Retaining Wall Advice Required

[indy4x]

Some of you may have seen random posts over the last 3 years on my lockup project.

Recently I had the footings dug ready to get the foundations in for a retaining wall around the perimeter to the rear of the lockup si I can level off the ground and fence it off.

The retaining wall will be U shaped with the left hand side being 12m long, the rear 11m and the return leg on the right hand side 4m

The number of courses will vary as the ground is sloping (footings have steps in them) but essentially the 12m section on the left will taper from 2 courses at the start to 5 courses where the return is to run along the rear. Most of the rear will be 5 courses with the last 2m being 4 courses as will the return leg on the right hand side

I am planning on using hollow blocks for the retaining wall rather than normal dense blocks on their side. The holes in the hollow blocks will be filled with concrete and will also use them for the fence posts

Does this make sense are there any disadvantages of with my plans or am I better off going block on their side instead?

I saw some pictures on the interweb that had rebar sticking up out of the foundations that came up through the hollow blocks, is this necessary? I could put rebar down the holes when they are concreted in if this helps

For the avoidance of doubt, this is what I'm referring to as a hollow block



The retaining wall will continue from where my poor efforts finish alongside the lockup, I will be farming out the blockwork to someone that can actually do a tidy job



The fence posts in the left of this photo are where the rear section of the retaining wall will be, the nice looking garage is my neighbours and the right hand return will finish against his garage as thats on the boundary. It will be probably 12" below his damp course



Thanks

 

[gaz1]

a 6" hollow block isnt enough ive seen it move as not wide enough with retaining walls

your better off either using proper concrete or blocks on there sides

if you go with hollow block your going to want rebar and a good concrete rebar base

 

[Agroshield]

a 6" hollow block isnt enough

I have searched and searched and for the life of me cannot see a number 6 anywhere in the post above yours.

Perhaps you could comment on the proportions of the picture he shows. If any one of the dimensions in it was 6", what would that make the other dimensions?

Thirdly, he says "the holes in the hollow blocks will be filled with concrete and will also use them for the fence posts". Could you point out a fence post that would fit inside a 6" block.

Thanks and have a nice day.

 

[sako243]

I've been going through the same thought process and (admittedly pre COVID) went through some numbers and it was more cost effective, assuming you were paying a bricky, to do a shuttered concrete wall. This was for a retaining wall on 3 sides for a ~7.5x7.5x4m garage.

That included rebar in the slab and walls all tied together. There are companies up your way (furthest west was Swansea I think) who you send them the design of the wall and they'll deliver a set of panels and bracing for shuttering the walls. You can then assemble yourself or get someone to do it and then pour the concrete and once gone off dismantle and return the shuttering.

In my scenario there's a lot of ground water and speaking to the chap who poured the concrete slab for the workshop he said don't bother with waterproof mixes but just whack a DPM down around and up the walls. Generally speaking 300mm of concrete is considered "waterproof" so with a DPM and some French drains around it that would be more than sufficient for handling the water.

 

[weldingnovice]

Not really sure what material you plan on retaining, but if you're going to be putting fence posts into those blocks would definitely tie into the footing with rebar.
Not much tensile strength with mortar and going from your description not a lot of mass to hold down a fence if it gets too windy.

 

[6ply]

I had to get a retaining wall dug around my garage (the garage itself as acting as a retaining wall with consequent issues for drainage and other storage problems). I received a lot of "advice" from online brickie forums stating it would be impossible for an amateur to do the job myself but I went ahead anyway. Dug it out by hand (about 48 tonnes) and did the foundations and blockwork myself. I used solid high density concrete blocks with a good width of foundation, sufficient piers / stagged blockwork (see attachment), re-enforcement, movement joints, etc. Still looks good and has not fallen down.

Before beginning the work I contacted a structural engineer for advice. His fee was **way** too high but he was kind enough to spend a few minutes on the phone for free and email me the GBG document which you may find useful. Good luck.

 

[6ply]

I'm not sure whether it would be suitable for your application, but when I was considering how best to build a retaining wall I came across mortar-less designs using interlocking blocks. If you are not familiar with the systems, here is an example.

Secura Lite Concrete Retaining Wall System For Landscaping Projects

Secura Lite is a architectural retaining wall blocks system for commercial wall projects designed to combat sloping site issues make efficient use of space.

www.tobermore.co.uk

 

[gaz1]

this will help

it all depends on what your going to do on top or what weight your going to have on the ground above

its also important on the height of the retaining wall it looks to be about 4-5ft high

 

[Bravheart]

Not a retaining wall as such but those hollow blocks seem to be the go to lego brick around farm yards. We have one filled with concrete and steel bars, gets pushed against most days scooping bulk material up with a forklift. Been up 20+ years and so far so......

 

[500e]

We shutter and pour that sort of thing for commercial
Or 9"blocks flat for just a wall 2 Mtrs hgh 30 years old.
Doing a bit at home to paths etc at present

 

[indy4x]

Thanks for all the replies, much appreciated

Wall will be max 5 courses of block, of which 4 courses will be above ground so probably 900mm high

The ground behind the lockup slopes down to the boundary so it is there for me to level off the ground and erect a fence around the boundary

I will be placing a lorry body on the ground for storage, erecting a car port type affair between the lorry body and rear of the lockup.

The rest will be an open space, somewhere to park the camper and whatever other rubbish I acquire