Ladder Safety: Types, Sizing, and Safe Use

Ladder falls send over 500,000 people to the emergency room every year in the United States, according to the Consumer Product Safety Commission. The vast majority of those injuries are preventable. The three causes, in order, are using the wrong ladder for the job, setting it up incorrectly, and overreaching while working. All three are straightforward to avoid once you understand the rules.

Ladder Types and When to Use Each

Step ladders are self-supporting A-frame ladders that do not lean against anything. Use them indoors or outdoors for tasks up to about 10 to 12 feet off the ground. On a 10-foot step ladder, you stand on the third rung from the top, which puts your feet at about 8 feet. Never stand on the top cap or the top two rungs of a step ladder. Step ladders are the right choice for painting ceilings, changing light fixtures, shelf work, and anything where you need to work without a wall to lean against. Werner, Louisville, and Little Giant all make residential step ladders in 4-foot through 12-foot heights.

Extension ladders lean against a surface and are sized by their extended length. A 24-foot extension ladder, when extended and set at the proper angle, reaches about 21 feet of usable height. Use them for gutter work, painting exteriors, roof access, and tree trimming. Extension ladders require a solid surface to lean against and firm, level ground at the base. They are not suitable for freestanding use. Werner, Louisville, and Keller are the most common brands at home improvement retailers, with prices ranging from $150 to $500 depending on length and material.

Multi-position ladders convert between A-frame, extension, scaffolding, and stairway configurations. The Little Giant King Kombo and Werner MT series are popular multi-position models. They are versatile for homeowners who do not want three separate ladders taking up garage space. The tradeoff is weight: a multi-position ladder that covers the same height range as a step ladder and a short extension ladder typically weighs 35 to 50 pounds, compared to 20 to 25 pounds for a dedicated step ladder. For more on using ladders during gutter work, see our Gutter Maintenance Guide.

Weight Ratings

Every ladder has a duty rating that specifies the maximum weight it can safely carry. That weight is you plus your tools and materials combined, not just your body weight. The ANSI (American National Standards Institute) duty ratings are: Type III (light duty) at 200 pounds, Type II (medium duty) at 225 pounds, Type I (heavy duty) at 250 pounds, Type IA (extra heavy duty) at 300 pounds, and Type IAA (special duty) at 375 pounds.

Most homeowners should buy at least Type I (250 pounds). If you weigh 200 pounds and carry a 5-gallon bucket of paint (about 60 pounds), you are already at 260 pounds, which exceeds the limit on both Type II and Type III ladders. People routinely underestimate the combined weight of themselves plus tools, hardware, and materials. A tool belt with a drill, fasteners, and a few hand tools adds 15 to 25 pounds easily.

Buy one rating above what you think you need. The price difference between a Type II and a Type I ladder is typically $20 to $40, which is a small cost for a significant safety margin. Type IA and Type IAA ladders are heavier and more expensive but appropriate for anyone over 220 pounds or for tasks that involve carrying heavy materials up the ladder. Manufacturer specs and the duty rating label are on the side rail of every ladder sold in the US.

Extension Ladder Setup

The 4-to-1 rule: set the base one foot away from the wall for every four feet of ladder height to the contact point. A 20-foot extension ladder contacting the wall at 20 feet should have its base 5 feet from the wall. Too steep and the ladder can tip backward when you lean out or shift your weight. Too shallow and the base can slide out on you. Most extension ladders have angle indicator stickers on the side rail, but measuring the base distance is more reliable, especially on uneven terrain.

The ladder must extend at least 3 feet above the landing point (the roof edge, for example) so you have something to hold onto when transitioning on and off. This is an OSHA requirement for workplace ladders and a critical safety practice for home use as well. Without that 3-foot extension, you have nothing to grip when stepping from the ladder onto the roof or back onto the ladder from the roof, which is when most extension ladder falls happen.

Both feet must be on firm, level ground. Soft ground, gravel, or mud can allow the feet to sink unevenly under load. Uneven ground needs a ladder leveler (an adjustable leg extension, available from Werner and others for $20 to $40) rather than improvisation. Never stack boards, bricks, or blocks under one leg to level a ladder. Lock the rung locks on both sides before climbing and give the ladder a firm shake to test stability. If it shifts at all, reposition it before climbing.

Safe Climbing and Working

Three points of contact at all times: two hands and one foot, or two feet and one hand. This rule applies during climbing, descending, and while working on the ladder. Carry tools in a tool belt or hoist them up in a bucket on a rope, not in your hands while climbing. Face the ladder when climbing and descending. Going down a ladder facing outward is a common cause of falls because your weight shifts away from the ladder.

Never step on the top two rungs of a step ladder or the top three rungs of an extension ladder. These positions put your center of gravity above the support points and make the ladder unstable. The top of a step ladder is a platform for the locking mechanism, not a step, regardless of how flat and sturdy it looks. Manufacturer labels on every ladder sold in the US warn against standing on these positions.

Do not overreach. Your belt buckle should stay between the side rails at all times. If you need to reach further, climb down and move the ladder. This is the rule people violate most often, and it is the most common cause of ladder falls. Moving a ladder takes two minutes. A fall from even a 6-foot step ladder can result in broken bones, head injuries, or worse. According to the CPSC, the average ladder fall results in 11 days of missed work. The math strongly favors moving the ladder.

Inspection and Storage

Inspect ladders before each use. Check for bent or cracked rails, loose rungs, damaged feet, and worn rope on extension ladders. Aluminum ladders can develop stress cracks at welds, particularly around rivet points and where the fly section meets the base section. Fiberglass ladders can crack or delaminate from UV exposure, showing surface fibers or a chalky texture. Wood ladders can crack or develop loose joints from moisture cycling. If a ladder fails any inspection point, take it out of service immediately. Do not try to repair structural ladder damage. A compromised rail or rung can fail catastrophically under load.

Store ladders horizontally on wall hooks or brackets to prevent warping. Vertical storage against a wall can cause fiberglass and wood ladders to bow over time. Keep fiberglass ladders out of direct sunlight when not in use. UV radiation degrades the fiberglass resin over time, weakening the structural integrity. If your fiberglass ladder shows a chalky surface or visible fibers, it has significant UV damage and should be replaced. Store aluminum ladders away from chemicals that cause corrosion, particularly fertilizers, pool chemicals, and road salt.

Clean mud and debris from the feet after each use so the traction pads maintain their grip. The rubber or plastic feet on ladder legs are replaceable on most models. If they are worn smooth, cracked, or missing, replace them before using the ladder. Replacement feet cost $5 to $15 per pair and are available from the ladder manufacturer or at hardware stores. Intact, grippy feet are a critical safety component, especially on smooth surfaces like concrete, tile, or hardwood floors.

Frequently Asked Questions

What Size Ladder Do I Need for a Two-Story House?

A 24-foot extension ladder reaches about 21 feet of usable height. You lose about 3 feet for the setup angle (the 4-to-1 rule shortens the vertical reach) and the 3-foot extension above the roof line. That is enough for most two-story houses with eaves at 18 to 20 feet. For gutter cleaning on a single-story house, a 16- to 20-foot extension ladder is sufficient. Measure the height you need to reach before buying, and remember that a longer ladder than necessary is safer than a shorter one that tempts you to stand on the top rungs.

Should I Buy Aluminum or Fiberglass?

Fiberglass is the safer choice for any work near electrical lines or on the exterior of a house where overhead power lines might be present. Fiberglass does not conduct electricity; aluminum does. A metal ladder that contacts a live power line can be fatal. Aluminum is lighter (typically 20 to 30 percent lighter than an equivalent fiberglass ladder) and less expensive, which matters if you move the ladder frequently or carry it long distances. For a homeowner buying one extension ladder, fiberglass is the recommendation because it handles every situation safely. The weight penalty is real but manageable for occasional use.

Can I Use a Ladder on Stairs?

Not a standard step ladder or extension ladder. They require level ground on both sides (step ladder) or at the base (extension ladder). A multi-position ladder with adjustable legs can be configured for stairway use, with one leg extended to compensate for the step height difference. The Little Giant King Kombo and Werner MT-22 both support stairway configurations. Purpose-built stairway ladders also exist from Werner and others. Working on stairs with a non-adjustable ladder is one of the most dangerous common ladder misuses because the footing is inherently unstable and the fall distance increases with each step below you.

Related Reading

• Gutter Maintenance Guide