How to Restore and Protect a Concrete Wall - 2

The previous post of this series discussed the need to restore and protect an old concrete wall and the possible steps to take to address that need.

Clear the Wall of Obstruction

In order for you to quickly do the job of restoring and protecting the concrete wall, you need to clear it from debris and other obstructions. Obstructions may include your plants and other garden structures. Having plants at the wall or vines growing on a trellis mounted to the wall may pose some challenges.

Plants growing on garden pots or trays near the wall need to be relocated.

If you have a vigorous vine growing on the trellis that's mounted on the wall, now is be the best time to prune it back really hard. This accomplishes two things. First, the cleared area allows you to move about and work freely on the wall, and second, there is lesser chance of getting some fresh concrete or paint on the plants.

Parts of vines that cannot be cut or pruned should be moved out of the way.

Here, I have the Curtain Ivy (aka Millionaire's Vines) plants which are generally admired for their dangling threads (aerial roots). What I did was to tie together the threads in a bunch with a tie wire as shown below.

Then hang the bundled threads up on the trellis to move them out of the way.

Now is also the time to remove structures that are no longer needed or need to be replaced. Remove debris like old rusty nails or screws still embedded on the wall.

The small wire trellis I built needed to be replaced with a bigger one and so I removed the trellis brackets. Here, I'm tapping one with a hammer.

Then used the hammer's claw to pull out the nail.

For tools, you generally would just need to a claw hammer or a small crowbar to get rid of debris still attached to the wall.

Clean the Soiled Areas

After the wall has been reasonably cleared of obstruction, you may now clean the soiled areas. For this task, you will need a wire brush and a wide paint brush.

With the wire brush, scrape any visible moss and soiling on the wall as shown below.

You can see the effectiveness of the wire brush is in removing surface dirt, mould and moss. Mould on the wall takes on a grayish purple color. Use the wide paint brush to remove fine concrete particles and dust that results from the wire brush scraping.

Be careful in using the wire brush as it can cause cuts and abrasions. Wear a pair of garden gloves for extended work. Use a consistent sideways motion to prevent accidents.

Soil, sand and concrete particles may break out in the process of scraping the concrete surface so wear a hat. Wear a pair of safety goggles to protect your eyes.

Treat the Concrete Surface with Anti-Mould Solution

For any remaining mould or moss deep in the concrete that cannot be removed by scraping, apply an anti-mould solution like the one shown below.

Pour the anti-mould solution in a container that's wide enough for your paintbrush. Dip the paintbrush in the solution and apply it on the concrete wall surface with a smooth brushing motion.

Depending on porosity of the concrete, the solution may seem to quickly "disappear" as the surface quickly absorbs the solution. Dribbling the paintbrush on the wall will create suds as shown below.

Some anti-mould solution like the one I used advice against applying it on windy days so be sure to read the label.

Don't worry if the solution's color becomes a bit greenish on the wall. This usually happens where there is heavy moss growth.

Shown below is the concrete wall after scraping and treating with the anti-mould solution. You'll notice that the part on the right had heavy moss growth.

Although some concrete contractors may skip this treatment, it's a worthwhile job to avoid recurring mold as well as to ensure a good concrete resurfacing and finishing.

The next post will discuss finishing and painting.

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