Garden wall advice.

Poe

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Hi all,
I'm going to be building a large boundary garden wall (rear garden) that will in a small area will be partly retaining.
I have dug the foundations down to 1 meter (at it's shallowest) to firm clay and 50cm wide and planning to have the concrete 30cm thick.
The wall itself I am looking at a finished hight of 2 meters or just below and constructed from a double skin of breeze blocks although my partner wishes it to be a single skin of blocks and a face of red bricks.
I am very confident of my brick laying abilities but just wanted some feed back on the project as it progresses.
So really my first question is are the planned foundations of a suitable size and strength to support the wall.
The retaining section of the wall is only going to have around 45cm of soil hight in one corner for approx 3m in length both sides of the corner.
Cheers Poe.
 
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Foundations seem deep enough. 600 would be better than 500 wide, but that may be near enough.

Depending on the length, you may need expansion joints above ground level.
 
Thanks woody,
I may widen the foundation but I am also thinking of putting extra piers in which would widen it at those points and as strength to the wall.
I'll do a sketch of the lay out to make it easier to understand the wall itself and post it up here tomorrow.
I was planning on putting at least one expansion joint in each length but more likely will use two.
I'm guessing there isn't any need for rebar in to the foundation.
Cheers Poe.
 
2m sounds quite slender even at double skin, not sure if you’d need piers or something? Not that I’m basing that on anything, just trying to picture it

ignore me, just seen your comment about piers
 
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When I built my "tall wall", I read, if I recall correctly, that the height of a freestanding wall is measured from where it is built off the concrete and not where it comes out of the ground - so in effect if you build a 2m high wall with 700mm below ground you have a 2.7m high wall - better to fill your trench to just below ground level.
 
Better to build block flat rather than 2 skins with ties between.

1300 × 956
Not like that it isn't - that's the numpty way. That gives a very slender height to length ratio which makes each block more prone to cracking.
If blocks are to be laid flat, then they should be laid one on top of the other for two courses, and then bonded and so on.

But even so there is no advantage in laying blocks flat - its harder, takes more time and uses more mortar.
 
A free-standing boundary wall 200-215 thick is too slender in the absence of substantial piers.
 
Not like that it isn't - that's the numpty way. That gives a very slender height to length ratio which makes each block more prone to cracking.
If blocks are to be laid flat, then they should be laid one on top of the other for two courses, and then bonded and so on.

But even so there is no advantage in laying blocks flat - its harder, takes more time and uses more mortar.

A wall built with blocks laid flat is around 50% less efficient in vertical load-bearing capacity.
However, in a garden wall, vertical load-bearing capacity is not an issue, but horizontal wind load is. In this case, two 100 thick skins tied with wall ties is less efficient than blocks laid flat.
 
A wall built with blocks laid flat is around 50% less efficient in vertical load-bearing capacity.
However, in a garden wall, vertical load-bearing capacity is not an issue, but horizontal wind load is. In this case, two 100 thick skins tied with wall ties is less efficient than blocks laid flat.
And what about disproportionate or seasonal foundation movement, professor?

A 2m 225mm wall will take wind load no problem so the "efficiency" argument is immaterial. It's vertical movement that is the risk, not horizontal.
 
Sorry, Woods, but the main force to be considered in the design of free-standing walls is wind load.
Also, blocks laid flat in the context of free-standing walls are more efficient than those laid vertically.
 

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I think maybe I was miss understood when I said I would put extra piers in.
By this comment I meant that I was already going to be using piers to strengthen the wall. However, I was considering putting extra piers to add extra stability and strength.
At no point was the wall going to be constructed with no piers.
I was also of the impression blocks laid flat would overall be weaker.
CDBE are you speaking in turn off rotation of the foundation or in terms of building control and reg in regards to wall hight.
Cheers Poe.
 
I've done a very basis sketch which hopefully it's clear to view the red line from points B to C to D are where the wall will be build there is a gentle slope in the garden towards point C and it is this area which will be retaining up to approx 45cm although I will be leveling from point A and hopefully the soil level at point C should be lower than stated.
I've not put any indication of pier or expansion gap location as I will take further advice from everyone and see what will produce the best layout from that advice.
With regard to wall construction and without going into over kill what are you guys thinking if a double skinned block wall with piers is to "slender"?
I would there be benefit of building a cavity back filled with concrete.
Cheers Poe
 

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When I built my "tall wall", I read, if I recall correctly, that the height of a freestanding wall is measured from where it is built off the concrete and not where it comes out of the ground - so in effect if you build a 2m high wall with 700mm below ground you have a 2.7m high wall - better to fill your trench to just below ground level.

The effective haight of the wall is the height from the top of the footing.
 
From an engineering point of view or building regs point of view?
If the latter I would guess there would be a lot of people with exposed foundations above ground and very tall walls.
Poe.
 

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