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The Width Is the Span. The Length Is Just More Bays.
People describe an arena by both numbers, 70 by 160, and assume the big one is the hard part. It is not. The 160 is simply repeated bays down the length, and adding bays adds cost in a predictable straight line. The 70 is the problem, because that is the distance your roof has to cross with nothing underneath it.
Get the width right in your head first and the rest of the order follows from it. Two arenas of wildly different total area can be near identical timber jobs per bay if they share a width, and two arenas of the same square footage can be completely different jobs if one is narrow and long and the other is wide and short.
It also means the cheapest change available to you, early on, is narrowing the arena. Going from 80 ft to 70 ft is not a 12 percent saving on the roof structure. It is considerably more, because span drives member size non-linearly, and member size drives both the board footage and whether the sections are still ones a mill can cut.
Standard Footprints
Common Arena Sizes and What They Ask For
These are the footprints that come up most often. Dressage courts are fixed by competition rules. Everything else is convention rather than regulation, so there is room to move if the span is pushing your budget.
| Footprint | Clear Span | Typical Use |
|---|---|---|
| 60 x 120 ft | 60 ft | Private and small training arenas. The smallest footprint most riders find workable for flatwork. |
| 20 x 40 m | 66 ft | Small dressage court, the international standard for lower level tests. 66 x 131 ft in feet. |
| 70 x 160 ft | 70 ft | The common working arena. Enough room for a jump line or a full flatwork pattern. |
| 20 x 60 m | 66 ft | Standard dressage court, required from the mid levels up. 66 x 197 ft in feet. |
| 80 x 200 ft | 80 ft | Full size riding and training arena. Typical for boarding and lesson facilities. |
| 100 x 200 ft | 100 ft | Jumping, reining and roping. Beyond the span most timber roofs are built to cover. |
Clear span shown is the arena width. Your structure spans slightly further than the riding surface itself once wall construction is accounted for.
Specifying It
Grade and Heart Center
Our standard is No. 1 Structural, WCLIB graded, and for the great majority of arena work that is the correct specification. It carries the published design values your engineer is working from and it looks the part.
Select Structural is available and adds 30 percent to the stacked rate. It is worth it where members are both highly visible and highly stressed. On an arena that is usually a short list, and spending the upgrade across the whole package is rarely the best use of the budget.
Free of Heart Center is the other specification that comes up. Excluding the pith from a member reduces how much it checks and twists as it dries, which matters on exposed columns people walk past every day. We can supply FOH up to 12x12, at no charge below 10x10 and $0.50 per board foot from 10x10 through 12x12. Above 12x12 it is not available, because a section that large cannot be cut free of heart from the logs that produce it.
The practical read: ask for FOH on the columns you will see, take standard on everything in the roof, and put the saving into length instead.
Long members cost more per board foot but remove splices, and a splice is hardware, labor and a detail your engineer has to design. On arena work the longer piece is often the cheaper answer once the whole job is counted. Run it both ways before assuming otherwise.
Scope
What an Arena Needs That We Do Not Sell
We mill heavy structural timber, 6x6 and up. A complete arena needs several things that fall outside that, and it is better to know now than to find out when the order arrives short.
Kickwall boards. The solid wall around the riding surface is usually 2 inch or 3 inch material, not timber. Different product, normally sourced locally and more cheaply than we could ship it.
Anything in ground contact. Douglas Fir is not naturally rot resistant and should not be buried. Columns want a pier or footing with a standoff bracket so they start above grade. Where something must go in the ground, that is pressure treated material and we do not mill it.
Footing and base. The sand, the drainage, the compacted base. Nothing to do with a mill, and more decisive for how the arena rides than any timber choice you make.
Roofing, hardware and erection. Metal roofing and connection hardware come from elsewhere, though a build kit from us can arrive with the hardware included and the members prepared. Construction itself goes to your contractor, or to our partner company Svensen Builders in Western Washington.