Engineering bricks?

[Launchbury]

Untitled

• Launchbury
• 10 Apr 2011
• 1

Do I have the engineering bricks in the right place for a retaining wall?

If it was a free standing garden wall should the engineering bricks be the first 2 courses above the ground level?

Any help much appreciated.

Many thanks in advance.

 

[noseall]

Yes, you would normally show two courses up to 150mm above g.l.

You may be better off backing the planter with 7n dense concrete blocks then finish off any visible masonry with facing bricks and coping.

If you are not fitting a drip to the coping i.e. a tile crease then i would strongly recommend using a rated brick for the entire planter facing.

Use 65mm square rainwater downpipe for the weepholes as this size sits nicely between metric brick courses. Anything smaller will clog up and be useless. It is debatable whether they will be needed at all.

 

[Launchbury]

Thanks Noseall for the excellent reply, 2 questions;

1/. Does that mean I should have 2 courses of engineering bricks below ground level and also the next 2 above ground level?

2/. You say use a rated brick the entire planter facing, what do you mean?

Thanks again.

 

[noseall]

1/. Does that mean I should have 2 courses of engineering bricks below ground level and also the next 2 above ground level?

Affirmative.

2/. You say use a rated brick the entire planter facing, what do you mean?

Softer bricks do not fare well in exposed garden walls. So, if you have no drip on the coping then i would advise using a harder brick throughout the whole face of the planter. This is not to say you have to use an engineering brick throughout but one that is FL rated.

 

[^woody^]

I can't see any point in having engineering bricks just for below ground level or the 2 courses above - unless its purely for decorative purposes

All the bricks in this wall are exposed and in contact with soil, and so just using engineers at the bottom serves no purpose

In addition to nose's good advice, I'd add that it will be a good idea to consider draping some thick polythene down the back of the wall or coat it with a waterproof barrier, as otherwise damp will leach through the wall and at the minimum cause horrible salt and algae staining, or worse still, blow pointing and spall the brick faces in a few years

 

[wavetrain]

The wall as drawn would also start to lean before too long. The book - Building and Construction handbook, has details on building retaining walls that would suit your requirements

 

[^woody^]

The wall as drawn would also start to lean before too long.

I don't think so.

How did you work that one out?

 

[wavetrain]

The wall as drawn would also start to lean before too long.

I don't think so.

How did you work that one out?

From observations of similar retaining walls that have leaned. Perhaps Woody only expects builds to last a few years?

Now, Chudley does say you can build a small retaining wall in height 2 - 4 times its width, and as drawn this one is less than 4, but I would beef it up and reading Chudley will do the OP a world of good.

Woody perhaps you should read Chudley too?

 

[^woody^]

You don't even know what ground that wall is retaining, whether it is stable or liable to move, or what pressures may be placed on that wall. So you can't make a general statement of it leaning in a few years

The most important part of that wall is the foundation, and the most thrust is going to be on the bottom third, and the rest of the wall is doing very little

The OP's wall at a mere 700mm high and one brick thick and on the type of foundation shown, is not going to be leaning over any time soon - whatever is behind it

 

[Launchbury]

Thanks for replies - all useful.

Fyi; the retaining wall is for a raised planter, holding topsoil so I'm not concerned about it moving.

I have just ordered the Chudley book off Amazon.

Thanks again.

 

[freddiemercurystwin]

Rough rule of thumb for mass retaining wall is that the depth at the base should be about 1/4 - 1/3 of the height, what's been drawn will be fine.