How to Build a Mortise Fence

Mortise fences, sometimes known as mortise and tenon fences, are a type of rustic or informal fencing that generally act as a boundary marker or are installed for ornamental purposes. There are a handful of possible mortise variations, including side-by-side rustic joints, where the ends of the rails overlap in the mortise, as well as a style where rails made from 2-by-4s have half-laps, or notches, cut in at the ends in order to fit the rail ends together inside the post. Regardless of the various methods of fitting rails together inside the posts, mortise fence construction basics are similar.

Posts
Drill and small spade or Forstner bit
Hammer
Chisel
Post hole digger
Shovel
Level
Gravel or other backfill
Saw
Rails
Nails, if desired

Instructions

- 1
  Cut mortises in to the posts. Lay out the holes where they will appear on both sides of the post. Drill overlapping holes using a small spade bit or Forstner bit. If the rails will be placed into the same mortise that penetrates the entire post. Drill holes from both sides of the post to prevent splintering.
- 2
  Chisel the mortises using a hammer and sharp chisel in order to clean the hole and make square corners. Clear the mortises to the layout lines and make the sides square to the post surface.
- 3
  Dig holes for the posts. The distance between the holes should depend on the length of the rail. Do not forget to account for overlapping rails, if that will be the method used. For example, if the rails are 12 feet long and will overlap through the posts, the distance between posts should be closer to 11 or 11-1/2 feet, depending on the planned overlap.
- 4
  Place the posts in the holes. Make sure that the posts are pointing in the correct direction and are set at the correct height.
- 5
  Backfill the post holes most of the way with gravel or another suitable backfill material. Use the level to check for plumb regularly and maintain the correct alignment.
- 6
  Cut the ends of the rails. Make the ends tapering so that rail ends will fit together in the mortises and overlap. Alternatively, the ends can be cut so that one rail end has an upper block removed and its mate has the lower block removed so that they fit together snuggly within the post.
- 7
  Slid mating rails into each mortise. Remove small amounts of additional wood from mortises and rail ends as needed to fit them together.
- 8
  Pound a nail through the posts at each mortise to hold the rails in place. This is not necessary, but may keep the rails from sliding out of the mortises.
- 9
  Finish backfilling the holes so that the posts are firmly set and re-vegetate around the posts as desired.

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