One of the most effective ways to set a square foundation for your building is the use of batter boards.
Batter boards are the temporary frames used to mark the foundation of a building. They’re set outside the edges of the foundation of the building and suspend the strings used to mark where the exact walls of the building will be.
After clearing and leveling up the site for your building, you now need to square the building. Some of the sites may be gentle and squaring your building might be very easy. For others, you might not be so lucky as they’re steep and to square the building is quite hard. Having a square building is not only necessary but critical for the construction process itself as well as any additions and material fittings later on.
That’s why batter boards can be very helpful in establishing the square for any rectangular building.
In this guide, we’ll take you on a step by step on how to square a building using batter boards. Let’s read on!
To build and set up your batter boards and square your building, you’ll need to know the procedure well. You’ll also need the right materials and tools. So to start with, the following materials are needed.
- Stakes-at least 3 will be needed for each corner
- Boards-2 for each corner
- Carpenters twine
- Dry wood screws
- Building plans
As for the tools you shall require for this procedure, the following are necessary:
- Tape measure – at least 100 ft. measuring tape
- Hammer
- Level (water level, transit, or builders level can be used)
With the above tools and materials in place, what follows is the process to assemble the batter boards and square your building.
Batter Board Setting
Setting up the batter boards is a simple procedure. You’ll need to put a little work and a certain degree of accuracy though. For a site that is almost level, the process should take only a few minutes. However, for steep sites, the process might be hectic and calls for some expertise as well as manpower. To build up your batter boards, follow the following steps for a do it yourself guide:
1. Laying out the rough deck
The batter boards must be set outside the actual layout for the building. They should be at least 3 feet or so from the main foundation of the building.
Start by setting up the rough draft for the building foundation. Mark the lengths and widths for the building and drive in the four stakes, representing the four corners of your building. Using the string, tie the length from the first stake to the other.
Do the same for the width and then repeat for the other two sides until you have marked the four sides of the building foundation. After doing this, you’ve now the rectangular foundation building plan in place. However, this is not square, and that’s why the batter boards come into place. Proceed now to the second step
2. Building the batter boards
To build the batter boards, you’ll need three stakes and two boards for each of the four corners. Choose one corner to be your home base or the starting point. This will be the base for making your measurements and adjustments while establishing the square for your foundation. The reason why it is recommended you do your measurements from a central corner point and not randomly from each corner is for uniformity. Doing it from one reference point avoids errors and ensures accuracy.
Take three stakes and at the chosen reference corner, drive them slightly away from the foundation corner stake to form a right triangle. Then, pin the batter boards horizontally each at the side of the triangle supported by the three stakes. You now have a right triangle. Next, move to the opposite corner and set the batter board as well. This will help in setting the batter at the directly opposite corner quickly as you’ve established the reference corner. Move to the second and the fourth corners and set the batter boards in place. You should be able to form a rectangular layout with right corners just immediately outside the intended walls of the building. The angles need to be precisely 90o or almost.
3. Placing the batter boards into the right locations
The batter boards need to be of the same height all around. This makes it easy to attach the strings for the foundation level and so the layout. When you set the batter boards at the same height, you will have it smooth squaring the corners of the building. Here, you can use either the builders or the transit levels to ensure the batter boards are of the same height.
It is right not to drive the stakes deep into the ground when building the batter boards. This is recommended because when setting them to be of the same height, they can now be driven further into the ground, which is easier than having to pull them from the ground.
4. Attaching string lines to the top edges of the batter boards
Once the batter boards are in place, you’ll need to attach the strings required to square the foundation. Starting from the reference batter board, drive screws into the batter boards where the strings will be attached. Then, attach the strings based on the measurements of the layout for the building.
The strings should match exactly where the outside wall of the building should be. You can use weights to support the strings in position as you move to attach strings to the other batter boards.
After setting the reference batter board strings, move to the batter board opposite it and tie the strings as well. Remember the reference batter board will not be moved or adjusted as it is the home base. From the reference batter board, tie a string diagonally to the opposite batter board stake and mark the point at the end. Measure the distance of the diagonal string.
Go back to the reference batter board and attach strings, this time to the stake perpendicular to it. Attach the two strings to match the outside layout of your building. You now have a right triangle. Therefore, using the 3-4-5 rule, make the angle at the center, the reference batter board, a right angle of 90o.
Since your building is rectangular, you need to go back to the reference wall and attach strings for the other side. Attach strings from the reference batter board to other stakes perpendicular to it and then to the fourth stake opposite it. Use the triangular rule to make the four corner angles, right angles.
Remember, each time the strings are held temporarily by weights. This is because you’ll need to keep moving them as you square the layout. Then after the measurements agree with the square corners for the layout, drive in screws to the batter board to hold them, so they don’t move.
Lastly, measure the distance of the diagonal strings. The two should be equal, an indicator your building layout is now square at the corners. Also, the two opposite sides of the rectangle should be equal. Confirm also the four angles of the building are at 90o. Drive-in screws to hold the strings in a tight position.
5. Adjusting the batter boards to form a perfect square
You now have a rectangular building foundation that is square at the corners. However, the batter boards could have moved during the settings. Their height, for instance, could have changed. You need to do the final adjustments to make them level and maintain a perfect square for your building.
Using the levels, check the height and level of each batter board. Note where an adjustment is needed and adjust them to be of the same level. Make the right adjustments at the same time being careful not to alter the square corners.
When building and setting the batter boards, always remember to make the measurements from a single point which is your reference wall. This will make it possible for you to avoid common errors. The side strings should be attached to the front board on the outside of the building layout. Your measurements should be on the outside of the foundation of the building. Be careful not to mix them up.
Finally, make sure the strings from the front left batter board is attached to the rear right batter board for the two diagonals. The strings from the front batter boards should also go top of the edge of the foundation and tied to the back end on the outside. Check again the rear and the alignment of the front strings is correct.
Using your tape measure, check all the measurements for the two opposite sides. These should be equal. The length of the strings and the corresponding widths should be equal as well. By doing this, you should be able to square the building foundation using the batter boards much easier.
After setting up the batter boards, recheck the diagonals distance and make sure they’re equal. You never know when an alteration can occur and render all your hard work useless. Equal diagonals assure you it is a rectangle. Also, before you call it a day, check the square at all the corners and make sure it is a right angle.