How To Fix and Paint a Damp Garden Wall (Garden Walls Solved)

  • By: homeshacks
  • Date: December 27, 2022
  • Time to read: 6 min.

If you have a garden wall that is starting to show signs of dampness, don’t worry, there is a fix! In this article, we will show you how to repair and paint a damp garden wall.

The first step is to remove any loose or flaking paint from the wall. Use a wire brush or a scraper to remove the paint, and make sure to wear gloves to protect your hands. Once the loose paint has been removed, it is time to fix any cracks in the wall. Use a concrete repair compound to fill in any cracks, and allow the compound to dry completely. Once the cracks have been fixed, it is time to paint!

There are techniques that you can employ to make it safe for painting, but generally speaking, this type of situation calls for another solution such as applying and curing a new layer of waterproof membrane.

If you don’t use KILZ or another waterproof primer, then there is a chance that moisture can soak through your exterior paint and cause it to begin peeling within the first year.

Also, if you just go ahead and paint over your fence or wall without making sure that all of its surfaces are dry, then the paint will start cracking and peeling within a short amount of time. However, if you really want to paint a damp exterior wall or you have no other choice then read on for some important information that could save you money and headaches down the road.

One of the best ways of preparing a damp exterior wall is to “dry it out” by allowing the moisture in the wall to evaporate. This is faster than removing the water completely by extracting it, but it does mean that you must be patient.

KILZ Primer, Waterproofing and Sealing

If all of the moisture has not evaporated after about four weeks then painting should be postponed. If you’re in a hurry to finish the job, it’s fine to go ahead and paint now, but you must prime the wall first. In this case, using a KILZ Primer does the perfect job!

KILZ is waterproof so if any moisture still remains in the exterior wall, it will not soak through to whatever is behind the wall. It will just sit on top of the surface for a while.

KILZ Primer can be purchased at any hardware store or here at Amazon. It essentially seals off your exterior wall so that moisture cannot seep through to the inside. It will also keep out insects, mold, and mildew that can be carried behind your walls in the air or on people’s clothing.

Damp Wooden/Lumber Exterior Wall

If your exterior wall was made out of wood or pressure-treated lumber then all you need to do is install 2-4″ sections of PVC piping horizontally around the wall, then use detachable aluminum flanges to fasten them to it. Drill about 1/2″ holes every 4 inches or so around these pipes to let water seep out through them, then connect them together using a T-fitting.

If you have a garden hose, then you can direct the water to a safe place where it won’t cause any damage. You could also install gutters and downspouts to help funnel the water away from your exterior wall.

Once you have taken care of the drainage, it’s time to paint! Make sure that all of the lumber is completely dry before you start painting, and use good quality wood paint or stainer!

Damp Brick Or Stone Exterior Wall

If your exterior wall was made out of brick or stone, then you’ll have to drill 1/4″ – 3/8″ holes every 2-3 feet around the wall, depending on its size.

You can also let water flow out of your exterior wall by placing 1/2″-thick wooden dowels horizontally between bricks or stones that are located about 2 inches apart. You will then have to seal the cracks with a good quality sealant like this one from Amazon.

How do you paint rendered garden walls?

If you paint only the face of the rendered wall it is possible that moss will start to grow on the damp surface where they are protected. If this happens then you might have to strip all the old paint off and start again. However, if you coat the entire garden wall with waterproofing masonry paint, which also provides an even color, then you should get no problem with moss growth.

To paint the rendered garden wall you need to give it a good scrub down first, removing all grit and flaking paint – use an old stiff-bristled brush for this job. The best way to remove loose bits of cement is to scratch it off with a strong metal nail file or an old chisel. You should then prime the wall with several coats of bitumen-based primer before applying your color coat.

Don’t forget to smooth out any ridges left by the trowel when you first laid it by rubbing them down with a damp sponge – make sure you allow plenty of time for this stage as it’s very easy to damage the fresh paint if you rush it. You should also watch out for any coarse bits of cement poking through the final plaster coat, especially after rain when they are likely to become moist and stand out so much that you might think they are delaminating, but more often than not they are just drying off. 

If this happens, just rub them down with a little more mortar mix and smooth them out. Really tenacious bits of cement can be dealt with by cutting them off flush to the wall using a sharp knife or trowel, but make sure you don’t damage the render – try scraping the area first with your nail file, if it doesn’t come up easily then you’re better off to leave it alone.

Best Time To Paint Rendered Garden Wall?

The best time to paint a rendered garden wall is when the weather is dry and settled – this will allow you to give your final coat an extra few days to harden before you bring out all your hanging baskets and patio furniture. It’s also worth pointing out that if you build up several coats of paint on your wall the surface will become very smooth and you may find that some of your paint won’t stick to it. If this happens just rub a little more mortar mix into the surface with a sponge and leave it for another few days to dry out before you repaint.

Do’s And Don’t Of Painting Render:

  • Do give each coat plenty of time to dry properly – you can help the drying process by opening up all your windows and doors.
  • Don’t use too much water when you are mixing up your mortar or render – try not to make it too wet as if it’s too runny then this will seep through any porous renders. This can cause damage further down the wall. It’s also worth bearing in mind that the faster you apply your render coat the better, so don’t stop to chat with your neighbor for too long – this will allow it to set before you move on to the next section.


Of course, each type of siding material has its own unique challenges when it comes to trying to drain water out of an exterior wall with holes drilled into it. For example, cedar shakes will need to be removed and replaced due to rot, while vinyl siding will need to be cut away in sections so that it can be resealed back together.

We hope this article has cleared up a few if not all unanswered questions!

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