I have an old house and recently had some major work done to the plumbing in my upstairs bathroom. The drainage pipe was leaking and had to be replaced. Therefore the bathroom floor was ripped up in order to get to the pipes.
When putting the pipe that goes into the toilet back it sticks up higher that it originally did. Therefore I need to build up the area around the toilet about 4 inches, creating a throne effect. If I put in 2x4s and plywood to build it up, how do i attach the 2x4s to the concrete below? Also, how far apart should I space them?