Hi Guys,
I'm doing some upgrades to our HT. I need to add a riser to the back row for another row of seats. I've built the frame and need to get the top on it this week. I was at HD tonight looking at plywood and saw 4x8 sheets of OSB marked down to $4.98/sheet. For some stupid reason, I can't remember the thickness, but it was probably around 1/2". I'll need four sheets to cover it. Has anyone else used OSB for a riser floor? My frame is very well built and has lots of cross-bracing for support. Everything will be screwed on with deck screws. The three seats that will be placed on top will weigh around 350-lbs empty. I know plywood will be much stronger and will still only cost me around $50. The money isn't the issue, it's just the good deal on the OSB.

My builder used OSB for all of the flooring in the house so that's what I used on the riser. However, half inch seems kind of thin. Make sure that yours is tung & grove and it will probably be for flooring. (I think mine was around 3/4" or 7/8".)

http://lh4.google.com/tllenah/RqyctjURlCI/AAAAAAAABYc/ihln9Vwg3JM/s800/Lights%20%26%20Shelf%20Opening%20008.jpg

Thanks, I'm going over to HD tomorrow to buy something. I'm pretty sure the OSD they had was for flooring. I'm one of those guys who built a theater in the basement and then left off some of the final touches...like the back row of seating. Mainly because I installed the pj too soon;) That was three years ago. I got motivated again a few months ago and have had three giant boxes in the garage since October.

BTW, that's a nice looking riser you have. Ours was a little time consuming for me to construct. I had to build around four columns that house speakers. Then, there were the double doors.

I used 5/8 OSB for my riser and stage. I doubled the riser.

http://pic50.picturetrail.com/VOL426/2023328/18486887/293369087.jpg

Thanks ba, I was thinking about doubling it as well if it turns out to be too thin. For $5 a sheet, it's still cheaper than plywood if I double it.

I'd think you'd be fine. My original build used 3/4" plywood and I had no problems with a single layer. I'd double up your 2 1/2" layers of OSB, just make sure you run one layer one way and one the other, for added strength.

Hi Jeff. The good thing about using 3/4' T&G OSB is that it fits together tight. Using 2 layers of 1/2" would be good and thick, but you may get some squeeks where the side edges are touching. If you do go with double 1/2" make sure you leave a gap between the sheets. An 8 penny nail should work. And don't skimp on the construction adhesive. And you may want to fill in between the joists with inslulation. Just a suggestion.

I used a double layer of 3/4" T&G sub-floor OSB that was glued and screwed. The construction adhesive stops any squeaks and filling with insulation helps keep your riser from sounding like a big drum.

I used a single layer of 3/4 T&G OSB screwed and glued with 16' on center joists. I have had not problems with it at all.

I put 29/32" plywood down fo the first layer on the riser, but used some of my plywood that was intended for the second layer on another project. Went back to Lowes to get more, but all the plywood the had was terrible. Bowed like you wouldn't believe with lots of voids, chips, etc. so I saved $10 and went with 5/8" OSB for the second layer. Wish I'd used that for the whole thing.

I just returned from HD. I bought the stuff that was marked down at my local store. It was $4.98/4x8 sheet. It was only 7/16", but for that price, I can double it. I also bought a roll of roofing felt to go between it and the studs.

This post raises a question (sorry to hijack)!

What is the preferred method of construction? So far I have 2X8 framing to be filled with sand. Once that is done what is next:


#1
3/4" plywood
roofing felt
3/4" plywood
liquid nails
joist

or

#2
3/4" plywood
liquid nails (green glue)
3/4" plywood
roofing felt
joist

Thanks,
Judson

I used 2x12's and filled it with R38 insullation. I pulled off the kraft paper facing so it would not have the possibility of noise.