Small retaining wall build questions.

[dobbslc]

I'm about to start my patio but after stringing out some lines it looks like the drop from the back of the house is bigger than I thought, I think I'll need a small retaining wall
How deep do the footings need to be? Single or double skin? It'll only be about 3 bricks high.
I'll get some photos later

 

[gaz1]

buy blocks turn them sideways and lay them on there side

 

[Miranda]

buy blocks turn them sideways and lay them on there side

Depends on the ground.

 

[dobbslc]

buy blocks turn them sideways and lay them on there side

That'll be strong but I want to use bricks as there's going to be a step up to the house as well and it's all on view.

 

[Nick DV]

That'll be strong but I want to use bricks as there's going to be a step up to the house as well and it's all on view.

Use blocks then face with brick

 

[brightspark]

if its solid ground the founds probably a foot wide and 6 inch deep single brick . its only 3 high its hardly going to get pushed sideways and the patio slabs will be on top of it

 

[Miranda]

The biggest issue, depending on the ground, will be that something underneath sinks for whatever reason. Building anything small or large on topsoil without some sort of reinforcing will most likely crack in time for a whole host of reasons, most of which are living happily in the topsoil.

 

[8ob]

Use blocks then face with brick

I think that makes sense, it may only be a few bricks high but whats being retained will need compacting/consolidating before the slabs go down and that wont be kind to a flimsy facing brick.

Bob

 

[dobbslc]

Here's some pics, excuse the mess and weeds....
The patio will stop in line with the wall with the piece of stud sticking up next to it.


A bit more grass will need to be cut back to make it slightly larger. @Miranda it's all London clay!

 

[brightspark]

well its not virgin ground so hardly likely to subside so get it filled with crush or dolly to height and compact it

 

[Wildefalcon]

I'd do a trench a foot by a foot, fill with a reasonably strong mix, and drop some steels into it, that should prevent cracking and sagging. Then some nice bricks to height. Put the clay behind the wall mixed with the hardcore, and it won't ever move.

Watch for drainage pipes, clay washes away very easily, so make sure any water is managed.

 

[voipio]

Three bricks high could raise the ground level up to the damp course? Or are you keeping the ground level as is next to the house?

 

[SierraV6]

Three bits of advice (apologies if teaching to suck eggs!):

1. Sort that pointing out;

2. Watch your DPC;

3. Do not cover those perforated bricks.

Depending on the size of the patio I’d be tempted to build some formwork and pour a slab/pad. That’s what I did although the concrete was the excess from another job so it made sense. That said I’d probably do it again as it’s so quick and won’t move as long as there’s a decent sub base. You don’t need a particularly strong mix especially if you add fibres (ours is rather over spec’d for a patio!). Remember you need an expansion gap/joint to the house.

 

[dobbslc]

Three bricks high could raise the ground level up to the damp course? Or are you keeping the ground level as is next to the house?

It's 3 bricks at the edge the lawn, that leaves it 150mm below the DPC.

 

[dobbslc]

1. Sort that pointing out;

2. Watch your DPC;

3. Do not cover those perforated bricks.

1. The brickie probably left those bits as it's getting covered by the step.

2. DPC is on the course just under the bottom of the byfold step.
So quite high compared to the patio level.
3. The middle one will be covered by the step but I'll extend the duct out.

I'm OK with building the wall and laying the slabs etc, it's the setting out that I'm not sure of.
Also how to get the retaining wall in the right place so I don't end up with a 2" cut of slab on the edge!
It's one of these things that you have to get right first time!

Thanks for the replies.

 

[SierraV6]

1. The brickie probably left those bits as it's getting covered by the step.

2. DPC is on the course just under the bottom of the byfold step.
So quite high compared to the patio level.
3. The middle one will be covered by the step but I'll extend the duct out.

I'm OK with building the wall and laying the slabs etc, it's the setting out that I'm not sure of.
Also how to get the retaining wall in the right place so I don't end up with a 2" cut of slab on the edge!
It's one of these things that you have to get right first time!

Thanks for the replies.

I adopted a very unscientific approach and simply measured the paving, allowed for the joints and made the slab (in my case) ever so slightly smaller. Am I understanding your question correctly?

 

[dobbslc]

You have understood it perfectly! I'm just getting paranoid
The slabs come in size of 300mm, 600mm, 900mm so if I had a straight patio it would be easy but I've got a curve in it just to make my life harder

 

[SierraV6]

You have understood it perfectly! I'm just getting paranoid
The slabs come in size of 300mm, 600mm, 900mm so if I had a straight patio it would be easy but I've got a curve in it just to make my life harder

I don't do curves haha.... If you're cutting the curves you could just mark them up after the base is built, or are you using whole slabs in a curved pattern? That's a bit more challenging, certainly to a novice like me!

 

[Pigeon_Droppings2]

Check planning rules....when we did our deck I had to check as there is a max height for a raised deck before it all get very complex (maybe speak with neighbours too just to be safe)!

Wooden deck would be a lot easier and quicker?

Retaining wall....if you are filling with permeable then I don't think you'll have big forces trying to push it over.

 

[dobbslc]

Once the new lawn is laid up against it it will probably only show a couple of bricks high so planing can do one
I really need to get my string and levels out and see what I actually need to do so I can get the materials ordered.

@SierraV6 I'm going to be cutting the slabs myself that's why I just had to by 2 Stihl saws....