How to Set Up Batter Boards for a Log Cabin Base
Once you have chosen the spot for your log cabin, it needs a solid base. You can use paving slabs, a concrete slab or – as we did – concrete strip foundations. Whatever you choose, the base must be perfectly level, and you need to be able to find the exact height and the exact corners at any time. Working with a spirit level and a straightedge is slow and inaccurate over several metres, so we set up batter boards first.
Quick answer:
- Drive three pegs at each corner, about 1 m (3 ft) outside the planned building.
- Mark a height on one peg and transfer it to all pegs with a water level.
- Screw horizontal boards to the pegs with their top edge on the marks – now all boards are level with each other.
- Stretch strings along the outer walls and move them until both diagonals are equal – then the layout is square.
- Notch the string positions into the boards so you can take the strings off and put them back exactly.
What you need
| Item | Quantity | Note |
|---|---|---|
| Wooden pegs, 8 × 8 × 100 cm (approx. 3 × 3 in × 3 ft 3 in) | 12 | Slightly thicker is fine; round posts work too |
| Boards, at least 50 cm (20 in) long | 8 | Two per corner |
| Screws | a handful | To fix the boards to the pegs |
| Mason's line (string) and weights | 4 lines | We used stones to keep the strings taut |
| Water level and spirit level | 1 each | A helper makes the water level much easier |
The pegs must be strong enough to take the pull of the strings and weights without moving – a peg that leans by a few millimetres shifts your whole layout.
Setting up batter boards step by step
- Mark out the cabin. Mark the rough position of the cabin on the ground, for example with sand. This is also the moment to check once more the orientation and the distances to the boundary and to other buildings.
- Drive the corner pegs. About 1 m (3 ft) outside each corner, drive in the first four pegs (numbers 1–4 in the diagram). The distance matters: the batter boards stay in place while you build the base and must not get in your way. Depending on the soil, drive the pegs about 50 cm (20 in) into the ground – sharpening them helps.
- Drive the remaining pegs. Drive pegs 5 to 12 roughly parallel to the sides of the cabin, so that each corner gets an L-shape of three pegs.
- Mark the height. On the first peg, make a mark about 50 cm (20 in) above the planned top of the base or foundation.
- Transfer the height. Transfer this mark to all other pegs with a water level (guide in German). Wait until the water has settled before you mark, and make sure there are no air bubbles in the hose.
- Fix the boards. Screw the boards to the pegs with their top edge exactly on the marks. Now all boards are level and at exactly the same height.
Lining up and squaring the corners
The batter boards do not just give you the height anywhere on the site. We also used them to set out the line and the right angles of the cabin – and of the base frame.
- Stretch the first string. Stretch a mason's line along one side of the cabin, across two opposite boards. We tied stones to the ends to keep it taut.
- Add the other walls. Mark the positions of the other outer walls with strings in the same way.
- Check the diagonals. Measure the diagonals between the points where the strings cross. In a perfect rectangle both diagonals are exactly the same length. You can also calculate the correct diagonal with Pythagoras: a² + b² = c².
- Adjust. Slide the strings along the boards until the diagonals match.
- Notch the boards. Mark the string positions on the boards, remove the strings and cut small notches at the marks. The strings can no longer slip and can be put back in exactly the same place at any time.
Example: For a cabin of 3 × 4 m, the diagonal must be exactly 5 m (√(3² + 4²) = 5). This is also the idea behind the classic 3-4-5 method for a single corner: measure 3 units along one string and 4 along the other – if the distance between the two points is exactly 5, the corner is square.
| Cabin size | Diagonal |
|---|---|
| 2.5 × 3 m | 3.905 m |
| 3 × 3 m | 4.243 m |
| 3 × 4 m | 5.000 m |
| 4 × 5 m | 6.403 m |
| 10 × 12 ft | 15 ft 7½ in (15.62 ft) |
With the batter boards in place, we could find both the heights and the exact position of the outer walls – and therefore of the base frame – at any time. That gave us the exact position of the foundations, and we could start on the concrete strip foundations.
Frequently asked questions
How far from the corners should batter boards be?
About 1 m (3 ft) outside the planned corners. The batter boards stay in place while you dig and build the base, so they must not be in your way – and they must not be disturbed by the digging.
How high should batter boards be?
Set the top edge of all boards to the same height, a fixed distance above the planned top of the foundation. We used 50 cm (about 20 in). From the string you can then measure down to the exact foundation height anywhere on the site.
How do you square batter boards?
Measure both diagonals between the points where the strings cross. In a true rectangle both diagonals are exactly the same length. Move the strings along the boards until they match, then mark and notch their position on the boards. For a single corner you can also use the 3-4-5 method.
How do you get all batter boards level with each other?
Mark the height on the first peg and transfer it to all other pegs with a water level – a clear hose filled with water. It is accurate to about a millimetre over long distances and around corners. Then screw the boards on with their top edge exactly on the marks.
Next step: Log cabin base: strip foundations and timber frame · Back to the log cabin overview · German original: Schnurgerüst bauen