[Tom Gassner]

I would appreciate any help or links that anyone can provide. I am beginning building a new house and have a dedicated home theater in it.

I've been reading as much as I could trying to plan my construction and need some help with these two aspects. Any help would be greatly appreciated. Thanks

 

[cgblack]

Welcome Tom, I'm just down the road from you, so to speak, in Vacaville.


A couple of things to keep in mind with risers and prosceniums. You want them to be as solid as possible. I used two 3/4" sheets of plywood on top, and I would conider that the bare minimum. Many people sandwich a 1/2" layer in between two 3/4" layers. Depending on the geometry of your room, 2 x 8 or 2 x 10 pressure treated lumber is a good bet for the riser framing. This gives you a finished height of anywhere between 9 1/2" and 11 1/2" which is about as high as you want to go, unless you want to add steps.


The areas between the framing joists should be, at a minimum, over-stuffed with insulation to deaden any resonances. Many people, including myself, filled the gaps with playground sand.


Overhang the plywood by about 2" for a nice lip and add 1/2 round to the edge for a nice finish. You can then run a row of rope lights underneath the overhang for a very professional looking finish. If you are going to use 120V rope lights, installing an outlet at one end of the riser is a good idea.


Cover the riser with some nice thick underpad and carpet and you're all set.


The proscenium stage should be of similar construction, although you may or may not want to carpet it. Usually the front speaker would rest on the proscenium stage, so again, solid is the key. The dimension are very much driven by the geometry of the room, projector, planned seating layout, etc.


In my case, I have a very narrow, high stage (16" deep, 24" high), for a very specific purpose. Since it is so high, I will probably not be filling it with sand, just stuffing it full of insulation.


If you can be a bit more specific about what you are looking for information-wise, we can probably provide better answers.

 

[Tom Gassner]

Thanks for the quick reply. I'm not sure what I want. I'm having the room built 12' x 22' . The entrance is on the back wall to one side. I had planned on having the seating to one side oposite the entrance. There will be two rows of seating ;one of them will be on a riser. If anyone can suggest sizes

based on this info I would greatly appreciate it.

 

[controlit]

You may want to fill the stage with sand......


Mark

 

[usabrian]

Quote:

You may want to fill the stage with sand......

At which point it ceases to be a stage and becomes a permanent foundation! Thats just too permanent for me.


Brian

 

[Dennis Erskine]

If you're going to the trouble and expense of putting in a stage, and you're putting your sub-woofer on it, and you don't have a structural issue, then fill it with sand. It would be a shame to potentially diminish the value of your investment in your theater for $50-$60 in play sand.


Should you ever need to remove your theater, shoveling sand, I think, is easier than chipping away at a concrete foundation. Just ask Mark

 

[Strike Attack]

CGBlack,


Just wanted to let you know that I followed your instructions on building my riser and it is working out beautifully so far ... The builder at home depot said to lay some plastic down under the riser before you frame it (something to do with the concrete breathing), but I decided to seal it with Drylok instead. I am using blown cellulose for inside the riser. Thanks for the great info.

 

[scott jensen]

If you are starting the build...why not have the riser and stage built of concrete...while the foundation is being poured...that is presuming you are doing it on a concrete floor. The only downside is that if you sell the house, the new owner is restricted in the use of that room.

I did this with a basement HT that I dug and the rear seats are 14" higher...and its concrete.

My HT is about 12x20.

Scott

 

[CV63]

Quote:

If you are starting the build...why not have the riser and stage built of concrete...while the foundation is being poured...

One issue with this as far as the riser is concerned, is the loss of tactile feel you get with a wooden riser. The concrete riser is too solid and dead. The wooden versions allow you to really feel the bass during the movie.


I have carpet over concrete in my first row and carpet over a riser (built as above) in the second. Major difference in the tactile feel of bass when sitting in the second row. Plus no issues of the riser being permanent. Although its pretty damn close when built as above.

 

[SJB]

How do you fasten 2x10 or 2x12 lumber to a concrete floor in order to build the platform? I can't imagine that I should toenail with concrete nails. Any thoughts?

 

[cgblack]

I used Liquid Nails Subfloor adhesive. Between that, and the weight of the lumber + sand, well over 1000 lbs., it's not going anywhere! Be sure to thoroughly clean the concrete first


If you're still concerned you could always fasten some pressure treated 2 x 4's with concrete nails, and then screw the joists to the side of them.


It would look something like this:


8

8

8

8

8

84444

CCCCCCCC


8 = 2 x 8 Pressure Treated

4 = 2 x 4 Pressure Treated

C = Concrete


I would still use the Liquid Nails underneath and between these to ensure there is no rattling. Use the Subfloor adhesive between the lumber and concrete and the Projects adhesive between the 2 x 8 and 2 x 4's.

 

[builty]

I took a rather different approach to a riser in my theatre, as I built it before discovering this wonderful forum.


I constructed 6 box sections approx 1.5 x 1 metre each. They are built from 18 mm MDF, as an open bottomed box with a central cross brace. I used very long screws very frequently along all edges.

3 of them are 250mm high, and the other 3 are 500mm high. When I got them inside my room I stood them on their ends and bolted them together, then laid them flat and carpeted them. They are quite solid, and can be packed up and taken to my next house if needed.

The largest unsupported distance is 1 metre X 750 mm, but it really has very little flex. The bass from my 3 subs (2 x 12", 1 X 15", 500 wrms total) really shakes it nicely, so I agree that timber is the way to go.

Total cost for the wood was A$450, which got me 2 levels (one with step) and a 3 metre square area.


My setup is probably less professional than the first suggestion but easier and less permanent. Depends on what is most important to you.

 

[usabrian]

That's actually a novel idea Builty, for people who dont want something so permanent. IMO, too many people in this forum build very permanent expensive rooms in houses that likely will not support the value you just put into it. Its good to be able to convert the room to a play room, game room or whatever if you ever want to move.


You are likely not going to get much return on a a home theater room in a house under $350-400K in my area. (about a 3,500 to 4,000 SF house)


Brian

 

[bloomis914]

Check out my detailed pics at my link below for my Proscenium/stage and 2nd row riser. I have received many compliments and I did it all myself, I didn't use sand....Just lots of insulation.

 

[Thomas Marshall]

Tom,


Be sure and build your back riser high enough. A while back there was a post asking about the mistakes you made when building an HT.


One key area for a major screw up was building the rear riser to low.


If you can, decide what seats your going to use and take measurements prior to deciding on the riser height. The general consensus regarding adequate height, if my memory serves me, was approximately 10 - 14 inches high.


I built mine 14 inches (2 - 7 inch steps) and it is perfect for my setup. People can sit up right in the front row and recline in the back row, and the view to the screen is still unobstructed from the back row.


Other considerations are the screen size and how high off the floor you mount it on the screen wall. Take your time and measure everything ahead of time.


I mocked up the whole thing ahead of time, I marked the screen height on the front wall and got some crates and 4x8 sheets of plywood, and jury rigged a rear riser to be sure it was high enough.


Also, do some searches on "Risers" and "Prosceniums" you will find tons of excellent data.


Good luck

 

[Strike Attack]

Quote:

If you're still concerned you could always fasten some pressure treated 2 x 4's with concrete nails, and then screw the joists to the side of them.

Thats basically what I did. I took some of the pressure treated leftovers from framing of the basement and used liquid nails to glue them next to the risers. Then I used an L bracked to screw it into the riser and power nailed the block into the conrete.


And yet ANOTHER THING you may want to do when you build the riser, is put some perpendicular spacers between the joists of the riser to make it even more stable.