Notch Types

Part of Permanent Shelter

The corner notch is what turns a pile of logs into a locked, self-supporting structure. A well-cut notch resists lateral forces, sheds water, and tightens as the wood dries. A poorly cut notch lets in wind, collects rain, and eventually rots out your corners. This guide covers the four main notch types from simplest to most advanced, with step-by-step cutting instructions for each.

Tools You Need

Before cutting any notch, gather these:

• Scribe (log compass) — two pointed legs joined at a hinge, like a large drafting compass. You can make one from two sticks and a bolt, or two nails driven through a flat stick at a fixed distance.
• Hatchet or hand axe — for rough removal of wood in the notch.
• Chisel and mallet — for cleaning up notch surfaces.
• Crosscut saw — for making relief cuts in deeper notches.
• Pencil or charcoal — for marking lines on the log.

Scribing: The Universal First Step

Every notch begins with scribing — transferring the profile of the lower log onto the upper log so the two fit together precisely.

1. Position the upper log on top of the lower log at the corner, resting in roughly the right spot.
2. Set your scribe to the widest gap between the two logs at the notch point.
3. Run the scribe along the surface of the lower log. One leg rides the lower log’s curve; the other leg draws that curve onto the upper log.
4. Keep the scribe vertical at all times — tilting it distorts the transferred profile.
5. The scribed line on the upper log shows exactly how much wood to remove.

Practice on Scraps

Scribing is a skill that improves with repetition. Practice on short log offcuts before committing to your wall logs. Getting a tight fit on a 15 cm test piece is much cheaper than ruining a 4 m wall log.

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1. Saddle Notch (Easiest)

The saddle notch is a concave scoop cut into the bottom of the upper log, cupping over the lower log like a saddle on a horse. It is the most forgiving notch and the best starting point for beginners.

Step-by-Step

1. Position the upper log on the corner, perpendicular to the lower log.
2. Scribe the profile of the lower log onto the bottom of the upper log at the crossing point.
3. Roll the upper log off to the side, scribed face up.
4. Using a hatchet, make a series of vertical relief cuts within the scribed area, stopping at the scribe line.
5. Knock out the waste wood between cuts with the hatchet.
6. Clean the concave surface with a chisel until it matches the scribed curve smoothly.
7. Roll the log back into position and test the fit. High spots will show as shiny marks — chisel those down.
8. When the notch seats firmly with no rocking, the fit is complete.

Aspect	Rating
Difficulty	Easy
Water resistance	Good — cup faces down, sheds water outward
Structural strength	Moderate — relies on gravity and weight
Self-tightening	No — notch can loosen as wood shrinks
Best for	First builds, round logs, temporary or semi-permanent structures

Always Cut the Notch on the Bottom

If you cut the saddle on top of the lower log (cup facing up), it becomes a rain collector and will rot within a few years. The cup must always face downward on the upper log.

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2. Round Notch (Scandinavian)

The round notch is a refined version of the saddle notch. The scribed groove extends along the full length of the log’s underside (not just at the corners), so each log sits tightly against the one below along its entire span. This eliminates the need for chinking.

Step-by-Step

1. Position and scribe as with the saddle notch, but extend the scribe line along the entire length of the log bottom — not just the notch point.
2. At each corner, cut a saddle-style notch cup.
3. Along the full length, use an axe or adze to carve a shallow longitudinal groove following the scribe line. This groove nests over the crown of the log below.
4. Test fit. The log should contact the lower log along its full length and seat into the notch cups at both ends.

Aspect	Rating
Difficulty	Moderate — full-length scribing takes patience
Water resistance	Very good — no gaps to chink
Structural strength	Good — full-length contact adds rigidity
Self-tightening	Slightly — weight presses groove onto lower log
Best for	Permanent homes in wet climates, experienced builders

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3. Dovetail Notch (Most Advanced)

The dovetail is a flat-sided notch that flares outward, locking the logs together mechanically. Once seated, a dovetail cannot pull apart — it actually tightens as the wood shrinks. This is the strongest and most weather-resistant notch, but it requires the most skill.

Step-by-Step

1. Flatten the top and bottom of each log end at the corner to create flat bearing surfaces. Use a broad axe or saw to create a flat face roughly 2/3 the log diameter wide.
2. Mark the dovetail angle on the flattened face. The classic angle is about 15° from vertical on each side, creating a trapezoidal shape — wider at the top than the bottom.
3. Cut the socket in the lower log: a trapezoidal notch that matches the dovetail shape, angled so the wider part is at the top.
4. Cut the tail on the upper log end: a matching trapezoidal tenon that is wider at the top and narrower at the bottom.
5. Slide the tail down into the socket from above. The flared shape means it locks tighter as weight presses down.
6. Check the fit — the tail should seat firmly with full contact on both angled faces.

Aspect	Rating
Difficulty	Hard — requires precise angled cuts on flat surfaces
Water resistance	Excellent — flat faces with no upward-facing cups
Structural strength	Excellent — mechanical interlock resists all forces
Self-tightening	Yes — shrinkage and gravity pull the joint tighter
Best for	Permanent structures, squared or hewn logs, experienced builders

Start with a Half-Dovetail

A half-dovetail has the angled cut on only one side (the other side is vertical). It is significantly easier to cut and still provides good locking strength. Graduate to full dovetails once you have the technique dialled in.

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4. Square (Flat) Notch

The square notch is a simple flat-bottomed rectangular cutout. It is fast to cut but provides the least weather protection and structural locking.

Step-by-Step

1. Mark a rectangular area on the top of the lower log at the corner crossing, half the log’s depth.
2. Cut matching rectangular notch on the bottom of the upper log, also half the log’s depth.
3. The two half-depth cuts interlock so the logs sit at the same height.
4. This creates a flat-on-flat joint that relies entirely on weight to stay in place.

Aspect	Rating
Difficulty	Very easy
Water resistance	Poor — flat surfaces trap water
Structural strength	Low — no mechanical interlock
Self-tightening	No
Best for	Quick temporary structures, squared timber, situations where you will pin or peg the joint

Pin Your Square Notches

Without a mechanical interlock, square notches can shift laterally. Drive a hardwood peg vertically through each joint to lock it in place.

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Comparison Summary

Notch Type	Skill Level	Cut Time (per corner)	Water Seal	Strength	Self-Tightening
Saddle	Beginner	15–30 min	Good	Moderate	No
Round	Intermediate	30–60 min	Very Good	Good	Slight
Dovetail	Advanced	45–90 min	Excellent	Excellent	Yes
Square	Beginner	10–20 min	Poor	Low	No

Which Notch Should You Use?

• First time building, need shelter fast: Saddle notch. Forgiving, fast, good enough.
• Building a permanent home in a rainy climate: Round notch with full-length scribing. No chinking needed.
• Building with hewn (squared) logs for maximum durability: Dovetail. Worth the time investment for a structure meant to last 50+ years.
• Emergency shelter or outbuilding: Square notch with pegs. Speed over perfection.

Common Mistakes

1. Scribing with the tool tilted — produces a notch that does not seat properly. Keep the scribe perfectly vertical.
2. Removing too much wood — you cannot put it back. Cut conservatively and test fit often.
3. Cutting the saddle on top — creates a water trap. Always cut the concave surface on the bottom of the upper log.
4. Inconsistent notch depth — makes walls uneven. Use the scribe setting consistently across all corners.
5. Forcing a poor fit — if a log rocks in the notch, remove it and chisel the high spots. Forcing it creates stress cracks.

Key Takeaways

• Every notch starts with accurate scribing — learn this skill first.
• Saddle notches are the best starting point: fast, forgiving, and naturally water-shedding.
• Dovetail notches are the gold standard for permanent structures — they mechanically lock and self-tighten.
• Always cut concave notches on the bottom of the upper log so they face downward.
• Cut conservatively, test often, and never force a fit.