Indoor Arena Interior - Built with 5' high sloped kickboards, strong glue-laminated posts and all of the proper wall & truss bracing. When building kick-wall, we recommend to have it slanted as shown in this image. Here, we have the bottom of kickboard wall at least 12" away from the posts. This type of kickboard construction helps to keep horse farther away from the wall, which in turn, helps to protect horse and the rider from injuries.
Recommendation: When indoor arenas are used for jumping, headroom clearance on inside of the indoor must be at least 16' or higher. When it comes to roof trusses, it's advisbale to order trusses slightly stronger than what local codes require of you. If you have 35 PSF ground snow load in your area, upgrade trusses to 40 PSF. With unpredicatable weather, you just never know how much snow you might get in the future.