Building A Garden Retaining Wall- Doule Or Single Reeze Block

[madonna-fan]

I am just starting to build a retaining wall for the end of my garden (about 6ft), laying the breeze blocks flat,single row ,but my now-all next door neighbour has told me that his wall is vurtually Earthquake proof bcause he has put 2 rows and not 1 which i wa advised to do.Is this overkill on his part or is his way the correct way - ANY ADVICE IS MUCH APPRCIATED.

[SlackAlice]

Do you live in an earthquake prone zone, if not, then it's just overkill. Bragging rights probably.
Your saying 'retaining' wall, what are you retaining?

[Zacs-Master]

A garden.. It says in the question.

[SlackAlice]

soil, rubble, sand etc

[buildersmate]

You failed to tell us the height of this retaining wall, which is the critical factor.
I assume 6feet is the length, not the height.

As a GENERAL rule, for a low height retaining wall (up to one metre high) the width should be between one half and one quarter of the height - so between 250mm and 500mm width, depending on the characteristics of the subsoil and the height of the water table (because of hydrostatic pressure).

Any higher than that and you need to employ the services of a structural engineer to calculate the design.

[madonna-fan]

thanks everyone. 6ft is actually the height of the wall.My garden slopes off downwards and a lot of the length is wasted spaced because it is unusable becaause of the angle of the slope. this is why i want build a retaining wall and build up my garden and get the full length out of it- many thanks again

[buildersmate]

If it is six feet high, I would not attempt this without the input of a structural engineer to design it.
There is some information that corroberates what I am saying (scroll way down to retaining walls).
http://www.pavingexpert.com/featur03.htm
There are various ways to do this, including sloping the wall backwards into the bank, putting structural steel into the thing.
I cannot stress enough that you need help to design this - including what backfilling you put behind the wall to allow water to flow down, and what exit arrangement you make for the water to the front wall low down.
The sideways pressure exerted is measured in several tonnes at this height.

[The Builder]

Sorry to be killjoys Madge, but BM is absolutely right. An engineered wall is really quite simple. You could still do it yourself, but it's very different from a standard block wall.

Alternatively, if you have enough length in the garden, you could pile the material to the height you want and then slope it off at around 45 degrees, as with an embankment.

[modeller]

6ft high straight walls can be built with single bricks as long as they are buttressed at both ends and at intervals along its length. The intervals depends on the situation . In your case it would require one at each end and two in between making a total of four. That would actually be stronger than your neighbours.

[Canary42]

An upright retaining wall is a significant project - when I was a young lad our neighbour erected one such, including buttresses, but one day the whole length of it just fell down (luckily nobody near it at the time). He then rebuilt it at a slope.

[buildersmate]

Not when there's tonnes and tonnes of soil behind it, modeller.

[modeller]

I didn't get the impression there were tons of soil behind it especially as he had been advised to use 1 row .