An early lesson in carpentry or woodworking in general is to take all of your measurements from a single reference face — this way you don’t get a bunch of accumulated errors that will throw everything off. It makes sense, but what do you do when measuring long distances? or uneven surfaces?
Let’s take a look at this 30 foot long foundation wall I am working on:
In order to lay out the mortises in the sills for the posts I needed to make sure they are in the correct location which was a bit of a challenge.
First off I had to go out and get a 35′ long tape measure. I bought a Milwaukee 35′ Magnetic Tape Measure from Home Depot.
Beyond the length this model has a few nice features I really liked. First and foremost it has a finger protecting stop which is great for people like me that tend to use a thumb as the brake and occasionally get pinched by the end of the tape slamming back into the case. It also has an 8-9′ standoff (distance tape can hold itself out before it bends), a magnet in the end, large hooks and an architect scale (total inches rather than feet) on the bottom of the tape and a supposedly limited lifetime warranty.
I liked it so much I hope to get the 25′ model soon and will retire my Stanley and Stanley Bostitch tapes. You can find the 35′ model here. It’s a bit of a beast, so for everyday use I think the 25′ model will fit better in my tool belt.
In measuring the foundation I found out that its about 1/2″ shy of 30 feet. Other than that I’ve been very happy with how the foundation came out and across its width its consistently 24′ wide as expected.
Laying out the first two sets of mortises from the front of the building was easy and straight forward. The 3rd set is where it got tough as I’d have to bridge the vertical step in the foundation. In order to make that jump I cut a piece of scrap 2×8 and using a level and a square set it exactly on top of the center line for the 2nd set of mortises and clamped it firmly to the cast in place straps.
I could then pull the tape and lay out where that third set of mortises should be and also measure to the end of the building to confirm it matched what I got when just measuring the side of the foundation in a single pull. All the measurements lined up with what I expected, so that was good.
It looks like when the straps were cast in place the concrete contractor measured from the back wall of the building rather than a single reference face and I could see the 1/2″ off they were due to the overall length of the building being off. Thankfully the posts are sufficiently large (6×6) that this won’t be a visible issue.
This all goes to show the value of taking your time and measuring as described above, for if I didn’t do this and laid out the top plates as if the building was an even 30′ long and if I laid out that 3rd set of posts 10′ off the back wall there would be some major problems during the barn raising.
Take care and Happy Measuring,