What Size Ladder To Get On Roof

What Size Ladder To Get On Roof

These days, ladders are available in an array of sizes, shapes, and with some amazing features that make your job easy and safe to perform. Hence it is common to ask what size ladder to get on the roof?

Well, for a single-story building, a 15 to 18 feet ladder will just work fine. And for a double-story building, a 20 to 22 feet ladder is recommended.

One Story Ladders
Werner D1116-2 Extension-ladder16 Feet
Ohuhu Telescoping Ladder15.5 Feet
Two Story Ladders
Louisville AE2220 Extension Ladder20 Feet
Z6 Aluminum Telescopic Ladder20 Feet

Also remember, a sturdy ladder will provide you easy access to roof slopes. The different varieties of ladders available today along with various supporting accessories like non-slip rungs, gutter guards, and non-slip hooks do make a difference if you want to complete a roofing job quickly and efficiently.

What Size Ladder To Get On Roof: Calculation And Things To Remember

As ladders are available in various lengths and sizes, before getting one you must know the required length of the ladder to reach the roof.

What Size Ladder To Get On Roof

The following points will help you to purchase a ladder that is not too tall or too short and will help you complete your work safely.

• An extension ladder should be a few feet taller than the roof height that you need to reach. Always remember that 4-rungs from the top of the extension ladder would be the safe standing level.

If you step above this, there is a risk of tipping and the ladder may lose its balance. A step ladder is stable and safe only when used to the top two feet or the 2nd to the last step.

• The ladders should be placed at the right angle for which you need to follow the 4:1 ratio rule.

• An extension of at least three feet is required when the ladder rests against the roofline. This extension is measured beyond the topmost supporting point.

• Remember that the ladder’s working height will not be equal to its length. Also, when you set up the ladder at an inclination, its working height will reduce.

• So, while purchasing an extension ladder for roofing work make sure that it is at least 5 to 6 feet longer than the uppermost point against which it is resting.

The 4:1 Pitch Calculation

Don’t place a ladder’s angle too steep or spanned too far away from the work area. Follow the ladder’s recommended angle guides for ladder safety.

Use the 1:4 ratio to ensure a stable working platform. Place the base of the ladder 1 foot away of whatever it leans against for every 4 feet of height to the point where the ladder contacts at the top.

The Size of Ladder You Need for a One-Story Building

If you want to access the roof of a single-story building such as a bungalow, you can use a two-section extension ladder or a stepladder.

If you want to clean the gutter, then it is 3.3 meters from the ground in a single-story building. The extension ladder height of 3.95 meters would be the right choice. A combination ladder that merges the features of a staircase ladder and a stepladder is also ideal for this job.

For projects like a roof inspection or roof repair, you need a ladder of height 16 feet. As you would be spending a substantial amount of time on a ladder for doing such jobs, the ladder should be made of sturdy material.

The recommended ladder for a single-story building is Werner D1116-2 Extension-ladder.

Werner D1116-2 Extension-ladder
Werner D1116-2 Extension-ladder 

It is light-weight and easy to maneuver. It is also reasonably priced and highly durable. It is a great product for any home.

The best telescopic roof ladder perfect for a single-story building is the Ohuhu Telescopic ladder.

Ohuhu Telescopic Ladder
Ohuhu Telescopic Ladder 

The modern and progressive design is sure to impress you. High-quality aluminum alloy is used to craft this premium product. This ensures it is incredibly lightweight.

The non-slip end caps help in holding the ladder firmly in place. It is versatile and ideal for those who have limited storage space.

Related Post:

How To Stabilize Ladder On Roof – Detail Information


The Size of the Ladder You need for an Average 2 Story Building

The average height of the ceilings in a two-story house will be around 2.35 meters. The distance from the ground level to the eaves would be the height of 2 full rooms that is 2.35 x 2 = 4.7 meters.

And since ladder length is consumed during the placement, the ladder 1 meters to 1.5 meters longer than the roof height to provide perfect working height.

So, an extension ladder that can be extended to 7 meters would be perfect for the job.

When we talk about extension ladders, one of the best choices would be Louisville 20 Ft Extension Ladder. The ladder stands at 20 feet, a sizable height required to carry out roof jobs on a 2-story building.

Louisville Extension Ladder
Louisville Ladder

It has a load capacity of 300 pounds, which means you can safely step on it along with few tools.


The other best choice would be the World Good Telescopic ladder. This telescoping Extension Ladder is made of durable aluminum alloy. The bearing weight is 330 pounds.

World Good Telescopic ladder
World Good Telescopic ladder

The full extended length is 20.5 feet and when retracted it is 3.7 feet. When it is not being used, the ladder can be folded and stored conveniently in a small space.

How to Get the Pitch Right For a 2-Storey Building?

The average height of a two-floor house is six meters in height. So, the distance at which the base has to be placed from the wall would be about 1.5 meters.

It is recommended that the ladder top is about 90 cm beyond the edge of the roof. In case, the pitch is not right then there is a risk of slipping or the ladder might tip away from the surface of the wall.

The ladder must be inclined at an angle of 75° or follow the 4:1 ratio which means for every 4 feet of ladder height the distance of it from the base should be 1 foot away.

Assuming the following measurements for a 2-story building – Height = 6 meters, Base = 1.5 meters. The ladder length would be:

Z2 = X2 + Y2 = 62 + 1.52 = 38.25

Z = √38.25 ≈ 6.20 m approximately. To this add 1 meter that takes into account the extension needed beyond the edge of the roof. So, you need a ladder that is of height around 6.5 to 7 meters for a 2-story building. Similarly, you can calculate for a single-story house, which would be approximately 5.5 to 6 meters.


How Do You Climb a Ladder to Reach the Roof?

Homeowners need to occasionally access the roof for various purposes. Climbing a ladder up and down can be dangerous, especially you want to access the roof of a 2-story or a much higher building.

So, while using a ladder, it is necessary to use safety accessories, especially if you are working at heights. Use the right accessories like a stabilizer, leveler and anti-slip products to provide a stable platform.

The stabilizers avoid feet of the ladder from sliding away, especially on smooth surfaces or stops it from sinking into the ground.

You need to follow certain safety measures:

  • Balance your body in the center of the side rails.
  • Follow 3-point contact. Either keep one hand and two feet or one foot and two hands always on the ladder.
  • Always use footwear that is in good condition. Clean them, if it is covered with snow, grease, mud, or water.
  • Make sure to place your feet firmly on every rung.
  • If you are using an extension ladder to access the roof then be cautious while gripping or stepping on the locks.
  • Most of the ladders are designed for a single person. So, before using make sure that the individual using it steps off the ladder.
  • Ties or harnesses should not interfere while climbing the ladder.
  • Climbing down from the roof is merely revering your steps on the ladder while holding the top end firmly.

Safety Precautions

Climbing a ladder to reach the roof is not an easy task. We keep hearing the terrible news about the accidents that occur while climbing the roof. Falls from a height are one of the leading causes of mortality and in the past few years, about 43% of such falls occurred while using a ladder. So, adhering to certain safety measures can stop such accidents. These are:

  • Unnecessary Walking on the Roof
  • Step Carefully on the roof. Avoid stepping on the brittle and rotted roofing material.
  • Wear appropriate clothing. Use dry and clean rubber-soled footwear that also provides ankle support.
  • Get help from a family member or friend while trying to access the roof.
  • Stand properly as safe weight distribution between ladder, roof and you are very important.

Mistakes to Avoid

Dips in the ground

In the above calculation, we considered the ground to be flat. However, in reality, there may be bumps and dips on the ground.

You make use of a spirit level in order to know the difference in the level or it is best to use a leveler that ensures the ladder is in level with the ground.

One of the recommended levelers with good reviews is the ProVision Ladder Leveler.

ProVision Ladder Leveler
ProVision Ladder Leveler


So There it is. The answer to the most commonly asked question what size ladder to get on roof.

Working on ladders is a dangerous business, especially when it is about the transition from ladder to the roof, as falls are likely to occur. So, a proper ladder access system is quite important to make such a transition safe and avoid accidents.

Take all the safety measures to avoid any kind of mishaps. Also, check all your equipment before climbing the ladder so that you have all that you need once you reach the roof.

Good luck and stay safe!