Compact Line, Dot and Combo Laser Levels for Construction Applications

In this blog I'll talk about line, point and combo laser levels. This class of tools goes by a lot of names: chalk line laser, line generator, self-leveling laser, line laser, laser spirit level, point or dot laser, etc. 

Before we take a "deep dive", an important comment: if you are working mainly outdoors then you should really consider a more robust, more accurate rotating laser with a professional quality detector. Many compact laser levels can also work outdoors up to 100' range by using a line-laser detector, but they are primarily designed for interior use. You can put a fine-tooth blade on a Milwaukee Sawzall®, but that doesn't make it the right tool for cutting crown. 

(Check out the Leica Rugby rotating laser below)


Laser Levels 101

I've spoken with contractors that were burned by a poor quality laser level in the past. Many forward thinkers started using laser levels some years ago and struggled with the quality of what was on the market. There is always the risk of companies trying to pass off a DIY product as a professional tool. Below summarized some key information about laser levels to help you ask the right questions when you are doing your research. Get a strong cup of coffee and dig in.

a. Typical Laser Level Configurations:

  • Point lasers emit 2, 3 or 5 perpendicular laser beams and are used to transfer points from floors to ceilings, for laying out 90 degree walls (3,4,5 method), or for transferring heights.
  • Line lasers project horizontal or vertical level lines in a “fan angle” that ranges
    from +/- 60 degrees to  more than 180 degrees. Line lasers are used to mark
    level lines, align objects in a space (window sills in a room, upper kitchen cabinets, chair rail, electrical switch boxes, etc.
  • 180° line lasers are similar in concept to line lasers but have wider fan angles (often >180°). By setting the laser in a corner of a room, the large fan angle allows the laser to project a level horizontal or vertical line around the entire room. These lasers often need larger "windows" to emit the laser light, making the housings slightly larger than typical line lasers.
  • Combo lasers are exactly what you expect, a combination of lines and points. Send the crew out with a combo laser and they’ll have all the tools they need. A combo laser usually is denoted by the number of lines and points the tool projects (L2P5 – 2 Lines and 5 Points).
  • Multi-line lasers started in Asia and are rapidly gaining acceptance in the USA, mainly due to the number of level planes projected. The downside is their cost and larger size.  Like the combo lasers, multiliners are spec’d by the number of horizontal and vertical planes as well as projected points. The planes of a multiliner will intersect forming a "point" on a surface, so most multiline lasers have only 1 true „point“, the laser plumb down on the ground.


b. Manual vs. self-leveling lasers – Most pros are looking for an automatic (self-leveling) laser tool – a tool to mark or verify that an object is level or to transfer heights around a room. The best way to save setup time is to use an automatic laser level. Install the tool on the tripod and switch it on. As long as the tool is rough-leveled within ~4 degrees, the laser will switch on and display a level laser plane. If the level is bumped, it will automatically re-level as long as it remains in the “working range” of the leveling mechanism. If the level is bumped out of its working range the laser switches off or will start to blink to notify you of a problem. Maintaining level is not a concern with self-level laser tools, however, it is important to make sure the laser line is stays on your reference height. If someone bumps the tool and shifts your tripod, or a shim, you could end up working at a different height even though the tool is still level. Its always good practice to check your reference a few times the day.

Sometimes you'll see low priced manual laser levels. Different from a self-leveling laser, a manual laser level requires your crew to level the laser by hand (and must keep checking it during the day to make sure it stays level) using some type of bubble level and adjustment screws on the laser base. Manual leveling lasers are time consuming and can cause big problems if someone accidently bumps the laser out of level. A manual laser level beam will not blink to indicate it is out of level.

(See the Leica Lino L2G+ self-leveling function below)



c. Power to work throughout the day – most self-leveling lasers use alkaline cells or some type of rechargeable battery system. The new green lasers on the market have brighter beams than red lasers, but also use more battery power than a red laser (some green lasers have a run time as short as a couple of hours!). Compared to a water level or a plumbob, you’ll be spending some money on batteries when you switch to a self-leveling laser, but you’ll be spending less time on the job thanks to increased productivity and better product quality. For those who want to be more environmentally friendly, there are rechargeable options (both built-in) and external. If you have built-in batteries – make sure you can “run-charge” them, meaning charge the batteries while you use the tool. A great setup is a rechargeable option using standard battery size (for example, AA). You’ll get multiple recharge cycles from a set of cells, plus in a pinch you can throw in some alkalines.

d. Pendulum lock – To understand this topic you need to know how a self-leveling laser works. Think of a miniature mechanical pendulum supported on ultra-precision ball bearings. The laser is attached to the pendulum. The pendulum always seeks to hang straight down because of gravity (level). Bump the laser and the pendulum will swing and quickly settle down back on level (and so will your laser line). But there are times when you might need a sloped line (example, locating handrail bracket install points on a stairway). A pendulum lock allows you to lock the pendulum to stop it from swinging. Once the pendulum is locked, you can simply tilt the laser and the projected line will tilt as well. An important benefit of the pendulum lock is the protection of the precision gimbal bearings when the laser is accidently dropped. Quick summary – you want a pendulum lock.

e. Housing and tool construction – Will a big rubber bumper around the tool protect it from a drop? Maybe, maybe not.  A poorly designed tool can’t be saved by a ¼” thick piece of rubber no matter how "cool" the bumper looks. The durability of the laser tool is engineered from the inside out. We all know that cheap tools are cheap for a reason. Better to have a solid tool with a pendulum lock and treat it like a precision measuring tool. It doesn’t need to be treated like a work of art, just don’t abuse it. And don’t forget to check the leveling accuracy occasionally - it never hurts.

f. Range and accuracy – A major driver of line leveling accuracy is the pendulum setting (that's why you want to protect the pendulum from hard shocks with a lock). The accuracy is expressed as levelling error over a given range, like 1/16” at 15’. Double the range to 30’ and the error doubles to 1/8”. At 8' you should have half the error – but sometimes the laser line is wider than the accuracy specification. Many laser levels claim 1/16” accuracy at 15’. Problem is, a cheap laser level 15' from the target will project a laser line that's ¼” wide – good luck getting that square peg in that round hole. It is important to have a bright, clear, focused line. You’ll know a good laser when you see it switched on.

g. Green vs. Red laser -  A true green laser diode costs more than a red one, but if you use a laser level for hours at a time you will appreciate the difference. The state-of-the-art direct emitting green diode technology produces a bright, green line with less “beam speckle” than red lasers. The result is a clean, sharp laser line across your work surface. The green wavelength is 3-4x more visible to your eye than a red laser. This means you can normally see the green laser from a farther distance than a red laser. Longer visible distance means fewer setups and fewer setups means less time needed to finish the job.

h. Fan Angle – Imagine a fan angle like standing with your outstretched arms at your sides. From your right arm to your left arm is 180° fan angle. Stand against a wall and everything from your right arm to your left arm is in the laser plane.  Place a laser with 180° fan angle in a corner and you have a level plane in the entire room. One setup for the entire room. Saves time and money.

i. Beam quality – Look closely at the beam against a wall from a distance of 15 feet or so. Look for sharp, bright lines. Lower quality laser tools will have fuzzy and intermittently dim lines, “ghost” or parallel lines, dead spots in the lines. Seeing is believing.

j. IP54 or IP65 - IP stands for “Ingress Protection” – or, in other words, resistance to dust and moisture. For the “do-it-yourselfer” you’ll find IP40 disposable lasers (watch out for dust and moisture!). If you care about your tools and your work, don’t buy anything below IP54 – dust and moisture resistant. An IP54 tool can get dusty or damp. For the hard-core, go for IP65, Mil-Spec or higher. Drop it in the mud, wash it off with a hose. Many IP65 products are also rated for 3-6’ drop resistance as well. Regardless of tool and IP rating, a word of advice: NEVER, NEVER put a wet tool in a closed case.

(Here's a video of an IP55 Leica Total Station torture test - this thing costs $45,000!)



k. After the purchase – I recently talked with a counter guy in Vegas and asked him how he trained people to use a laser level. He cocked his head to one side, looked at me with a puzzled face and said, “Open the box, put the batteries in and turn it on. What’s to train?”

You probably won’t need a 24 hour call center to help you use your laser level. But you might need a warranty. Buy a quality product from a reputable manufacturer that actually has a physical presence in the USA and a simple "exchange" warranty. If the tool doesn’t meet the manufacturers specs during the warranty period, you get a new tool. The warranty on these tools is usually between one and three years. Don’t expect a laser with a crushed housing to be exchanged free of charge. Warranties cover normal wear and tear and manufacturing defects.

Enough for now. In future posts I'll dig into typical applications (comparison of "old-way vs. new-way") and how to check calibration on your automatic level.