When my Girlfriend moved in, we added her couches to the theater room and moved the theater chairs back. I knew I needed a riser and it would take me several months to build it. To make the building of the riser easier, I used simple 2 x 6 lumber for the frame and filled it with cheap insulation to help soak up some sound. I topped it off with 3/4″ OSB to make sure I had enough strength for the 2″ lip I wanted.
I framed up the riser just like I would for building a wall with 16″ spacing and a top and bottom support beam. This way, I could use standard wall insulation, and I was sure it would be very strong to hold chairs and people. To attach the OSB sheets, I cut them to size and glued and screwed them to the boards so there would be no creaking for years to come.
I knew I would not be able to match the carpet to what we had there already so I went to a carpet store and bought a remnant that was completely different. For the trim, I actually used 1 x 6 select or better lumber. I tried to find the trim with the least knots and issues and you really can’t tell that is is not “trim quality.” To add just a bit more detail I also decided to attach some corner-round trim at the bottom. I stained it all with Min-wax gunstock oil stain and poly on top of that. The color is nice but a little more on the orange side than I wanted but I think it looks ok.