1

I want to build a new building next to an existing building. The new building must be parallel to the old building, but shifted forward, as shown below. What is the best way to find a parallel line to the existing building in order to mark and set the footers for the new building?

For example, an existing building is here:

+----------------------------+
|                            |
|                            |
|                            |
|                            |
+----------------------------+

I want to add another building a few feet away, shifted halfway to the right but maintaining parallel walls with existing building:

               +------------------------------+
               |                              |
               |                              |
               |                              |
               +------------------------------+

What's the best way to find the parallel line?

  • How far apart? Is the ground between them flat? Level? – manassehkatz-Moving 2 Codidact Jun 5 '19 at 18:10
  • Let's say 50 feet apart, yes the ground is flat with no obstructions between them. – Ryan Griggs Jun 5 '19 at 18:13
4
+----------------------------+
|                            |
|                            |
|                            |
|                            |
+----------------------------+

[*]-------------------------[-]---------------------[*] <-- stake with nail   
 ^-- stake with nail at      ^-- stake at roughly           set under extended
     arbitrary distance          the same distance,         carpenter's line
     from bldg                   with mark at exact
                                 distance

               +------------------------------+
               |                              |
               |                              |
               |                              |
               +------------------------------+

Set a reference line as shown, then just take measurements from that as needed.

| improve this answer | |
  • I see how this could work, but what if we failed to measure from the existing building at an exact 90-degree angle? This would skew the stake placement, causing the new line to be out of parallel. Am I missing something? – Ryan Griggs Jun 5 '19 at 18:53
  • Within a few inches of square the error is negligible. Carpenters would get nothing done if they had to square every measurement they made. :) Make it a point to eyeball for square and be happy. If you're really worried, lay a framing square or something against the building as a guide. – isherwood Jun 5 '19 at 19:08
  • 1
    You can test this after your line is set. Swing side-to-side and find the point with the shortest dimension. That's square, or close to it. You'll find that there's a range where the measurement doesn't appreciably change. Check both corners of the building for consistency. – isherwood Jun 5 '19 at 19:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.