I see other people asking similar questions, but it seems most have some wood to cut off the top of the post - I didn't plan for that when I cut it, so I want to get it level on the tops, and bottom however fits.

Note: this is not just a fence, it's being made to hold my solar panels on the top - relatively short posts, but I want them flat on the top. The posts are either 4x4 or 4x6, and across the top is a 4x4x8' - posts 4 feet apart, with the 4x6 posts at the points of two 4x4x8' top beams meeting.

I did attach the top beam originally, but it was sortof twisting by the end, so I couldn't put the posts in level with the top beam in. I took off the top beam and now have just posts in holes I want to make sure the tops are level of.

I'm thinking, I will set 1 post at a time, and get a board across to the next one with a level to make sure it's level between the set post and non-set, before pouring the next, and so on for all of them? Anyone know or suggest a better method? I have 0 past experience setting a fence btw - so feel free to point out the obvious for you that I may be missing. Thanks!

  • can you not get a horizontal board that is straight ?
    – Traveler
    Commented Aug 13, 2022 at 4:19
  • 2
    Unfortunately you precut the posts, so the only adjustment you have is how deep is the hole
    – Traveler
    Commented Aug 13, 2022 at 4:24
  • Tight level string or laser level or water level (no bubbles in the tube, though or they are not level) or (straight) board and level. Fundamental problem being getting the posts to actually set where they are level. That is not simple to do at all.
    – Ecnerwal
    Commented Aug 13, 2022 at 12:36

2 Answers 2


I have a laser level - take the shortest post and use that as the master.

I would have planned to set all the posts to roughly desired height and then trim to final height as the last step.

  • 1
    Last time I levelled posts, had to use a string level. Times have changed.
    – crip659
    Commented Aug 13, 2022 at 10:13
  • 1
    @crip659 it is a 24" level, with bubbles at 0, 1, 2, 3 and 4 degrees as well as the laser. works well for slopes like gutters etc Drop a hint for your next birthday or xmas present :)...
    – Solar Mike
    Commented Aug 13, 2022 at 10:15

Your board idea will work, but it's not the easiest.

With all the posts loosely set in the holes, find the tallest. This is where you'll start. Set it plumb and square and where you want it in the hole relative to all your other holes. If you have the time, do the concrete for this one and let it set. (It helps to not have your reference post moving around.)

Now, from your reference post, do the far corner. Make the hypotenuse of the triangle as perfect as possible. With a water level (clear tubing longer than the hypotenuse, water inside, maybe a drop of food coloring to help see the level, and preferably an assistant), bring the far post up to the height of your tallest and start the concrete. With the post held up to the right height, screw some outriggers onto the post to hold it plumb and square at that height. If you don't have tubing for a water level, you can use string and a regular spirit level. The issue there is that you want your string taut, so it tends to affect the post you're working on.

Rinse and repeat for the rest of your posts. It wouldn't hurt to attach your beams etc while the concrete is still wet, as this will ensure the posts are square to each other and in-line if you have more than 4.

String will help you get the posts twisted square to one another while you're putting everything in place. Put a standard size hunk of something under each end of the string (for instance, a small square of 1/2" plywood) so that the string is offset from the middle post(s) by that amount. If you haven't already attached your beams, you could also clamp them to the sides of the posts to ensure squareness while the concrete sets.

Truthfully, it's easier to just set the posts and cut the tops to the lowest height after everything has set.

  • 2
    The string, if used, should not even touch the items being referenced to it. It should be supported on a batter board (beyond the item you are checking) and run near, but not touch the post - so its tension does not affect the post (and the post isn't pushing it out of line.)
    – Ecnerwal
    Commented Aug 13, 2022 at 13:37
  • Batter boards / strings are an excellent idea for getting a perfect layout. Especially if the reference post isn’t locked in the day before. Commented Aug 13, 2022 at 14:12

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