Calculations Needed Please To Build Steps In My Garden, So Who's Good At Maths?

[ladybirder]

I don't know if this is in the right category but I hope The Builder or someone like him sees this.

Right, the steps are to lead from the bottom patio (BP) to the top patio (TP).
The length of the ground between these two patios is 320cm.
The steps will comprise slabs measuring 450 x 450 x 40mm.
The bricks being used for the risers are 65mm.
The drop from the TP to the BP is 46cm.
All steps don't have to be equal, i.e. I don't mind a 2- slab deep step or two if it helps.

Can anyone tell me how many rows of steps it will take to get from the bottom to the top? Thank you, you clever people.

[jackthehat]

65mm brick plus 10mm mortar joint plus 40mm slab will give you a riser of 115mm. Thus you can have 3no. built risers with an equal step of 115m off these onto your TP.

450mm long slab plus 10mm mortar joint gives an overall length of 460mm. Thus you can have 7no. slabs in length in an arrangement that suits you; eg. 3 2 2, 5 1 1.
Hope the above is understandable.....:o)

[The Builder]

............ Jack's on the case ........ ;o)

[ladybirder]

Thank you Jack. Been trying to get my head around it but yes, I get it. You've made it so simple. OMG that's going to be a lot of slabs, steps will be circa 420cm wide.

[ladybirder]

And you TB, thanks. Any idea of quantities of sand and cement needed please?

[jackthehat]

Thanks, ladybirder. :o)

I'll leave you in the capable hands of TB for calculating the materials you need. ;o)

[The Builder]

30 slabs will give you three steps at approx 4600mm width (460cm)
27 will give you three steps at approx 4100mm wide (410cm)

Setting out the brickwork for steps is very tricky, Ladybirder. Each tread laid on one course of brick is fine. The problem comes with the two ends. Brickwork mathematics won't allow it to work out easily.

If the two ends are hidden, it can be done by laying bricks with cut bits of slab to get the right heights, but it would look awful.

Try drawing it out on a piece of paper. You should soon see the difficulty.

[ladybirder]

Now I'm getting confused TB. I thought I needed 7 rows of slabs with either 9 or 10 to a row, to sit on 3 different levels (the 3 steps), varying in depth/number of slabs according to how I decide to configure as per the 2nd para of Jack's first answer. So I'm looking at 63 or 70 slabs aren't I?
Not sure I'm understanding your second bit either. Sorry, this is not my finest hour:-( Are you saying that the length of the number of riser bricks to be used won't add up to the same length of the number of slabs to be used? So one or the other would have to be cut at each end? But then you mention heights so it can't be. Can it? Please be gentle with me.X

[The Builder]

Yes, you can have that many slabs. I was just assuming you were having one row for each step :o)

The other bit is very technical I'm afraid. The way around it is to lay the bottom bricks (first step), then lay the slabs all over. Then more bricks and slabs for the second step. Finally, more bricks and slabs for the third step.

What I meant was that you will see the ends of the slabs at each end. Not the prettiest way to do it..... and, you'll have lots of wasted slabs hidden from view, but it'll work.

[ladybirder]

TB Thank you again. I still don't get how I will have "lots of wasted slabs hidden from view" but never mind, all will be revealed when it's done, hopefully in March. The idea is to have plants spilling over the edges of the steps from the borders either side. I'll have to post a pic when it's done. X

[Sipowicz]

Just take it step by step! ;-)

[ladybirder]

LOL Sipowicz, good advice.