DIY Doctor UK DIY Forums

Hi All

I am planning to build a retaining wall 1900mm high, by the advice of this site (https://www.diydoctor.org.uk/projects/retainingwall.htm) and the hight being 4 times the thickness that would mean it needs to be 475mm thick which is huge.

However it says that reinforcing the wall doubles it strength. Does that really mean i can halve the width to 237mm. If this is the case I was thinking of 2 block skins 100mm wide with a 50mm gap with reinforced steel and filled with concrete.

Am I correct and this will be OK?

I am sure that my math is OK but what I want to check is that by reinforcing the wall I can actually half the width of it. It seems too easy an answer.

If I am, the foundations need to be twice the width of the wall so 500mm?

Im afraid the diy doctor is right,if your building a wall that high and the subtance behind it is to the height of the wall you will need it to be 450mm thick minimum plus you will need drainage in the wall.
I would seek proffesional help before starting.

[quote="welsh brickie"]Im afraid the diy doctor is right,if your building a wall that high and the subtance behind it is to the height of the wall you will need it to be 450mm thick minimum plus you will need drainage in the wall.
I would seek proffesional help before starting.[/quote]

Hi thanks for your reply, what I am really unsure of is does reinforcing the wall mean i can half the width as it says it doubles the strength.


Burger

Hi Burger, how's your wall going?

I built a retaining wall of similar height 3 years ago. It was just under 2 metres high, 1.95m
I took professional advice and the wall construction went like this :

first 5 courses were blocks placed lenghtwise so the wall's width was 440mm to start.
Next 5 courses were blocks placed flat so wall width was 220mm.
Finally the last 2 courses were blocks upright so wall's width was 150mm.
We used 150mm thick blocks not the standard 100mm thick ones.

The back of the wall was stepped with the front face flat. Drainage by way of perforated pipe was used going into a soak away.

I was retaining my neighbours garden.

6 months ago my neighbour got planning permission to build an extension and has now excavated his garden down to the same level as mine for the full length of my wall!!! Bloody typical if only i had know.

Anyhow the wall is now demolished and there are wooden panels in its place. Hell of a job to demolish the wall mind.

Marcus