Building Retaining Walls…

There seem to be a few construction/DIY/gardening types on here so I thought I’d ask a quick question.

I have a steeply sloping wooded garden that I want to terrace with retaining walls to make paths and more usable space.

The walls will be up to 5 feet high and I plan to use a concrete block construction faced with stone something like this…

I can’t find much info online apart from using prefab block systems, so does anyone have any advice? My main concern is if I need to include any sort of buttressing or piers in the wall, or what I can do to the back of the wall to strengthen it and prevent it shifting over time.

Thanks!

My guess is concrete blocks then use tie ins and build the nice wall just infront.

There are a couple of options, either an upside down wedge so the base is much thicker than the top, or a big L shape so the soil is above the bottom of the L avoiding any rotational forces.
A lot depends on the severity of the slope, but if walls are 5′ high then must be quite a slope!

Gabions??

http://www.gabion1.co.uk/gabion_retaining_walls.htm?gclid=CIno96iciL8CFXPKtAodBjAAjg

http://www.esi.info/detail.cfm/Maccaferri/Timber-Crib-mass-gravity-retaining-wall/_/R-23526_OX42JZ

Not what you asked but timber crib walls are good and easy to build.

What ground are we talking? Rocky, no big worries. Porous sandy/soil, worries as it will shift over time and load up on your wall.

The soil is heavy clay. It drains reasonably well due to the gradient and I’ll be putting lots of drainage in. This picture shows the type of terrain…

I basically want to create a flat area in the back corner (around the large sycamore tree), then another flat area where the path currently runs, so excavating back a bit to where the new retaining wall will be…

http://www.allanblock.co.uk/retaining-walls/getting-ready.aspx

I’ve seen the Allanblock website and it’s a pre-fab interlocking block system. I’m looking for info on building similar sorts of things using standard concrete block/stone.

Some good inspiration on there though…

To do properly. You would need something along the lines of 750 wide strip footing , two layers mesh, steel starter bars tied at 200 centres to the bottom layer of mesh. Backfill said trench with 250 mm of concrete. Place over bars 9x9x18 hollow blocks. Fill pockets with concrete. Backfill with choice of muck. Allow for drainage holes through the wall. This is a basic and simple design and depth/mesh/bar are all variable. Just building say a block flat wall has next to sod all stregnth as all the loading is basically on the bottom mortar joint.

next to sod all stregnth

Nice technical terms there 8) (but you’re correct, it would probably fall down)

there’s a fairly good design on this web-site
link
not that you can read the detail, but its fairly easy.

what i would do is just work on the following basics and do a basic design yourself

wall thickness at the base should be approx half the height of the wall – reducing in thickness as you build it up
ensure the concrete foundations are at least 150mm thick and are approx 150mm wider than your base wall (so for a wall 1m thick, ensure you foundation is 1.3m)
ensure you backfill with clean stone – to help water drain at the back of the wall
install weep homes every 1m or so
build it up in levels and ensure you tie the facing stone to the rear blocks.

i recently built a 6/7ft RT wall at home and faced it in random walling stone, i didnt point the face, i tried to make it look like a dry stone wall so i just cemented the backs and sides of the facing stones. looks good now!

In “the trade” I like to use such lamens terms 😆

random walling stone, i didnt point the face, i tried to make it look like a dry stone wall so i just cemented the backs and sides of the facing stones. looks good now!

That sounds like what I’m hoping to achieve Al. Do you have any pics? Thanks for the link, I google-image-searched the plan and came up with this which looks quite useful…

PDF

that looks fairly detailed, i do have photos (will try and post some up tonight)

i dont think you need to start doing a proper detailed design, providing you use common sense and follow the basics you will be fine.

Cheers for the pointers, plenty of food for thought. The wooden crib design looks great but not really suitable for my garden…
Going to be a busy summer, can’t wait to get stuck in!

Use a local structural engineer to design it. You may need planning permission for those works. 😕

Nooooooottt planning **** permissionnnnnn please!!!!

http://www.walesonline.co.uk/news/wales-news/girl-killed-in-wall-collapse-2166496

Maybe planning and a structural engineer is the way forward.