James Gurney

Building a couch riser

Hi folks, I'm planning to build a riser for my rear row of seating, and I'm looking for suggestions. A few searches seem to indicate several people have built risers, but I wasn't able to find specifics.

Anyway, the idea I have in my head is to use 2x10 topped with 3/4" ply. The 2x10 would run all around the outside, and also cross brace about every 18", so the frame will look kind of like this from above: (some imagination required):


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I'm a little worried that a fully loaded couch could have as much as 600lbs of people sitting on it. Is 3/4" ply sufficient to support that much weight? The couch has 4 feet, each of which would not have direct support from the 2x10 underneath.

To address this, I was thinking I might add 2x4 bracing as well, so it would look something like this :


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Is this overkill? I worry that maybe I'm overdoing things a bit and it's going to end up weighing so much it's impossible to move it into the basement (the basement is finished, so I don't want to build it down there).

Also, since I plan to cover it with carpet, I'd like to route the corners to get a nice smooth turn, which will prevent the carpet from looking nasty as it turns to go down the side. The problem is, you can't really route plywood, so I'm thinking of somehow working an inch or so of mdf into the top corner, so I can easily mould it. Anyone have any comments on that idea?

Thanks in advance,

James

Jay Mitchosky

Traditional framing is based on studs mounted 16" on center. Generally it is recommended that theater risers (and stages for that matter) are framed at 12" on center. 18" is too wide, and you certainly don't need to crisscross. I would suggest you glue and screw end to end.

For the deck standard practice is not one but THREE layers of plywood. First 3/4", then 1/2", then another 3/4". Each layer offsets the seams of the one below. You also sandwich a layer of 15 or 30 pound roofing felt between the layers so they don't creak when walked on. Everything is screwed down tight. Here's what it looks like when complete (the edges have been rounded over with a 1/2" router bit in preparation for carpet). You can view stages of construction on my site.

\"The computer had attained consciousness, only to reject it, claiming it was too unstable an operating system.\"

Jimi C

It will be enough. We have 1/2in plywood on a 10 ft high steel shelf at work with bracing every 18inches and it is holding thousands of pounds of merchandise and not bowing, bending or sagging at all. Not to mention the weight will be well distributed because of the sofa. Personally, i think your plan is overkill if anything.

James Gurney

Jimi - the couch actually has 4 feet, so the weight isn't evenly distributed.

Thanks for the info Jay. Your HT looks fantastic! It's interesting that you were able to succesfully round the plywood fairly easily by the look of it. I expected it would splinter more than that.. so at least I don't need to worry using mdf for the corners.

3 layers of plywood seems an awful lot. Is this to a specific building code? With studs every 12", I would have thought a single 3/4" sheet would be sufficient. The riser I'm building will be 6' x 4'8", so there will be only one seem in the ply.. As I said before, this is a finished basement, so I'm planning to build in the garage and then bring it down the stairs. I'm a little worried about it ending up weighing too much to move..

Jay Mitchosky

Painless. Only splinters at the ends so route with the grain first, then into the edge against the grain. Remember that it doesn't have to be a pristine finish as it will be covered with underlay and carpet.


Not code. Just designed to be rock solid so as not to reverberate like a big drum. That aside, think how spindly a riser with only a 3/4" deck would be. It would look ridiculous looked on edge. And the overhang (which should be about 2") would be subject to cracking with repeated use. Imagine what a stair step would look like with only a 3/4" deck.


Good luck. That will be a big challenge because of the weight and the awkward size. If you're worried about dust I feel your pain. Which is why I had Home Depot cut everything for me. Then it was a matter of putting it together. Drilling only left no dust. Particularly for the deck sections where they have a nice panel cutter (unless you already have a table saw). Regardless, your time is valuable and unless you have the proper equipment it's very convenient for your lumber provider to cut for you. Just triple check your measurements first!

\"The computer had attained consciousness, only to reject it, claiming it was too unstable an operating system.\"

James Gurney

Hm, hadn't actually planned to have any overhang - I was thinking of making it come right up to the edge. Although, doing it this way, I can make sure the 2x10 at the edge is directly under the legs of the couch.. to be absolutely certain of the support.

As far as constructing it, the local Home Depot does indeed have a panel cutter, so I can have them do most of the cutting. I do have enough tools to do it myself if needed. I guess the thing to do would be to prepare it in the garage, and then assemble it in the basement.

Actually, another question arises - where did you find the insulation you used? Is that a standard type I can also pick up at the Home Depot?

Jay Mitchosky

Just a box would frankly look kind of goofy. An overhang will present more of a finished look. Plus you could install rope lights to see the edge in the dark and avoid people falling off.


Absolutely. It would be a tremendous pain to try and haul a finished riser downstairs.


HD. Everything HD. I used basic insulation specified for inner walls and sound transmission. I think I went through 2 1/2 bags for the stage, riser, and counter. Get some paper masks and work gloves as well for working with it.

\"The computer had attained consciousness, only to reject it, claiming it was too unstable an operating system.\"

Andrew Stoakley

Quote:

Just a box would frankly look kind of goofy. An overhang will present more of a finished look. Plus you could install rope lights to see the edge in the dark and avoid people falling off.

I guess that depends on where your riser is going to be. I have a riser that is built directly into the back of the home theatre and I didn't bother overhanging the edges and with the comments I've received from people on the theatre, I'm happy with my decision . I was more afraid of people tripping on the lip and then smashing into my subwoofer . Anyway, Build you riser in the room that you are working in. Cut your lumber in the garage and assemble it in the final area. I used the standard wall practice for the riser with studs 16" on centre. 2x6's for the framing, and two layers of 3/4" construction grade plywood. The construction grade is a little cheaper here in Toronto and with the rough side down on the framing wall, the adhesive really sticks nicely! I filled the cavities with Roxul's Safe and Sound batting and screwed down the top layers with 2 1/2" decking screws. The riser is 9x5 and has a 3 person leather couch on top. Nothing moves, nothing shakes and nothing creaks when there are three people up there watching a flick.

Check out my pics to have a look.

Cheers,
Andrew

"Remember kids - no one cares about audio until they can't hear it."

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Jay Mitchosky

But if there are ropelights to illuminate the edge you wouldn't have to worry about it.

And don't forget steps as well depending on the height of your riser. Use the stairs in your house as a reference.

\"The computer had attained consciousness, only to reject it, claiming it was too unstable an operating system.\"