Local machinists: I need a 10' straightedge.

[steelheart]

I need a 10' straightedge that I can use to determine that a concrete floor is within spec for laying porcelain tile, that is, it is flat to within 1/8 inch over 10' when measuring from the high spots:

“the maximum allowable variation is no more than 1/8” in 10’ (3 mm in 3 m) and no more than 1/16” in 2’ (1.6 mm in 0.6 m) from the required plane, when measured from the high points in the surface.”

I'm based in Reston, Virginia, USA. Of course, I'll be willing to pay for your services. This is something I'll need to have within 2 weeks.

Thanks!

Stephen

 

[RJSakowski]

I use a length of 3" Aluminum channel for a straight edge for jobs like yours. It's available from heavy hardware suppliers. The AA profile has straight walled flanges. I just finished laying a patio using a 12' length.

 

[Barncat]

Can you just pull a string tight across it and measure? Or a laser.

 

[Timwalker]

With that loose of a tolerance, I think it would be worth looking into whether an aluminum extrusion would fit your needs. Would probably be worlds cheaper than having a 10 foot straight edge machined.

 

[Latinrascalrg1]

Is this some kinda super special environment for some reason or is this just a basic home improvement project?

 

[Cadillac]

You can buy a 8’ level from just about any big box store that should be plenty good for a tile job.
I’ve laid hundreds of square feet of tile and really never worried about if the subfloor was level or not to a 1/8”. If the floor isn’t sound and wavey then that’s another story. Tiles 12x12 and under can take deviation like that. Larger ones not so much. Butter the back of the tiles and do you typical notch trowel should be good. Thinking of it I wonder how many floors are that level?

 

[Cadillac STS]

I was at Lowe’s today and they sell a 6 foot ruler/straight edge. Could buy two of those and clamp them together. And with the inch marks you can measure your variance more easily.

 

[whitmore]

I need a 10' straightedge that I can use to determine that a concrete floor is within spec for laying porcelain tile

That's an easy job for a laser; a ten foot stick would be hard to haul, store, or handle, but a little laser-and-mirrors item
can come out of the box, sit on the floor, and broadcast a flat sheet of light; drop a yardstick to the floor at any point,
and read off the deviation from that.

"Rotary laser levels" often have a float, or plumb bob, built in (these are self-leveling), so they will ONLY measure level-and-flat, not flat-and-sloped,
If slope is OK, it'll take some close reading of the instructions (or maybe a very dumb model). Mathematically, you could
identify the slope direction and use a grid aligned to it for a quick check of flat, but that's a tad tedious.

The old-fashioned way, is a handheld sight level, maybe with a monopod, and an assistant holding a stadia stick; I remember using those, but
haven't played with the rotary laser gizmos. It might be worthwhile renting one before shelling out the cash (they're
expensive, but so are good levels).

 

[lordbeezer]

This is a great site..don't care what questions someone asks there's a bunch of really smart people that take time to answer..not common in today's world

 

[JimDawson]

I'm surprised that nobody has mentioned leveling compound. Just poor it on and presto, instant flat floor for tile. At least that's the way I understand it.