Retaining Wall Steps

[Art Martin]

Hi All.

I'm hoping the knowledge trust can pass on some information, or a web link to some information on building solid steps in a retaining wall up to the next terraced level. Just like the attached pic.

I would imagine that I would build the stringers on either side with increasing heights of besser blocks or bricks, and then either completely fill the steps with concrete, or compacted soil? Any ideas?

Thanks as always!

[Bleedin Thumb]

You can build you steps out of anything you want. Its best to use a material sympathetic with the retaining wall or flooring of your terraces however.

If your trying to acheive steps similar to the ones in the photo IE tiled between either rendered brick or concrete walls you would build your return wing walls first then form and pour concrete or brick and pour between, then tile over.

Remember to allow for the thickness of your tiles & bed on your first and last risers.

[Blocklayer]

Try this calculator http://www.blocklayer.com/stairs
.

[Art Martin]

Just out of interest, what sort of footings would be required for the bricks if I bricked then filled with concrete? I'm looking at 1metre high. About 5 steps.

On the other hand it would be a fair amount of concrete if I simply levelled the site to flat and formed the steps from straight concrete.... so I'd say a brick "frame" would be the most economical, then fill the gaps. But you'd obviously have to build a footing for each step. Any way around this? Perhaps partly fill with compressed soil?

[Bleedin Thumb]

Just out of interest, what sort of footings would be required for the bricks if I bricked then filled with concrete? I'm looking at 1metre high. About 5 steps.

On the other hand it would be a fair amount of concrete if I simply levelled the site to flat and formed the steps from straight concrete.... so I'd say a brick "frame" would be the most economical, then fill the gaps. But you'd obviously have to build a footing for each step. Any way around this? Perhaps partly fill with compressed soil?


If you were forming and pouring you would have a sloped base of compacted fill so its not just one big block of concrete. do an internet search and you will get the idea.
If you go the brick riser way, one way (though slow) is to build the bottom riser and back pour concrete...which forms the footing for the next step once its gone off..build the riser for the next step on the slab then backfill etc etc.

As I said slow- but easy.

[pawnhead]

Build the two walls and backfill on a slope allowing for a 100mm throat on the staircase. Leave a few bricks out of the return walls where the staircase throat will be. Lay some mesh, or reo bars, and stick a few in the brick holes. Form the risers with ply backed with stiffening timber. If it's a wide span then put a stringer up the middle with stop blocks against the risers. Pour concrete, strip formwork, tile over. :2tsup:

edit: I'm happy to go into more detail with diagrams if you want.

[Art Martin]

If you were forming and pouring you would have a sloped base of compacted fill so its not just one big block of concrete....


That makes sense. So it's just a matter of laying the formwork and then concreting the steps "shape" over the top of the sloping base....I did think along these lines, but wasn't sure it how it would work.

Thanks again!

[Art Martin]

So I just want to clarify that i'm interpreting the correct terminology.

Build the retaining walls on the left and right hand side of the stairs like the pic above. Then create a sloped base from the front(bottom) to the back(top) of the steps. Add formwork at the point of the risers(vertically), and I would imagine you'd have to bevel the formwork at the bottom, or you would get a area of concrete underneath the formwork which could not be floated. But I suppose if you are tiling the risers, it would not show....Fill with concrete (with mesh at the base of each step). Remove formwork and you should have perfectly formed steps.

Is that about right!

[Bleedin Thumb]

You have described the process correctly ( except the mesh goes right along the sloping base not on each tread).

There is however one factor that I guess we all learn about by experience..........bracing the formwork!

You will end up with curved steps (or worse) if this is not done correctly.

Not knowing you abilities - I would recommend getting in someone to do this for you if you are not used to handling concrete.

At a guess (couldn't be bothered doing the calcs) you will be looking at about 1.5 tonnes (min) of concrete........thats a lot of force that is fighting against gravity.

[pawnhead]

Here's a picture:

http://i7.photobucket.com/albums/y266/holgerdanske/th_stairform.jpg (http://i7.photobucket.com/albums/y266/holgerdanske/stairform.jpg)

I've drawn a supporting stringer with blocks attached in red. This staircase is rather narrow and it's supported well enough by the 4x2s behind the formply, so it doesn't need any mid span stringers. You cut the risers out of ply with pieces of ply attached at each end as shown, then reinforce them with some solid timber cut tight between the end pieces. Level them up in the correct position, and fix by nailing through the pieces of ply at the ends.

edit: You can use the side walls to support the staircase by leaving a few bricks out and poking some reo bars into the voids. The staircase concrete will then flow into the voids and the walls will support the staircase when the concrete is set.

[autogenous]

You will need a total going first or establish a total going. A good exterior going (Tread) would be about 350 mm. A good rise would be about 175 mm.

If your going to build steps then you will build the side walls first using the total going required. Once that is done you can draw the steps on the side walls square to each other.

The simplest way would be using 200x350x500mm reconstituted limestone blocks.
Their reasonably well consistent in size. Lay the blocks on flat.
Best way is to compact by hand then screed from the base up smoothing the sand with a plasterers trowel or smooth plastic float.
Be sure to recess the next block behind the first going to give you your desired rise of about 175 or 172mm brick guage. If you plan on putting pavers as the tread then you will have to deduct the paver height to accommodate the paver plus cement to end up with top of paver (TOP) on the rise 175 from TOP at FGL on the lower TOP finished ground level (FGL)

A recon block weighs about 65 kilos. You could use Concrete blocks and fill if the recons are are too heavy.