That moment you realize your reference layer is 20 years old

I was drafting a remodel for a house built in 2003 and pulled the old prints from the city. Turns out the original drafter used a different datum for the elevations. I cross checked with a laser measure and found a 4 inch difference between the plans and the actual foundation height. How do you guys catch stuff like this before it becomes a problem on site?

2 comments

2 Comments

terrybennett13d ago

Man, learned that one the hard way too - always double check benchmarks with your own gear before cutting anything.

carr.brooke13d ago

There's always something hiding in the old plans that nobody thinks to check. I've seen guys trust a twenty year old benchmark without ever pulling out a level on site. What catches most people off guard is that the original crew might have worked off a temporary benchmark that got lost or moved over time. A four inch difference is huge if you're tying into existing windows or doors. Best habit I ever learned was to shoot your own elevations the day you start, no matter how old the prints are.