2-3 metre gardens wall - HOW DEEP foundations have to be dug?? for a 2-3 metre wall?

System

It depends on the load bearing capacity of brown soil :money:

plumface

Danny_G wrote: »

thanks for the thickness advice, and pipes advice.

But what about the depth of the wall foundations, for a
2 metre wall,

and foundation depth for a 3 metre wall?

- it is a garden wall, with soil foundatrions, and mabey solid garden brown soil deeper

Have you not read any of the previous replies?

mysk_girl

It impossible to say without seeing the soil first hand. The last freestanding wall I did that was that high had footings about 2m wide and over 1m deep due to poor soil. You need to consider windloading on the wall for overturning, vertical load bearing capacity and frictional resistance to sliding. 3m is a massive wall! The windloading will depend where in the country you live, I live and work in a region with comparatively low wind speeds, but a 10% increase in wind speed can result in 21% more force on the wall, as force is proportional to speed squared. 20% faster winds = 44% increase in force.

There is guidance from the NHBC regarding the construction of garden walls that gives guidelines, but these are only valid up to 600mm height.

And, as someone mentioned above, you will need planning permission to erect a 3m wall. Off the top of my head, the limits below where no PP is required are 6' for rear gardens (1.8m) and 4' (1.2m) if the wall adjoins the highway.

gmgmgm

3m is a pretty big wall. It's not going to be a retaining wall is it?

(If so- you'll need to significantly beef it up).

27col

Just what the hell is a soil foundation. There is no such thing. You certainly do not build on topsoil, at the very least you would dig down into the subsoil.When I built my front wall the foundations were at least18" or perhaps 2ft deep. It has stood for nearly 40years. Most damage has been caused by the faces of the bricks spalling. No amount of foundation would have stopped that happening. But there are some cracks due to the adjacent A27 traffic.Whether these would have appeared if the foundation had been deeper is difficult to know.

planning_officer

mysk_girl wrote: »

And, as someone mentioned above, you will need planning permission to erect a 3m wall. Off the top of my head, the limits below where no PP is required are 6' for rear gardens (1.8m) and 4' (1.2m) if the wall adjoins the highway.

Almost! It's all metric now... so it's exactly 2 metres in height if a wall is not adjacent to a highway, and 1 metre in height if it is adjacent to a highway (which includes pavements, verges etc). The only exception is if you are replacing an existing wall that is higher than 2 metres - you can erect a new wall up to the same height without requiring a planning application.

In some sensitive locations, permitted development rights may have been removed by the local Council, so in those areas any wall can require planning permission. Also, if the wall is around a listed building, then it will always require express planning permission, whatever height it is.

Danny_G

27col wrote: »

Just what the hell is a soil foundation. There is no such thing. You certainly do not build on topsoil, at the very least you would dig down into the subsoil.When I built my front wall the foundations were at least18" or perhaps 2ft deep. It has stood for nearly 40years. Most damage has been caused by the faces of the bricks spalling. No amount of foundation would have stopped that happening. But there are some cracks due to the adjacent A27 traffic.Whether these would have appeared if the foundation had been deeper is difficult to know.

I didn't mean a soil foundation, I mean soil dug, deep to pour concrete in there, to make it a concrete foundation.

and I am asking:
when the wall is 2 metres high, how many metres does the foundation of concrete need to be? (how many metres DEEP do we need to dig down into the ground to fill with concrete to make the foundation)

when the wall is 3 metres high, how many metres does the foundation of concrete need to be? (how many metres DEEP do we need to dig down into the ground to fill with concrete to make the foundation)

How many metres high was the wall that you built and lasted 40 year?


NOTE- the wall IS NOT near any roads, or public places

mysk_girl

It's not just how deep, it's how wide as well. And the answer is, again, it is not possible to say without knowing the type of soil. "Brown" soil could be anything.

Chopper_Read

Danny_G wrote: »

I didn't mean a soil foundation, I mean soil dug, deep to pour concrete in there, to make it a concrete foundation.

and I am asking:
when the wall is 2 metres high, how many metres does the foundation of concrete need to be? (how many metres DEEP do we need to dig down into the ground to fill with concrete to make the foundation)

when the wall is 3 metres high, how many metres does the foundation of concrete need to be? (how many metres DEEP do we need to dig down into the ground to fill with concrete to make the foundation)

How many metres high was the wall that you built and lasted 40 year?


NOTE- the wall IS NOT near any roads, or public places

The general rule for brown soil is 100mm down for every metre high. Or double if it's by a road or public place.