Question about Plywood For Building Grow Box

[hawken]

Hey guys, I just got back from the Home Depot, pricing out the lumber I will need for my grow box.

They were very helpful and went over a bunch of options with me, and he was an old guy (not some young punk )so I trusted his opinion. So now I am leaning away from the MDF that a lot of people use. (And I planned on using)

I told the employee that I was building a "Shed" that would be outside year round (Always in the rain, sun, wind etc.) and would need to be completely weather proof. That is basically the atmosphere I will be emulating inside with the watering and lights etc.

He strongly recommended "OSB" which from what I can find is: strands or wafers of aspen-poplar bonded together under heat and pressure using a waterproof phenolic resin adhesive or equivalent waterproof binder. Oriented strandboard (OSB) was developed in the late seventies.

Well, he said it is my best option for having a strong weatherproof box. (It looks ugly, but I can always pretty it up, but painting or some nice veneer etc.)

He said the MDF would need strong treating or else it would deform and lose strength being in a moist or humid environment.

Also he said to use the 8ft, 2" x 3" Pine SPF, as my frame rather than the 2" x 2" I have seen others use.

So now I have heard what the hardware guy has to say, and I would like to hear the GROWERS Point of view now. Maybe there are other factors involved

 

[Respect]

Do you plan on having it outside or inside?

 

[hawken]

I plan on having it inside. I just told him it would be outside, so he could tell me what plywood he thought was most suitable for high heats and wet humid temps etc.

 

[Respect]

Well I consider myself quite the handyman with my own little business. In buying wood (at Home Dept) I've found that you can get either pressurized or unpressurized. It sounds to me you talking about pressurized which is basically compressed wood in order to create a better seal in the wood. This is used for outside construction as it is water resistant. In your case I would go with the cheapest option, most likely unpressurized 2x3's not even 2x4's. 2x3's will be plenty strong and slightly cheaper. If your really concerned about the internal wood seal, a light coat of white paint creates a water/air tight seal on any wood.

 

[hawken]

The ones he recommended as the best, are the cheapest option as well. I think I'll go with 2x2 simply because I initially made my blueprint for that, and changing it now, will mess me up

He said for the base use something stronger if I want, so I might use the 2ft x 4ft cut of MDF as the base. That was my dimensions anyway, and that will keep it "bottom-heavy" to avoid tippage.

Heres the prices:
3/4 inch Plywood:
----------------------------
MDF: 24" x 24" (2ft x 2ft) = $ 5.48
24" x 48" (2ft x 4ft) = $10.95
48" x 96" (4ft x 8ft) = $27.47


OSB: 48" x 96" (4ft x 8ft) = $ 6.87


8ft Frame:
----------------------------
Pine SPF: 2" x 3" = $1.78

or

Spruce: 2" x 2" = $2.57

or

Fir: 2" x 2" = $8.80

 

[Respect]

sounds great. 2x2 is even cheaper than 2x3 and will be plenty strong. I bet he advised the thicker base because it will be slightly heavier. It's not a bad idea at all.