How To Keep Landscape Timbers From Rotting (Do These 4 Things!)

Ryan Womeldorf
by Ryan Womeldorf

If you have an outdoor project that you want to get completed, there is no doubt that landscape timbers can come in handy. These are versatile, durably constructed materials that are meant to hold up over time.

Unfortunately, they can also run into issues with rot. When constantly exposed to moisture, even treated timber can and will rot. The key is to keep it away from areas with a lot of moisture exposure and to keep the wood painted. The paint protects the timber from allowing the water to permeate the wood, which prevents rotting, bowing and even mold.

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What is Landscape Timber Used For?

If you are unfamiliar with landscape timber, you may not even really know what it is used for. These timbers are generally pretty small in nature – 3- to 6-inches at the most – and are either rounded or just straight boards.

Timbers can be used for walls, garden beds, small structures like sheds, steps, and even fencing. You would add landscape timbers to provide structural support for the project in question. The key to proper construction is to plan it out and ensure that there is little moisture in the area.

Landscape Timber Rot

Unfortunately, timber rot is a major challenge and frustration that faces homeowners using them. While the easy answer for combatting rot is to keep your timber away from high-moisture areas, it is not always that easy.

Preventing rot is important to your project. That is why it starts with a better understanding of why rot happens and following it up with preventative measures. Rot can destroy any type of wood that it comes into contact with if it is not properly prevented.

Treated Landscape Timber Can Rot

While it might seem like the simplest answer is to go with treated landscape timber, that is not going to really help. The reason being is that even treated landscape timber can rot due to a fungal attack. Fungi are microscopic organisms that move within the timber, eating it from the inside.

When there are fungal attacks on your landscape timber, it decays the wood from the inside, softening it. Whenever you are using landscape timber for a project, make sure to thoroughly inspect it for potential fungi damage. The last thing you want is to finish the project only for it to literally fall apart due to rotting and structural weakening.

Moisture Exposure

The biggest detriment to landscape timber is moisture exposure. Without being properly waterproofed, that timber can and will rot due to excessive moisture exposure. Wet rot is just as it sounds: a higher moisture content that does not eventually dry out.

Dry rot, on the other hand, is where moisture content hovers right around the 20% mark. Wet rot needs to be treated immediately as it could cause major damage and structural issues within your wooden structure. The bigger the structure, the more problematic that is.

It takes more than the presence of fungi and water to create rot, though. Those two things mix with warmth, oxygen, and a substrate (the wood in this instance) in order to create that rot.

How to Keep Landscape Timber from Rotting

Thankfully, there are a few different things that you can do to prevent rotting from occurring in your landscape timber. If you can waterproof the timber, all the better. But if you can’t, there are two methods, in particular, that should work just fine: moisture-free location and paint.

Limit Exposure to Moisture

This is perhaps the “easiest” method but it is in no way easy. The simple fact of the matter is that the outdoors are unpredictable. Rain and other moisture factors will rear their ugly head. By gauging the area in which you will be using the landscape timber, you can get a better idea of which spots get less exposure to moisture.

By putting your landscape timber in the areas that don’t get heavy moisture, you may be fine. Still, you run the risk of rot if those conditions change. Heavy rains, for instance, can always bring with it the threat of rot for your landscape timber.

Retaining Wall Moisture Barrier

If you don’t quite feel like leaving everything up to chance, you can install a retaining wall moisture barrier. You can aid the prevention of rot by making sure that your timber doesn’t come into direct contact with masonry or the ground.

Just make sure that your moisture barrier doesn’t have any cracks or gaps in the joints that could allow moisture in. Even better, you can create a DIY barrier wall that has specific gaps for horizontal and vertical surfaces that fit your installation.

Paint the Timber

Another great way of preventing your landscape timber from rotting is to paint it. Whether you use actual paint is up to you. You can also use protecting spray, waxes, varnishes, or quality oils to essentially waterproof your timber.

Paint in particular helps to keep moisture and fungus from attacking your landscape timber. Applying a new coat once in a while not only ensures that the timber retains an even look but also consistently fights moisture.

Fight Rot by Finding the Key Cause

Perhaps you have noticed rot after it is too late. Instead of chalking it up as a loss, try to find the route of the rot instead. Finding the key to the rot can at least help you prevent it from happening again should you install new landscape lumber.

Inspect your property. If you have a retaining barrier, inspect those as well. Look for any holes or cracks that might be allowing in moisture. Check for roof leaks as well. Roof leaks can allow water to drain into unwanted areas, which then leads to increased rot conditions.

Any painted surfaces that are either damaged or cracked should be checked out as well. When there are spaces for moisture and fungi to permeate, it can lead to an attack on the lumber. That eventually leads to rotting. Make sure that you tip your landscapers if you are happy with their work.

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Building a Garden with Railway Sleepers

The most common use of the aforementioned barrier would be in the case of a garden. Using timber to construct the walls can be a great way to keep your garden contained. The problem is that moisture in those walls can rot them, degrading the garden in the process.

You can build a garden wall with railway sleepers to combat that moisture. But how do you construct a garden wall with railway sleepers? Here is how to do it.

Step 1: Mark it Out

There is a simple fact that you need to realize. If you do not measure and mark out the size of your garden bed, then you can’t properly build a wall with sleepers. Pick an area that doesn’t require a lot of sleepers since they are a little tough to properly cut into the right size.

Make sure that you clear out any of the vegetation within the area that could slow you up. Not only that, the vegetation could potentially impact your installation. Take the time to clear out the area, plan out your setup, and get the proper measurements.

Step 2: Lay the First Sleepers

When you have all of your measurements, it is time to lay down the first row of sleepers. Lay them on the garden bed, making sure to leave slight gaps that allow for the easy flow of excess water. When excess water gets trapped, it can fester, eventually leading to rot and even harming the plants within your garden.

Make sure to take your time so that you properly lay out the sleepers. In addition to allowing excess moisture, misaligning the sleepers can just look bad. That drags down the overall aesthetic of your garden bed.

Step 3: Laying the Second Row of Sleepers

Double-check your first row installation. When you are satisfied with the installation, you can move on to the second row. While laying that second row, be certain that they do not overlap the joints in your bottom row of sleepers.

When they overlap, it can create a weak point in your retaining wall. When moisture builds up at the weak point, it can accelerate the rate of rot. Double-check your work and ensure that there is no overlapping.

Step 4: Finish the Wall

Repeat the previous steps, laying out your sleepers until you get the wall height that you want. You will need to drive nails through your sleepers to ensure that the wall is both sturdy and firm. Fill in any of the spaces in your retaining wall with soil or compost.

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The Verdict

When it comes to your landscape lumber, the key is prevention. Whether that is through some waterproofing method, such as painting the timber, or by building a retaining barrier with sleeper rails, is entirely up to you.

But a little bit of prevention and attention to the various aspects of the landscape can go a long way. Rot is the last thing that you want to deal with as it can comprise the integrity of your structure. That means repairs or replacement sooner rather than later.

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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