How To Use a Level Over Long Distances

A 2-ft. level works just fine on small projects like installing small sections of wall tile, building closet walls and installing single cabinets. But when you have to quickly and accurately set elevations over long distances for bigger jobs like building decks, digging trenches and setting concrete form boards, this trusty ol level is out of its league.

Any time you try to pencil a long level line by repositioning that 2-ft., or even 4-ft., level end to end, youll build in an error that magnifies as you extend the line. You can use several tools indoors and out to improve your leveling results. Here, I’ll show you the best techniques and tools for short, medium and long distance leveling.

Combine a Level with a Straight Board

Combining a straight board and a 2-ft. level is a good yet inexpensive way to level shorter distances from 4 to 15 feet. For tasks like laying out deck beam heights (pictured above), set your 2-ft. level on top of a perfectly straight 24 to extend its reach accurately. Two-by-six and 28 lumber is too heavy to hold steady. To make a lot of measurements quickly, strap the level to the 24 with duct tape or an elastic cord.

But it has to be a straight board. I can’t emphasize that enough. Yes, it’s still cheaper than buying a new level, but chances are you won’t be able to get any random 2×4 out of the cheapest pile at the home center. To find the straightest one, sight down the edges. You can always trim a board on a table saw for a straight edge.

If you’re using this method for mounting deck beams, pencil the height of the wall ledger onto each deck post.

Use a Line Level

For jobs where absolute accuracy is less essential, like digging slopes in trenches, use an inexpensive line level. Hook it directly onto a strong string, like nylon masons line. For the level to work properly, use only one line level per string, draw the line very tight, and ensure theres little wind to blow the level around.

Set drainage slopes by measuring from a level string line. Tap in a reference stake and then a series of measuring stakes 6 feet apart along the trench. Check the trench depth for the proper drainage slope by tying off the string line level at each perimeter measuring stake and measuring the depth of that spot in the trench.

Measure off the string line once the level reads true and stabilizes. The line level is true when the bubble settles between the hairlines.

Electronic Water Levels

The simple principle behind a water level is that the water columns inside two open ends of a single tube will be level with each other. Using crude water levels (like a section of garden hose) requires two people. For solo work, we recommend you buy an electronic water level. Its highly accurate, has a 25-foot working radius and allows you to work alone and around corners because it honks when the water in the working tube is level with the reference line back at the unit.

First, calibrate the electronic water level by attaching it plumb and level to a plywood scrap. Fill the tube with water and bleed air out of the line. Calibrate by loosening both tube clamps, turning on the electronic level and raising the working tube to the reference line. The units horn should sound as the water in the working tube touches the reference line. Add red, water-based food coloring for easier viewing when filling the tube with water. Clamp off both tube ends with the clips provided so that water doesnt suddenly spill out.

If you first establish a reference mark at the level and pencil many layout lines around a room (including around corners), you can connect the marks with chalk lines. Measure up (or down) from any line to accurately set acoustical ceiling track, install level wainscoting or add lumber wall blocking for hanging cabinets.

For best results, avoid water leaks from the water level by clipping the end of the working tube when not actually using it for a measurement. Take care not to step on the tube as you move around a room.

If water leaks or air bubbles enter the tubing, you must refill the tube and recalibrate the unit to maintain accuracy.

Laser Levels for Heights and Very Long Distances

Use a rotary laser level for tasks like setting concrete form boards, cutting fence post tops or building retaining walls. The rotary laser shoots a level beam in a continuous circle like a lighthouse. Rotary laser levels are the fastest tools for accurately establishing leveling marks (in direct view of the laser) anywhere on a building site. For big-time savings, rent a self-leveling rotary laser.

Rotary lasers work in tandem with a target laser detector. The lasers continuous beam is too faint to be seen in daylight, so a sensor in the laser detector will chirp when it detects the beam. Mounted on an elevation rod (the kind surveyors use), the laser detector slides up and down the rod until it finds the laser beam to establish the proper elevation.

For the fastest results in setting footing form boards, have one person use the elevation rod to find the laser beam and a second person set the form boards. Prepare a form board for placement by lifting it against a support stake and driving a couple of 3-in. deck screws through the board, ready to set into the stake. Once the laser detector chirps to signal level, drive the screws home.