do i need to put a frame or some kind of bracing to support that? thanks in advance

 

[270Handiman]

My initial thought is "yes!". It may seem strong enough now, but it will develop a "bow" over time, if nothing else. I would brace it.

 

[Waterwings]

My initial thought is "yes!". It may seem strong enough now, but it will develop a "bow" over time, if nothing else. I would brace it.

Concur 100% 8)

 

[Toney100]

3/4" plywood should span 2' o.c max ,just as in house building. Also that is under the condition u have the grain running the correct way (perpendicular to the joist or the "supports"). Run your supports on edge that will be the strongest. 1 guy I saw ran 2 2by4 on edge w a block screwed to the benches it looked to be solid and easy to do. That is if your deck is to be that height. Good luck!!!

 

[alumacraft716]

i would prefer not to have it become any higher than it already is. is there any bracing that wouldnt raise the height

 

[Toney100]

I dont mean to put it on top of the benches. The block would be screwed to the side of the bench flush say a 16"to20" 2by4 block. Then when u run your 2by4 on edge "like a deck joist" u will be able to screw into the side of the block everything would be flush with the benches. If your benches have more room under the 2by4 I would put another block under the supports so u are not just relying on the screws to hold the deck up. If u do do this it would then be very easy to then put 2 blocks in between your 3' span wherever and create a hatch for storage and also to air out when not in use. Another idea is eliminate the block and just use a joist hanger. Pics would help post some if u can.