Best Extension Ladder for Roof Work: Type, Size and Duty Rating

How to pick a ladder that reaches the roof with 3 feet to spare, carries you and your materials, and stays put on the ground and the eave.

For getting onto a roof, the best ladder is a fiberglass extension ladder long enough to extend 3 feet above the eave at the correct angle, with a duty rating that covers your weight plus everything you carry. Multi-position and telescoping ladders are useful around the house, but few of them reach a two-storey eave with that 3 feet to spare.

Below, the ladder types and accessories are compared, and the ladder size for a one-storey and a two-storey eave is worked out using the 4-to-1 angle rule.

Compared by type

Pros and cons describe each type from its specifications; this is not a hands-on product test. As an Amazon Associate we earn from qualifying purchases.

Fiberglass extension ladder

Best for: Regular roof access on one- and two-storey homes. Check: Duty rating (Type IA 300 lb or IAA 375 lb) and the maximum working length.

Pros

Cons

Multi-position (articulating) ladder

Best for: Single-storey eaves, stairs and indoor work. Check: Maximum extension-ladder height and duty rating.

Pros

Cons

Telescoping ladder

Best for: Occasional single-storey access where storage space is tight. Check: EN 131 or ANSI certification and the fully extended length.

Pros

Cons

Ladder stabilizer or standoff

Best for: Keeping the ladder off the gutter and widening its top. Check: Arm span and whether it bears on the wall or the roof.

Pros

Cons

Ladder leveler (leg extension)

Best for: Sloped yards, steps and flower beds at the foot of the ladder. Check: Which ladder brands and rail sizes it fits.

Pros

Cons

What size ladder reaches your roof

Set the foot of the ladder one foot out from the wall for every four feet of height to the eave (the 4-to-1 rule), and extend the rails at least 3 feet above the eave so there is something to hold as you step off. Extension ladder sections also overlap — at least 3 feet on ladders up to 36 feet — so the ladder's nominal size is longer than its reach.

Worked example: Single-storey (10 ft eave) and two-storey (19 ft eave)

  1. 10 ft eave: foot 2.5 ft from the wall; rail length to the eave 10.3 ft; plus 3 ft above = 13.3 ft
  2. Add 3 ft of section overlap → a 20 ft extension ladder
  3. 19 ft eave: foot 4.8 ft out; rail length 19.6 ft; plus 3 ft above = 22.6 ft
  4. Add 3 ft of overlap → a 28 ft extension ladder

A 20 ft ladder for a typical single-storey eave and about 28 ft for a two-storey eave — confirm against the maximum working length printed on the ladder's label.

Measure the eave height directly, or work it out from the wall height and the overhang with the roof pitch calculator. Once you are on a pitched roof, the roof jacks guide and the safety harness guide cover the rest of the setup.

Duty ratings

ANSI ladder duty ratings (the load includes you, your clothing, tools and materials)
TypeRated loadSuits
IAA375 lbProfessional roofers carrying bundles
IA300 lbContractors and heavier DIY loads
I250 lbLight trade and DIY use
II225 lbLight DIY
III200 lbHousehold tasks only

A bundle of architectural shingles typically weighs 60 to 80 lb, so anyone carrying bundles up a ladder should buy Type IA or IAA. The shingle calculator counts the bundles for your roof.

What to look for

Safety notes

Frequently asked questions

What is the best ladder for roof work?

A fiberglass extension ladder rated Type IA (300 lb) or IAA (375 lb), long enough to extend 3 feet above the eave at a 4-to-1 angle. Add a standoff or stabilizer so it bears on the wall or roof instead of the gutter.

What size ladder do I need for a two-storey roof?

For an eave around 18 to 20 feet high, a 24 ft to 28 ft extension ladder is typical once you allow for the angle, 3 feet above the eave and the section overlap. Check the maximum working length on the label.

Is fiberglass or aluminium better for a roofing ladder?

Fiberglass, because it does not conduct electricity and most roof edges have a service line nearby. Aluminium is lighter and cheaper but should be kept well clear of any power line.

How far should a ladder extend above the roof?

At least 3 feet above the point where it rests on the eave, so you have rails to hold as you step on and off the roof.

Can a multi-position ladder reach a roof?

For many single-storey eaves, yes, in its extension mode. Few models reach a two-storey eave with 3 feet to spare; check the maximum extension height before buying one for roof access.