If your house has a stone exterior, you might be wondering how to clean it properly to avoid damaging the stones. What type of brushes and cleaner work best? We've researched this for you. Here's what we learned.
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To clean a stone house exterior, you can choose from the following methods:
- Scrub using a sponge and a mixture of mild soap and water
- Soft wash using a pressurized hose
Do you need more information? Read on below and we'll give you step-by-step instructions and more tips to avoid damaging the stone.
How Do You Clean Natural Stone Outside?
Granite, marble, limestone - no matter what type of stone the exterior of your house is made of, its natural beauty and color will stand out when it's rid of dirt, dust, moss, and grime.
What's the best way to clean it? Here's how.
Cleaning With Soap And Water
This simple method of cleaning the house's stone exterior doesn't require any special tools. Everything you need is surely just around your home.
What you'll need:
- Bucket of warm water
- Gentle dish soap
- Large sponge
- Nylon brush
- Garden hose
What to do:
- Fill the bucket with warm water.
- Add a few drops of dish soap and mix (it doesn't need to be very foamy).
- Dip the sponge in the mixture and scrub the stone exterior one area at a time.
- Rinse the sponge with water using the garden hose before dipping again in the mixture and continue scrubbing.
- For parts with stubborn dirt, use a soft nylon brush.
- When done, use the garden hose for a thorough rinse.
Check out this video below for more cleaning information.
Soft Wash Using A Pressurized Hose
Using a pressurized hose will get the job done faster. However, you may still need to follow through with a nylon brush and soapy water for areas with stubborn dirt.
There are certain dangers in pressure washing exterior stones, but it can be done properly with the right pressure setting. Stone care experts advise—do not use a pressure washer with a pound-force per square inch (PSI) setting of above 1000.
When you buy a pressure washer, the maximum PSI is usually indicated in the product description. It is recommended to buy a product with adjustable pressure settings so you can use it for various cleaning tasks.
Take note, however, that this method is not advised if you are cleaning manufactured stone veneers. It can damage the masonry adhesives that are holding the stones together.
But for other types of natural stone exteriors, this method is very efficient. Here's how to do it.
What you'll need:
- Pressure washer
- Stone cleaner product
What to do:
- Use the pressure washer to rinse the stone surface
- Apply stone cleaner product according to the instructions
- Rinse thoroughly to ensure there's no product left
Do this on a nice warm day to ensure the stones will dry up well after washing.
Things To Avoid:
- Do not use brushes with wire bristles to avoid scratching the stones. Nylon brushes are okay to use.
- Avoid using a pressure sprayer if you're cleaning stone veneers. It can dig in between the stone sidings and into the concrete or masonry adhesive that's holding the stones together.
- Avoid using strong chemicals and acidic cleaners on the stones to avoid altering the color and its natural look.
What Is The White Stuff On Stones?
The powdery white stuff that you sometimes see forming on the surface of stones is called efflorescence. These are naturally-occurring salts that are dissolved in groundwater and surfaces as it dries up, leaving chalk-like salts on the surface of the stones.
Efflorescence is a normal occurrence and can easily be removed by brushing and rinsing it away with water. To prevent it from resurfacing, ensure the stones are always dry with proper grading and dampproofing behind installations.
For stubborn efflorescence that keeps coming back, you can try using a product cleaner.
What Is The Best Cleaner To Use On Natural Stone?
We browsed through various sources of exterior stone care sites on the internet and we found out that the best and safest cleaner to use is plain water and mild soap.
If the problem is simple dust, dirt, and a bit of mildew, using a mixture of warm water and a few drops of dishwashing soap is enough to scrub out the surface dirt and restore its original color.
However, if the problem is a combination of dirt, grime, mildew, and heavy moss, it would be best to look for a cleaner that will not only help clean it faster but prevent it from coming back.
There are various products you can choose from that are specific for cleaning stones. In fact, some are even multi-purpose, so you can use them on other exterior parts of the house as well.
Does Vinegar Ruin Natural Stone?
Vinegar is considered an acid and is therefore not recommended as a natural stone cleaner. Why? It will cause etching on the surface, cause discoloration, penetrate the stone's pores, and can ruin the masonry adhesive that holds the stones together. Vinegar can eventually make the stone weak and brittle with repeated use.
This all has something to do with the potential hydrogen (pH) levels of these products. Vinegar has a pH level of 2-3 which can be damaging to stones. A typical stone cleaner has a pH level of 7-10 which is a significant difference from acids such as vinegar and lemon juice.
As an additional note, a mild dishwashing liquid has a pH level of 7-8 making it ideal for cleaning stones.
Can You Use Dawn On Natural Stone?
Yes, you can use Dawn dishwashing products for cleaning natural stones. Upon checking, we learned that it has a pH level of 8.7 to 9.3 which makes it safe for cleaning stones. This also means you do not need to use any protective gear on your hands when using it.
To make a cleaning solution, put a few drops of Dawn dishwashing in a gallon of water. Dip the sponge into the mixture and use it to wipe and scrub exterior stone walls. Rinse thoroughly after scrubbing.
Can You Use Bleach On Natural Stone?
Bleach is a known effective solution to kill moss and mildew, and is often used even on pavements and driveways with proper precautions.
If your stone exterior is growing heavy moss, this might be the first thing that comes to mind but take note, it's not the solution that's best for your stone exterior walls.
You might be wondering why? After all, bleach is not an acid and even has a pH balance of 11-13 which is common on commercial cleaning supplies.
The reason why bleach is not an ideal cleanser for natural stone is that it is too strong. It can cause discoloration, remove the stone's protective seal and penetrate the pores making the stone brittle.
Is Sealing Natural Stone Necessary?
After cleaning your stone house exterior, you might be wondering whether you should put some kind of sealer to help protect the stone from outside elements such as air pollution, rain, snow, and ice.
While it's not really required, many contractors agree that it's a recommended process to help preserve the integrity of the stone. After all, having stone exterior walls can be very expensive and you want to preserve its beauty as much as you can.
If your contractor didn't put a sealing product on your stones upon installation, you may want to have it sealed or you can do it yourself. Check out this video below for some insights.
If your contractor already put sealant but the stone seems to be absorbing moisture, it may be time to reapply it or use a different product. Some sealants can only last for a few years before it needs to be reapplied.
If you want to DIY sealing masonry, the first thing you need to do is to determine the type of stone you have and find a product that's suitable for it. You can check the product description for this.
Another thing you need to consider when buying the product is the color upon application. Some sealing products can stain your stones so you may want to use a clear one that only enhances the color of your stone and not alter it.
Thank you very much for reading through this article. We hope we were able to help you properly clean your house's exterior stones. To learn more about exterior stone care, check out these other articles below.