How to Choose an Extension Ladder

An extension ladder is the tool that gets you up to the roofline, the gable, the second-story soffit, or anywhere a stepladder runs short. Two sections, sometimes more, that slide and lock to reach the height you need. The buying decision comes down to three things: what it’s made of, how much weight it’s rated to carry, and how tall it actually reaches. Get those right and the rest is detail.

The first call is material. Working anywhere near electricity? Fiberglass rails are non-conductive for working near electricity. That’s not a preference — it’s the rule. Painters, utility crews, anyone running a ladder near a service drop or overhead line goes fiberglass, full stop. Fiberglass also sits more rigid underfoot. Aluminum is lighter to haul and won’t corrode, which matters when the truck-to-jobsite carry is long. But for general trade work where electrical exposure is even a remote possibility, fiberglass earns its weight.

The duty rating is the second call, and people get it wrong by underbuying. The rating covers the climber plus tools, materials, and whatever else rides up the ladder — not just bodyweight. A 220-pound framer with a tool belt and a bundle of shingles blows past a 250-pound rating fast. Here’s how the types stack up:

Duty Rating (Type)	Load Capacity	Typical Use
Type IAA	375 lb	Heavy professional / extra-heavy duty
Type IA	300 lb	Professional, general construction
Type II	225 lb	Medium duty
Type III	200 lb	Light duty, lighter aluminum

The 24-foot fiberglass leveling model carries a duty rating of 375 pounds — that’s the Type IAA tier, built for the heaviest loads.

Sizes and Reach — Don’t Confuse the Numbers

This is where buyers trip. The number on the label is the ladder’s nominal length, not how high you can stand or reach. The sections overlap when extended, so a 24-foot ladder doesn’t put your feet at 24 feet. Plan for usable reach, not the sticker number, and buy a little taller than you think you need to avoid stretching off the top rungs.

Western Building Center’s extension ladder lineup, all Werner, spans these sizes and types:

Size	Material	Duty Rating
16’	Fiberglass	Type IA
20’	Fiberglass	Type IA
28’	Fiberglass	Type IA
32’	Fiberglass	Type IA
20’	Fiberglass	Type II
24’	Fiberglass	Type II
16’	Aluminum	Type III (200 lb)

The lineup leans heavily fiberglass — sensible in trade country where electrical work and exposure are constant. The single 16-foot aluminum Type III is the lightweight option for around-the-house jobs where weight matters more than maximum load.

Setup and Safety Basics

A good ladder set up wrong is still dangerous. Place the ladder on a level, stable base at a 65 to 75-degree angle — roughly a 1:4 ratio. That means for every four feet of height, the base sits one foot out from the wall. Make sure it extends at least a meter above the landing point and is secured if necessary.

Inspect before every climb. Check that locking catches are functional and look the ladder over for damage. In Montana winters this matters more than most places — a ladder coated in snow, ice, or mud loses its footing and its grip. Knock it clean and dry before you trust it.

The fiberglass models bring real climbing comfort and durability features. The exclusive Alflo rung joint means Twist-Proof performance, with 1.63-inch slip-resistant Traction-Tred D-rungs. Dual action feet with a slip-resistant pad and spur plate work on hard or penetrable surfaces — pavement or soft ground, the foot adapts.

Handling Uneven Ground

Rural Montana jobsites rarely give you a flat pad. Slopes, gravel, soft shoulders — uneven footing is the norm, and it’s the most common way a ladder ends up dangerously canted. Werner’s leveling system addresses it directly. On the LevelSafe Pro models, factory-installed levelers enable the ladder to adapt to uneven terrain — simply set the ladder down to automatically level. Micro-Adjusting handles allow precision leveling, and each leveler can extend up to 8.5 inches. That’s nearly nine inches of adjustment per side for a slope that would otherwise force you to dig a footing or stack blocks.

If lighter handling is the priority, Werner’s AERO series trims weight without giving up capacity. It carries a 375 lb load capacity at a Type IAA duty rating. It runs about 25% lighter than the comparable D7100 series, using a patented BoxLok interlocking box rail design for strength, rigidity, and weight savings, with reduced deflection, sway, and twist plus wide rungs for a steadier climb.

Frequently Asked Questions

Fiberglass or aluminum — which should I buy? If there’s any chance of working near electricity, buy fiberglass. Fiberglass rails are non-conductive for working near electricity. Aluminum is lighter and won’t corrode, making it easier to carry and store, but it conducts. For most trade work where electrical exposure is possible, fiberglass is the safer default.

What does the duty rating actually cover? The climber plus everything they carry up — tools, materials, fasteners, the works. Not just bodyweight. The tiers run from Type IAA at 375 pounds down through Type IA at 300, Type II at 225, and Type III at 200. Pick a rating with margin above your loaded weight.

Why doesn’t a 24-foot ladder reach 24 feet? The two sections overlap when extended, so the working height is less than the labeled length. Always plan around usable reach and buy a size taller than you think you need so you’re never standing on the top rungs.

What angle should the ladder sit at? Set it on a level, stable base at a 65 to 75-degree angle — about a 1:4 ratio. One foot of base distance for every four feet of height.

How do I handle a slope or uneven ground? Look to a leveling model. The LevelSafe Pro levelers adapt to uneven terrain automatically when you set the ladder down, and each leveler extends up to 8.5 inches. That covers most real-world slope without improvising a footing.

Can I use the base section by itself? On the fiberglass D-rung leveling models, yes. The base and fly sections easily separate to use the base section as a single ladder.