Backyard rink board height
A board has to be taller than the water at the deepest point, with some room left above it. On level ground that is easy. On a slope the low side needs a taller board than the high side, and that is usually what decides which lumber to buy.
The rule
board height = water depth at that spot + room above the water
Water depth at a spot is the depth you want at the high end plus however much lower the ground is there. The room above the water is up to you. The calculator defaults to 2 in.
The Snipers Edge hockey blog works the same idea from the other side. With 24 in boards and 3 in of ice, it says, "your elevation change could not be any greater than 21" from low point to high point or the water will literally flow over the edge." Their math leaves no room above the water. Leaving some, as the table below does, shrinks the drop a board can cover.
How much ground drop each board covers
With 3 in of water at the high end and 2 in of board above the water line, a board of height H covers a drop of H minus 5 in, from the high corner to the low one. Lumber sizes are actual heights.
| Board | Actual height | Largest drop it covers |
|---|---|---|
| 2x6 | 5.5 in | 0.50 in |
| 2x8 | 7.25 in | 2.25 in |
| 2x10 | 9.25 in | 4.25 in |
| 2x12 | 11.25 in | 6.25 in |
| 16 in | 16 in | 11 in |
| 24 in | 24 in | 19 in |
A 2x6 only just clears 3 in of water plus 2 in above it, so it suits level ground or the high side of a slope.
Standard height for a level yard
I did not find one agreed minimum. The sources I opened treat height as a tradeoff. Snipers Edge says many boards are knee high, at 24 in, and that lower boards let the puck bounce out of play more often and make it easier for a kid to trip over them. It also says taller boards keep the puck in and let kids practice lifting it off the boards, but are harder for younger skaters to get over.
If you only skate and do not shoot pucks, the board mainly has to hold the water, so clearing it by a few inches is the minimum. If pucks are involved, taller boards help: Snipers Edge calls 24 in "knee high" and common, and taller boards also leave more room for a slope. Pick the height first, then see how big a drop it leaves you.
On a slope
Pwice, a rink kit maker, says to install taller boards on the downhill side, and describes a rink built on a 12 in slope with 2x12 boards on the low side and 2x6 boards on the high side. It also says a slope of more than 6 to 8 in causes uneven ice depth. Iron Sleek, another kit maker, lists a site that is level within 12 in as a requirement for its kits.
By this table, a 2x12 covers a 6 in drop at 3 in of water with 2 in of room above it, so Pwice's 12 in slope with a 2x12 low side would leave no room above the water. Their rink may have been shallower, or the ground was built up. Your numbers will differ, so measure the four corners and let the calculator give a height for each side. The measuring guide has the steps. For what to do when the low side needs more than a 2x12, see building a rink on a slope.
Taller boards also need a bigger liner. The liner size chart shows by how much.