How to build a garden wall: advice for timber, brick, and retaining styles, plus more

Want to learn how to build a garden wall for your backyard? It's a great weekend project, will save you some money rather than paying for a pro, and isn't that difficult.

Garden walls are key features in a plot for all kinds of reasons. They can provide shelter and privacy, divide your space into distinct zones, or, in the case of retaining wall ideas, hold back soil to create different tiers. And there are lots of styles to go for, depending on your budget, how sturdy the wall needs to be, and your preferred aesthetic.

We've brought together some straightforward guides on how to build a garden wall using different types of materials to help you complete your DIY project successfully.

How to build a garden wall from bricks

Perhaps the most go-to approach for building a garden wall is using bricks. It's sturdy, economical, and if you've got a bit of DIY experience already, not too tricky to do. 

To learn how to build a simple wall in this style, follow these step-by-step tips from Homebase below.

You will need:

• A tape measure, available at Amazon
• Thin pieces of timber
• Pencil
• Club hammer
• Bolster chisel – again, try Amazon
• Mortar, plus something to mix it in and a spade (our guide to the best garden spade has lots of great picks if you need a new one)
• String and line pins
• Spirit level
• Brick trowel
• Brick jointer
• Gloves to protect your hands while you work
• Safety goggles

Method:

1. Lay a solid foundation for your bricks, and then decide how many courses (horizontal rows) of bricks you want. Using a pencil, measure out each course on a piece of timber – you can then use this as a guide to make sure your wall is straight as you build it.
2. Lay another narrow piece of timber along the edge of your foundation, where you wish to build the wall. This will also help as a guide for keeping it straight.
3. Lay a bed of mortar on top of the foundation, then lay your first brick at one end.
4. Add a small amount of mortar to the end of the second brick, then push this into place, next to the first, using the timber as a guide to keep it straight.
5. Continue laying the first row of bricks, then use a spirit level to ensure it is all level.
6. When building a wall, you need to lay the bricks so that the center of each is above the joints below. This means that some of your end bricks will need cutting to the right size. To do this, use a bolster chisel and a club hammer on a firm surface. Score where you want to cut it first, using the chisel and another brick. Then, with your safety glasses on, align the chisel across where you've scored and strike it with the club hammer to break the brick in half.
7. Lay mortar on top of the first three bricks at one end of the first course. Use your trowel to feather through it. Then, start laying the first few bricks of your second course, ensuring the end brick is square and level to the brick below by using a spirit level. Use your guide that you made earlier to check that it is at the right height, tapping the brick down if needed using your trowel. Repeat this at the opposite end, so that you have bricks on both ends of the second course, but a gap in the middle. 
8. Create a level line by using a length of string with pins attached to each end. Insert one pin at one end of the wall, into the mortar below the first course of bricks. Extend the line up and over the bricks, along the length of the wall, and down over the bricks at the opposite end. Insert the other pin into the mortar at this end, ensuring that the line is pulled reasonably taut. You can tension the string at each side by using a small amount of mortar and a brick laid on its side.
9. Apply a bed of mortar across the first course of bricks, between the two ends. Adding a small, feathered amount of mortar to each brick, lay each one next to one another to complete the course. 
10. Repeat the steps above to continue building your wall. Remember to keep checking it with your spirit level as you build to make sure it's straight.
11. Once your wall is at the height you want it to be, fill in any gaps in the mortar using a brick jointer by smoothing the mixture over.

How to build a garden wall from timber

Garden walls can also be built from timber, including garden sleepers. Just ensure that the timber you use is weatherproofed to stand up to the elements.

Using timber is a popular approach for retaining walls as it gives a natural yet smart look that will complement your decking ideas and nearby planting well. 

Leigh Barnes of Jacksons Fencing shares his tips on how to build a retaining wall from timber:

1. The area for the wall and the space in front of it need to be dug out. Dig a trench below the new ground level to form the base of the wall – this should be approximately three layers of timber deep.
2. Drainage is integral for a strong retaining wall, so lay gravel at the base of the trench. Laying a porous membrane (such as weed suppressant) on the bank behind the wall will prevent earth from sliding into the channel.
3. You can then begin to layer the timber sleepers using a 'bricklaying' technique, ensuring at the corners that the ends overlap.
4. Secure the structure using screws. For taller walls, you may require vertical timbers to support the wall.
5. Leigh recommends installing a perforated drainage pipe along the line of the wall with one end clear to drain away. This will prevent water build-up behind the wall. He also suggests backfilling behind the wall with coarse gravel as you build, ensuring the porous membrane stays in place, to prevent blocking the drainage. 

Of course, your wall doesn't have to be a retaining one. A simple timber wall makes a great garden divider between zones. 

Mark it out first using string lines and pegs – this will help you keep it straight. When it comes to the build, ensure you construct it on a sturdy foundation. Some people choose to add a layer of concrete over a smoothed layer of fine gravel in their trench, then use coach screws on the bottom row of sleepers to secure them to the mixture as it sets.

Then, it's simply a case of stacking the timber, overlapping where they join, and using screws to secure each piece to the piece below. Regularly use a spirit level as you build to keep checking that it's straight. If you're building a tall wall, you may need to add a series of vertical posts for added support.

You can also use timber sleepers vertically to create a wall. Cut them to the desired size, and line them up side-by-side in your trench filled with fine gravel. Then, when you're happy with their positioning, add in a dry cement mix and water to set them in place.

Sleepers can be used in other ways, too – our feature on garden sleeper ideas has plenty of inspiration.

How to build a retaining garden wall with concrete blocks

Building a wall with concrete blocks is generally the cheapest approach. Thomas Goodman, a construction expert at MyJobQuote.co.uk, shares his step-by-step guide on how to build a retaining design using this material.

1. You can start digging the trench after you've marked out the arrangement. Dig a hole 4 to 6 inches deep and 12 inches broad, or twice the width of the block, to bury the first course or first row about halfway.
2. You'll have to step up or down to keep the blocks level if the trench slopes. Create stairs with a torpedo level to ensure it is built correctly. If you don't want the wall to run parallel to the slope, use a hand tamper to compact the soil and maintain its level.
3. Fill the trench with about 3 inches of paver base and tamp it down with a rake. The foundation is strengthened by tamping the base. When everything is level, you can start putting the block in place. Then, starting at the end of the trench at the lowest elevation, knock out the flanges with a hammer and chisel so each block will lie flat, then set the first block in place and check for level.
4. Place the next block on top of the first, making sure it's level. Continue putting in the first row, checking for level regularly. Fill in under a low block with a paver foundation or tap down a high block with a rubber mallet to level and keep the rows even.
5. Then get ready for the second row by sweeping the dirt off the tops after each row is installed. You'll need to cut a block to stagger the joints for the second row. It should be marked and cut with a masonry blade.
6. Place the cut block in place, ensuring the flange is flush with the first row. Make sure it's level. You'll need to put drainage directly behind the block after installing the following few rows. Install landscape fabric behind the wall, leaving enough to reach the block's top.
7. As you construct the wall, fill in the area directly behind it with gravel. Apply concrete glue to the wall block tops for the last two rows of a full block, then set the next row of blocks in place.

The process is more or less the same if you're creating a non-retaining wall, too. Just remember to build on a sturdy foundation, and they'll be no need to add landscaping fabric or gravel to one side as you build.

How to build a dry stone wall

Dry stone walls are a very traditional approach dating back hundreds of years. These walls don't use mortar, but they're still very sturdy and long-lasting. 

They can be spotted all over the English countryside to mark field boundaries, but also make an attractive feature in a backyard. Because of all the nooks and crannies, they can be filled with plants and they're great for wildlife garden ideas.

1. Prepare the site by marking out where you want your wall to be and digging a trench for the foundations.
2. Use the largest stones you have at the bottom of the trench and fill in any gaps with smaller ones.
3. Begin to layer up the stones, arranging them so that each lies as flat and horizontally as possible. The Wildlife Trusts recommends tapering the wall as it goes up, which will increase its stability. So, work in an A-shape, filling the middle with smaller stones. 
4. Larger walls benefit from the addition of large 'through stones' at regular intervals which span the entire width of the wall.
5. Add a row of coping stones at the top of your wall. These should stand upright, be pushed closely together and have good contact with the wall beneath, and span the width of the wall. 

How much does building a garden wall cost?

According to HomeAdvisor.com, the cost of materials for a concrete block wall is generally between $3 and $5.50 per square foot (the equivalent of £2.25–£4.15), including mortar and structural reinforcement. This is generally the cheapest option if you're looking for budget garden ideas. 

Timber for a wall can be around $15–$30 per square foot (that's £11.30–£22.65). Traditional bricks cost around $35 per square foot (£26.40), plus the price of the mortar and concrete, while natural stone costs $25–$80 per square foot (£18.85–£60.35) plus mortar and concrete if using.

Of course, one of the benefits of learning how to build a garden wall yourself means you won't have to pay the labor costs of hiring a professional. Looking for more info on how much landscaping costs? Our guide explains all.

Do you need planning permission to build a garden wall?

In the UK at least, you generally don't need planning permission for a garden wall as long as it complies with a few important factors. These include it not being over two meters in height from ground level (unless it is next to a highway used by vehicles, or the footpath of such a highway, in which case it should not exceed one meter in height). You'll also need to ensure you're not on a listed site. 

Wherever you are in the world though, it's always worth checking with your local authority before beginning a project. In the UK, the Planning Portal is a useful resource.

Looking for more DIY projects to transform your backyard? Our guides on how to lay a patio and how to build a garden pond might be for you.