How To Clean A Slate Patio [Step By Step Guide]

Slate is a fine-grained and durable rock, which is why they are a great addition to your patio. However, they tend to collect grime and lose their expensive look over time. If you are curious about how to clean your slate patio, this article is for you.

We've done the research, and here is what we've learned!

You can clean a slate patio using these two main methods:

Mild detergent soap with water method

  1. Sweep using a soft bristle broom
  2. Mix a mild detergent with water
  3. Brush the slate with a soft-bristled brush
  4. Rinse with water
  5. Let it dry
  6. Apply sealer

Pressure Washer Method

  1. Clear the area
  2. Connect to a water supply
  3. Pressure wash the patio
  4. Let it dry
  5. Apply Sealer

Slate is known to be durable and is an excellent addition to your patio. Despite being robust, cleaning it should still be handled with care. This post will discuss how to maintain your slate patio, the aftercare, and what other methods you can opt for to clean your slate patio. Let's dive right in!

Blue wicker chair and wicker table in the middle of a slate patio with plants and trees in beds and pots. Taken on a sunny summer day with nobody in the shot., How To Clean A Slate Patio [Step By Step Guide]

How Do You Clean A Slate Patio?

Slate has been used for a long time, primarily outside, because of its sleek appearance that goes well with outdoor settings, especially when damp.

Large table and chairs on slate patio with Mediterranean plants in a back garden

Even though it may seem slippery when wet, slate has impermeable properties, making it non-slippery.

Slate comes in different colors and designs. Its durability makes it great as flooring. However, they tend to accumulate grime over time and begin looking dull.

Sometimes when exposed to moisture so often, algae start to form, making it slippery.

Cleaning a slate patio is easy and simple. Several methods are available to tend a dull slate patio that will be convenient for you. The two main ways are cleaning it using a mild detergent soap mix, water, and a pressure washer.

Mild Detergent Soap And Water Method

This method is easy; most materials are found in your household. You can use mild soap and water when your patio needs occasional and light cleaning.

Here is a  guide on how to clean a slate patio using mild soap and water:

What you'll need

  • Soft bristle broom
  • Mild soap
  • Baking soda
  • Bucket of water
  • Garden hose
  • Soft-bristled brush
  • Sealer

Step 1: Sweep using a soft bristle broom

Clean the slate patio using a soft-bristled broom to sweep away dust and debris. It will make cleaning so much easier when it is time for mopping.

Step 2: Mix mild detergent with water

Use mild soap mixed with a bucket of water. Too much soap can be difficult to remove, and exposing the slate stone to harsh chemicals can deteriorate it.

Step 3: Brush the slate with a soft-bristled brush

Mop the slate with a soft-bristled brush to remove stubborn grime and bring out the stone's unique look. For stains, you can apply baking soda and scrub the area.

Step 4: Rinse with water

Get your garden hose and thoroughly rinse the patio with water after getting rid of the accumulated dirt and soapy water.

Step 5: Let it dry

Let your patio dry under the sun. It is best when it is scorching hot to speed up the drying time.

Step 6: Apply sealer

Applying a sealer is optional. However, use a sealer to add that glossy, wet look to the slate stone. A sealer will help maintain the natural look of the stone.

It's also effortless to apply with the use of a roller brush. Apply when the slate patio has dried.

Click here to see this slate sealer on Amazon.

Pressure Washer Method

This method is probably the easiest because it does not require a lot of materials and is quicker. When using a pressure washer, it is essential to know which type of nozzle is best when cleaning a slate patio.

This method is best if grime is stubborn to remove using the mild soap and water method.

If you're unsure what nozzle to use, start with a Green 25° nozzle. This nozzle is almost an all-around nozzle because it gives the right amount of pressure to eliminate grime and won't damage your slate patio.

The ideal nozzle, especially for a wider spread, is a White 40° pressure washer nozzle. This nozzle is perfect for wide settings and is suitable for delicate surfaces because it applies low pressure to prevent damage.

Here is a detailed, step-by-step guide on how to clean a slate patio using a pressure washer.

What you'll need

  • Floor scrub brush/Soft bristle broom
  • Pressure washer
  • Water

Step 1: Clear the area

Sweep the area using a soft bristle broom or a handle floor brush to remove debris from the surface.

Step 2: Connect to a water supply.

Prepare your pressure washer and connect it to a water supply through a tap or a bucket, whatever is convenient.

Step 3: Pressure wash the patio

Once the pressure washer is ready with the proper type of nozzle, wash the slate patio to eliminate algae and molds. Adjust pressure depending on your liking. 

Step 4: Let it dry

Let the area dry for 24 to 48 hours. Drying time may vary depending on the weather.

Step 5: Apply Sealer

Lastly, apply a sealer. This will help maintain the slate and prevents it from deteriorating over time.

Can You Clean A Slate Patio With Vinegar?

You can't clean a slate material with vinegar.

Although vinegar is considered a natural cleaner, the acidic property of vinegar can cause a chemical reaction that will damage the stone, which is why it is not advisable to use it.

If the stain is tough to remove and you want something natural, opt for baking soda. Baking soda and water will aid in getting rid of light stains and grime on the slate patio.

Do You Need To Seal Your Slate Patio?

Natural slate tile paving

A slate patio needs cleaning once in a while to maintain its fresh look. Slate may deteriorate over time due to weather and excessive exposure to moisture.

Applying sealer to your slate tiles may reduce tending time and effort.

Sealer can also protect the stone's natural finish while enhancing the anti-slip property of the slate. It will also prevent it from getting dull quickly over time.

How Much Does It Cost To Install A Slate Patio?

Shiny Flagstone Mosaic Tiled Texture Ornamental Background

Slate installation on a wide area costs around $10,400 on average. The low average cost is around $7,200 and can go as high as $32,000.

When it comes to slate installation on a patio, it will cost you around $9 to $40 per square foot. Price may vary depending on labor, landscape preparation, the quality of the material, and the brand.

Pros And Cons Of Using Slate For Your Patio

Rustic Grey and brown slate landscaping rocks for sale at a garden store or construction supply.

Slate is an ideal tiling material for outdoor settings because of its durability and anti-slip qualities.

Even though it has many positive attributes, it can also possess some undesirable traits that some people may not like. Let us weigh the pros and cons of using slate.

Pros Of Using Slate On Patio

Here are some of the pros of using slate on your patio.


Slate is known for its durability, making it a perfect tilling, especially in outdoor settings. It does not crack, break or scratch easily.

Long lifespan

Another great quality of slate is it is long-lasting. With proper maintenance and sealing, it can withstand environmental deterioration.


Slate is used in surface tilling and roofing because it is thinner and lighter than other materials. Slate can also be used indoors and looks great in bathroom and kitchen settings because of its modern look.


One of the excellent characteristics of a slate is it is not slippery even when wet. Its non-porous trait is also beneficial, so it does not attract moisture easily.

Cons Of Using Slate On Patio

Here are some of the cons of using slate on your patio:


Slate can cost around $4 to $10 per square foot. Professional installation adds $10-$15 per square foot.

Difficult to install

Installing slate requires special tools, so it may be difficult for DIYers to do it, and some preparations need to be done before adding it.

Challenging repair

The repair can be challenging because slate comes in unique and different looks. Finding the same design won't be easy in case of accidental damage.

Hard material

Slate material can be hard and sturdy, which is beneficial, but its rough texture can also be uncomfortable.

Due to its rough and sometimes uneven surface, it is also not suggested for use as flooring for young children and the elderly.

To Finish

Close-up of garden stone block paved walkway.

Slate is a great and durable material that adds value to your patio because of its bold and unique design. It does not require much maintenance than cleaning and sealing it once in a while.

Cleaning does not require much and can quickly be done in several ways on what is convenient for you. We hope this article has provided sufficient information on cleaning and maintaining your slate patio.

Want to read more? Check out these related articles below:

Pallet Of Flagstone: Cost, Weight, & Sq Ft Coverage?

Water Pooling On Patio Pavers – What To Do?

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