Acceptable Straight Edge?

[NJDan]

I have an 8' aluminum straight edge for checking smaller issues on my concrete garage floor. I was looking at 16' Douglas Fir 2x3's and they look pretty straight. Has anybody here had experience with using those? I just want to assure the floor is as level as possible before I get into tiling.

 

[PCustoms]

A 16' 2x3 is going to be a noddle under it's own weight, nevermind any warp or twist.

Are you checking for level or flatness?

 

[NJDan]

A 16' 2x3 is going to be a noddle under it's own weight, nevermind any warp or twist.

Are you checking for level or flatness?

I want to use it to check flatness. You think it would sag even if used on edge? Maybe use a 2x4 instead?

 

[Big Bad Dad]

Spray the floor with water and watch where it dries first, and where it puddles.

 

[mike93lx]

I'm curious about this mythical straight 16' 2x3...

Use a string line. Grab two cmu blocks (or similarly heavy, known thickness items) and run a string across the space across their tops. Measure down from the string to the floor. It's not as fast as a straight edge, but can be used across the whole garage.

That said, an 8' straight edge is plenty for anything but huge tiles.

 

[PCustoms]

Use a string line. Grab two cmu blocks (or similarly heavy, known thickness items) and run a string across the space across their tops. Measure down from the string to the floor. It's not as fast as a straight edge, but can be used across the whole garage.

That said, an 8' straight edge is plenty for anything but huge tiles.

You can use a laser too, a single setup and a story stick and you can spot check any part of the floor, even as you tile.

 

[NJDan]

You can use a laser too, a single setup and a story stick and you can spot check any part of the floor, even as you tile.

The floor slopes toward the doors but I could use a laser horizontally I suppose. I do have a nice 3D laser. I just wanted to be sure I had no surprises and it would be very easy to get a 16' board from HD and drag it around to see what I see. Maybe I'll see what I see with the laser first. I do know there are a couple of very slight ruts where cars were driven in. I'll be opening a new thread with some questions when I get ready to tile.

Thanks for the replies!

 

[mike93lx]

The floor slopes toward the doors but I could use a laser horizontally I suppose. I do have a nice 3D laser. I just wanted to be sure I had no surprises and it would be very easy to get a 16' board from HD and drag it around to see what I see. Maybe I'll see what I see with the laser first. I do know there are a couple of very slight ruts where cars were driven in. I'll be opening a new thread with some questions when I get ready to tile.

Thanks for the replies!

Ruts from cars on a concrete floor? Never seen that before.

 

[NJDan]

Ruts from cars on a concrete floor? Never seen that before.

I knew "ruts" was probably the wrong word. Maybe slight depressions from wear is more accurate. I'm talking a very small amount and I haven't done a comprehensive look at the floor (hence the 16' board question) but for now that's what it looks like. You probably wouldn't notice it by walking on it.

 

[brianpgriset]

Put a flashlight on the ground a turn off all the lights. You’ll see high and low very easily.