How to Remove Mold from a Patio Slab

What You'll Need
Scrub brush
Dish detergent
Wet vacuum
Face mask
Trisodium phosphate

A patio slab is prone to mold because it's resting outside on damp soil. Even if you have used landscaper’s fabric and sand mold will always find a way to attach itself to concrete. Once you locate mold on your patio slab it's imperative to remove it right away before it can spread to other areas of the home. The article below will show you how remove mold from a patio slab.

Step 1 – Broom the Patio Slab

Make sure you wear the rubber gloves and mask prior to getting started as mold can be harmful to your health. In a clean bucket combine one part of detergent to four parts of water. Make sure the detergent does not contain any ammonia. Locate the mold and pour half of the liquid on the patio slab. Use the broom and work the water and detergent mixture in to the area. This allows the mold to loosen its grasp on the concrete.

Step 2 – Mop it Down

Dump out the remaining water and soap and rinse out the bucket before filling it back up with clean water. Mop the patio slab thoroughly and allow it to air dry. Inspect the concrete to see what mold remains. This mold that remains is the active mold that allows it to spread.

Step 3 – Bleach It

Bleach will kill nearly anything. Mix bleach with water at a ratio of one part bleach to ten parts water. Pour the bleach water on to the patio slab over the mold. Scrub the area to loosen the mold, then suck it up with the vacuum. Mop the area as well to remove most of the water then allow it to dry. For particularly tough mold problems you can increase the strength of the solution by using more bleach to water. It is not recommended to use a solution that is equal parts bleach to water.

Step 4 - Trisodium Phosphate

Even though bleach will kill almost everything, there is a chance the mold may remain. To ensure complete removal mix a bleach and water solution as you did previously but to it add ¼-cup of trisodium phosphate to every 2 gallons of water and bleach. Trisodium phosphate is a dangerous chemical used to remove mold by killing the bacteria that causes it. This is a very potent mixture so use very little of it. Dip a scrub brush in to the mixture and scrub the patio slab down completely and thoroughly. Use the wet vacuum to remove excess water and allow the patio slab to dry.

Step 5 – Preventative Measures

With the mold problem taken care of consider where the mold came from. If the patio slab gets hit with a lot of water or is in an area where water can become stagnant, consider creating a drain channel around the patio. You should also clean off the patio regularly when it rains. Remove leaves as soon as possible as any biological that decomposes can cause mold.