Advice building small wall in garden for raised border

[nightowlkb]

Hi folks,

I am going to build a small wall in my back garden for a raised border, but I haven't done any brick laying before. I have done a bit of pointing, so I'm not completely hopeless lol. My main question is how wide and how deep should dig for the foundation. I'm intending to dig a ditch and fill with a dryish mix of concrete, and then flatten it off with a big spirit level. I saw online somewhere that 75mm is a good enough depth + extra for sitting half the first course of bricks below the soil level. What I am going to build is a single skin wall 5 courses high. If you look at the attached picture I have arranged them how the wall is going to be. What do you guys reckon for the foundation? Do you think the wall is low enough to be single skin? It's not going to be massively under strain as it's only a small ish border but I do want it to be reasonably strong. Also for cutting the 2 bricks I need for the back would I be better using a grinder or a bolster chisel and lump hammer? Thanks in advance.

Kieran

 

[Doghouse Riley]

Hi and welcome.

What you're suggesting seems fine.

Personally, I'd make the border a bit wider, think long term, you may want to add more plants later.
When laying your bricks you need a long level or a straight edge that will cover three bricks with the level on top.

It looks as if your "dummy run" is falling away to the right end. But with your level across three bricks each time you lay one it'll be fine.

 

[nightowlkb]

Thanks for the reply @Doghouse Riley , I appreciate you taking the time! Sound advice regarding the level over 3 bricks, il be sure to do that!

 

[MarineBob]

My five cents worth. I would not make the bed too deep. I have raised bed veggie garden beds and I made them too wide. think about being able to reach into the farthest point you want to get to. Were I to redo the beds, I would have made them narrower. Anyway, for what its worth. Also, think about putting in some drip irrigation pipes. I used some stuff from the Orange store that's easy to work with. Not fancy and I simply hook up my hose to the end with a quick disconnect. Get some of the drip heads and you can adjsut what each plant needs. Work well and do not use much water.

 

[DaveW]

Key things to consider: 1) Your bricks need to be on firm ground that will disperse (spread) the load sufficiently to avoid subsidence of the wall. In terms of thickness of the foundation, the load of any given wall permeates at 45 degrees to the horizontal. So if your bricks are 100mm wide and your foundation 100mm thick (which I would recommend) then your strip foundation needs to be 300 mm wide (hope this makes sense), Anything thinner and you are defeating the object of having said foundation. 2) Do not create a water or ice trap. Make it wider, ensure that the ground beneath the foundation is 'sandy' enough to drain. 3) Make your wall flexible. Add a small amount of lime, if available, to your mix. This will avoid cracking of what would be brittle mortar in the future. .. Walls need to breath and move. Mix your mortar 1 part cement, 3 parts sand (to make it strong enough to avoid frost damage ...and 1 part lime if you have some to hand . garden walls are a great environment for bricklaying practice. Enjoy

 

[DaveW]

...if you trap water, it will freeze and your wall will be the first thing to be broken

 

[MarineBob]

...if you trap water, it will freeze and your wall will be the first thing to be broken

Good thought, might want to put a perforated pipe down near the bottom on the inside to drain away any wateer, along with some stone.

 

[piglet11]

And put a membrane in the bottom to stop unwelcome visitors.
Pays to use decent topsoil to fill it with. One tonne bag not too expensive.

 

[DaveW]

if you lived near me you could have more than a tonne for free. ...One of the downsides of building an extension is soil disposal ;-)

 

[piglet11]

DaveW
Build your very own hill?
I found that just de-clagging it and generally spreading it around soon gets rid of it.

 

[nightowlkb]

Hey guys thanks for all of the replies! I wish I would have logged on to this sooner, it notified me about the replies up to marine Bob, but for some reason I did not get any notifications of replies after that so have only just seen these comments. I have built my wall now, and I think it looks pretty good for my first go! Il attach a pic so you can see for yourselves lol. The spirit level over 3 bricks helped me a lot @Doghouse Riley thanks for that one! I did my foundation 3 times as wide as the bricks them selves @DaveW and a spade deep so hopefully that's enough! I made my mortar mix 5 sand to 1 cement though, as that is what the cement bag I bought from wickes said on it. I put a bit of washing up liquid in it too. Do you think that's going to be enough? Suppose it's a bit late now for that question lol. @MarineBob what diameter of pipe should I use for the drainage? I haven't put one in but could drill a hole to make room if it will help stop frost from undoing my work!