Building cut-out steps

[Dooradley]

Hoping to get a bit of advice about the best way cut out steps in my garden.

See attached photo: the lawn is raised with a retaining wall. I want to cut out part of the wall and build 3 or 4 steps going up onto the lawn.

Img: showing approx. area for steps - H70cm, W200cm, D120cm

Cutting out the wall is no problem. But as far as I can see, I have two options for creating the structure for the steps:

(1) Do I need to dig out the lawn and everything underneath down to level with the patio in order to build back up with foundations, a retaining wall, and then the structure for the steps?
(2) Or, is it possible / safe to dig out only what is needed for each step (allowing for foundations on each), and a smaller edging / retaining wall around this?

Or I may be completely off-track, in which case please tell me!

Thanks for any advice.

 

[Himaginn]

You can do stepped foundation for your return walls, which should be toothed into your existing walls for strength and aesthetics.

If you cast your steps in one go, you can also do stepped foundations. Excavate below the existing patio to provide a retainer to prevent the steps sliding forward.
When you're planning heights, etc of steps, consider if you will be facing the treads and risers with anything, say slabs on the treads, bricks on the risers, and allow for these in your concrete dimensions. E.g if you're going to face the treads with slabs, make your lowest step shallower to allow the slab to make up the difference, so that it'll be the same height as the rest.
Slabs on the risers could overhang the concrete riser a little, to hide any facing to the risers.
The rest of the steps can all be the same height, if they'll all be faced with slabs.
Then consider your highest step, how will the steps terminate, level with ground level, level with a slab set at ground level, etc. Plan your highest, or highest but one step, so that all the steps are the same finished height.

 

[r896neo]

Himaginns advide is spot on however you are going to run into problems depending on how the wall was built. The wall may be thicker at the base than at the top and because the wall was built and then back filled the ground behind will be crappy fill and so unstable for foundations. It will be clear the difference once your into virgin ground again and you can start stepping up your footings at that point. The same is true for the risers athough they are less critical as they will be retaining very little.

 

[Himaginn]

Judging by your dimensions, I assume you've calculated for 7 risers @ 100mm each and 6 treads @ 200mm each, with the top tread at top ground level. I think that seems to give an easy, shallow steps in a garden environment, good for kids, and older adults, and possibly negotiating steps carrying stuff.

 

[Dooradley]

Thanks for the advice so far.

I'd actually been thinking of 4 steps: riser 150mm tread 300mm with the top step at the top ground level as you say (the lawn level is actually 65cm, the wall goes above it currently). That was based on recommended measurements I'd seen elsewhere. Not decided as yet though.

Can you give me any pointers on the type of wall I will need around the edge - my end goal is to render it smooth (and the existing wall) and top it with coping stone. Does it need double brick, or would I do it with breeze block?

And for foundations - I've read they should be min 150mm deep and twice the width of the wall. Any thoughts?

 

[London Mike 49]

Probably all you need is on the paving expert site , so here is a link to the steps page but there is more on the sleepers page.

http://www.pavingexpert.com/featur01.htm

Mike

 

[Himaginn]

Yes, sorry, treads at more than 200mm are better. I was looking at mine and guessed 200mm, but I've just been to measure them and they're 400mm. It must have been the angle I was looking at them from the window.

My risers are 115mm, and it makes for very easy going steps.

If the ground level is 65cm, then you could go for 130mm risers, that'll be 5 risers, 4 treads, at 300mm.

I would do the return walls the same as your retaining wall. I wouldn't render, I prefer the brick. I'm not sure how the render will perform on a retaining wall.
Yes, your foundations will be fine, as r896neo said, they won't be doing much, but they will add strength to your main retaining wall.

 

[r896neo]

6'' steps are fine, 7'' starts to feel tall. The less you have to build the better.

The retaining wall at the side needs to be a decent structure, 9'' ideally. 4'' really wouldnt be up to it. I would definately build it in 9'' brickwork, Render on retain walls is fraught with problems.

As for footing i'd aim for a foot wide and 6 inches thick. It needs to be tied in to the main wall and would be much better properly toothed in by removing bricks/ halfs

The footings for the risers can be small and do very little.