May 26, 2010
If you have an old masonry surface such as concrete, brick, or stone that looks really green, black or both I am going to share with you how you can clean them up. There are various methods for each surface type so I am going to discuss them all.
First you have to gather the equipment needed to complete this task. You are going to need a empty 5 gallon pail, stainless steel bug sprayer, access to water with a hose, muriatic acid or some other masonry cleaner, a scrub brush, steel wire brush, protective gear waterproof gear, gloves,jacket, hood, pants, boots and most importantly eye protection, acid does not feel good in your eyes. Lastly you will need a good gas powered pressure washer you can buy one for around $300.00 or just rent one for a day.
Dirty brick and stone walls can be handles a few different ways you can use muriatic acid or a less dangerous cleaner such as sure clean or a pressure washer or both together. If you opt to use a cleaner wet the surface first with a hose. Next apply cleaner with a hard plastic bristle brush or use the bug sprayer to apply it. Be sure to dilute the cleaner with water first to make it safer to use, follow the instructions on the cleaner you are using. Try not to breath in the fumes from the cleaner either, it can make you very dizzy and vomit. In really dirty area you may have to scrub really hard or use a steel wire brush moderately over the affected area. If you are using acid it should bubble up on dirty area right away but it doesn’t work all that well on moss. After you have scrubbed the wall down hose it off or I recommend using a pressure washer with the fan tip to clean it off. A pressure washer itself is capable of cleaning most of the surfaces if done properly, but don’t get too close with the tip you blast a hole in your brick or mortar joints if they are aged.
If you are cleaning concrete it can be done much the same way as what you did the brick and stone wall. However you must be more consistent with your pressure washer. If not you will easily see where you have wash and where you have not sometimes giving your concrete an ugly striped look.
If you have an old sandstone surface such as a porch or steps that are flat there is another method you should use to clean them. For this project you will need a rubbing stone or another piece of sandstone that is about the same hardness. This does require some back breaking work but you will be very happy with the results when you are done. Take your rubbing stone a rub it all over the surface till you get a nice sandy grit all over the surface, in dirtier area you may have to scrub a little harder. Once complete simply sweep the surface or wash it off with a hose. Do not use acid or a pressure washer on sandstone surfaces, they are very easily damaged.
If you are unsure of how to complete this task you should hire a qualified mason or pressure washing contractor to take care of this for you. Working with acid and pressure washers can be dangerous for both you and the people around you. If you are not careful you can easily damage surfaces if you do not clean them properly.