House Grail is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

How to Pressure Wash a Roof – 10 Useful Tips

Man standing on ladder and cleaning house metal roof with high pressure washer

Roofs are a critical component of any home. They are exposed to sunlight, leaves, water, wind, algae, and animals on a regular basis. Over time, roofs can get dirty, clogged up with debris, and covered in grime. To help keep your roof as healthy as possible, it could be necessary to pressure wash the roof to rid it of damaging materials.

However, pressure washing a roof can be a tricky job. In the wrong situations, it can even be dangerous. Pressure washing a roof is not a job you want to rush into or do on a whim. You should take time to learn some tricks and examine the situation before continuing.

Here are ten tips on how to pressure wash a roof that will keep you safe and prevent your roof from being damaged in the process.

divider 7

The 10 Useful Tips on How to Pressure Wash a Roof

1. Inspect the Roof Before Starting

Before getting onto your roof, you need to give the roof a good look over. You want to check for soft spots, slippery patches, piles of leaves or sticks, and damaged shingles. Pressure washing a roof can be dangerous and you want to make sure that you know the roof inside and out before climbing up and walking around. It will only take one wet leaf or one unsecured spot to send you tumbling to the ground.

man painting metal roof
Image By: tkemot, Shutterstock

2. Apply Detergent First

After inspecting the roof, you should try and apply some detergent to the roof. You can use a soap shooter or an attachment for your hose to spray the roof with soap and detergent. From the ground, angle the spray and soak the roof as much as possible, and let the soap sit. The detergent will help kill algae and break up entrenched grime. This will have two positive effects. First, it will help make the roof safer when you get up there by eliminating some slippery spots. Second, it will make it easier to wash the grime and algae away with a low-pressure spray. You must wait for the roof to dry before climbing up and pressure washing the rest.

3. Wash in Sections

When inspecting the roof, make a plan to clean certain sections at a time. You do not need to do the whole roof at once. In fact, doing the entire roof is difficult because you need to avoid wet patches and keep a dry, safe path open back to the ladder at all times. Break the roof into chunks and wash each one at a time to make the job more digestible and safer to complete.

man cleaning the solar panel
Image Credit: Maddy Bris, Pixabay

4. Never Walk on a Wet Roof

Never ever walk over wet tiles or shingles. A wet roof can be extremely slippery. There can be leaves, algae, or standing water that can cause you to slip with one wrong step. That is why it is important to wash in sections. You should always leave a dry patch to stand on and a dry pathway back to the ladder so you can get down whenever you need to.

5. Do Not Wash Yourself into a Corner

One of the most common and dangerous mistakes that people make when pressure washing a roof is washing themselves into a corner. Many people will start washing and get into the groove only to realize they are on the opposite side of the roof with no dry pathway back to the ladder. This will leave people with two options. Brave the wet roof to get back to the ladder, which is very dangerous and ill-advised, or wait for the roof to dry. Neither option is good. The best thing to do is to leave yourself a pathway back to the ladder that is always clear and open.

man cleaning chimney
Image Credit: Couperfield, Shutterstock

6. Always Spray Downward, Never Upward

When washing the roof, always wash downwards. That means you should always be pointing the wand downward toward the roofline and never up toward the ridgeline. This is important for two reasons. First, if you spray upward, you can accidentally get water under your shingles. This is bad for the health of the roof. If you use too much pressure, you can actually blow the shingles off, causing damage to the roof. Second, spraying upward can cause you to lose your balance. The force of the water will push you backwards towards the roofline, which is very unsafe and could lead to an accident. It is more stable to spray downward.

7. Use a Low-Pressure Setting

You should always use a low setting on your pressure washer when pressure washing a roof. Too much pressure can damage your shingles or cause too much force, leaving you off balance. High settings on a pressure washer are more than powerful enough to blow shingles off a roof, which will leave holes and gaps that can let water into your home. Try to use the lowest possible settings for the best results.

Pressure Wash
Image Credit: Pressure Wash, Mark Schellhase, Wikimedia Commons CC SA 3.0 Unported

8. Move the Wand to Increase the Pressure

If you are having a hard time getting a spot off a roof, you will have the urge to up the pressure. Do not turn up the pressure on your machine. Instead, move the wand closer to the roof. You can move the wand until it is just a few inches from the roof. The decreased distance will help increase the power of the wand without upping the pressure to a point where you can accidentally damage your roof.

9. Keep an Eye Out For Damage

When you are on the roof and washing, you should always be keeping an eye out for damage. If you are pressure washing a shingle roof, it is possible that you could accidentally peel shingles off the roof. If you start damaging shingles and ripping up parts of the roof with your pressure washer, stop immediately. Damaged spots on the roof can also be unsafe to walk across, so you need to keep an eye on your feet to ensure that you can always keep your footing and your balance.

man cleaning the roof
Image Credit: Greg McGill, Shutterstock

10. Always Keep Safety First

Doing anything on a roof can be very dangerous. Falling off a roof can lead to serious injuries and even death. If you feel uncomfortable on the roof for any reason, you need to get down right away. There is no shame in admitting that something is too far out of your comfort range or skill level. It is not worth risking your health to complete a job that you are unsure about. Some roofs are steeper than others. Some roofs have a lot of leaves or damage that was unseen before the job. You can always tap out.

Keep an eye on your feet. Never lean over the roofline. Never wash upwards. Avoid damaged and slippery spots. Never walk on a wet roof. Wear shoes with a lot of grip. These tips will help keep you as safe as possible during your job. Safety is more important than having a clean roof. You can always hire a professional if you feel overwhelmed.

divider 1


Pressure washing a roof can be daunting, but it is doable. There are some important tips that you should follow before and during your job to ensure the best results and the maximum level of safety. Taking these tips to heart will vastly improve the experience you have while pressure washing your roof by avoiding damage and helping you feel comfortable on the job.

Featured Image Credit: Ronstik, Shutterstock


Related posts

OUR categories

Project ideas

Hand & power tools