Can anyone do this sum because I have given up

[TheMustressMhor]

Okay - so we are putting concrete slabs on a small area of the garden.

This measures 12 ft x 8 ft.

The slabs we have chosen measure 450mm x 450 mm.

My brain has fallen out trying to work out how many slabs we will need.

Even the woman in the shop got three different answers and eventually sold us 36 slabs.

I think 36 slabs is wrong.

But the fact that I am incapable of working this out is driving me mad. My brain has fallen out and I appeal to anyone who has any sense to tell me how many slabs we need.

TIA

I'd have thought you'd want 8 slabs in the 12 foot direction. If you are laying them with a grout gap between then that will fill the space, probably with a bit of trimming required. If butting them up then I would just leave the gap or make it up somehow. (If you really do have to fill the space exactly then I would have thought it better to do just over a half slab at each side rather than very thin pieces).

In the 8 foot direction I would again try and see if i could get it to work with 5 slabs rather than cutting to less than a half width (which would be even narrower with a grout gap). It just looks much nicer with whole slabs rather than cuts IMO. And is less work.

I am going to order another 14 slabs.

A round sum of 50 is what most of you have calculated.

Thank you to everyone.

DH has just been out to the garden and moved loads of pots in preparation for the Great Patio Build.

Needless to say, the cat has immediately gone out to investigate.

This thread is burning my head out. All I see are numbers

It’s definitely 54 op.

The exact number depends on whether you want a border of something else round the edge and whether the tiles break when cut. If they break, you can only use one whole tile for each part tile needed. If not, you might be lucky and get two useful pieces out of one tile.

This uncertainty is why tile sellers tell you to allow 10% extra.

To be honest, unless it had to be exactly 12 ft by 8 ft, I'd lay 48 slabs (8 slabs x 6 slabs) which gives you 11'10" by 8'10" without any allowance for gaps between slabs (a half inch gap between slabs would give you 12'1" by 9'1").

To cover the area you need 45. A number of the slabs will need to be cut to fit. This figure (45) assumes you can use the offcuts to fill in other spaces that don't need full tiles. So, for example, the area is a little under 5.5 tiles wide so you can cut one tile in two and use half for the end of one row, half for the end of the next row. This is the calculation carried out by those working out the total area and dividing it by the size of the slab.

The higher figure (54) comes from assuming that you don't use any of the offcuts to fill in spaces. So when you come to the end of a row you cut a tile in half to fill in the gap and throw the other half away. If you go with that many you will either throw a lot of half tiles away or have some tiles left over.

B&Q's calculator comes up with a suggested figure of 50. This is based on the lower figure (45) but with an allowance of 10% for breakages. I would go with that.

The fact that so many answers are being given, is NOT reassuring!

@Oblomov20

I agree. I am going to go for 50 and hope for the best

Oblomov it just demonstrates that more information is needed or the question is not specific enough - it’s not a straightforward “how many of X area fit into Y area” question. It’s not poor maths skills

As you're laying chippings around the edges it will look much neater if you just lay 8 x 5 whole slabs and no half slabs.

I'm surprised nobody has requested a diagram. Surely par for the course, like cats going out for a nosey. We had our garden landscaped, with diggers and massive skips, and every day the cat had to make her own progress report...

I think 54 as well, assuming that you need to fill every bit of that area with slabs, and that you can't reuse slab pieces after they are cut. This is using 9 slabs across and 6 slabs down.

Both of those things could be wrong, as people have said.

48 would be enough if you could fill a small amount of space on the long side with edging of some sort, as 8 across is almost enough. So then you'd have 8 across, and still 6 down, assuming no cutting.

Or, if you think you can cut well enough to reuse one slab as two half slabs, then 8 across, and 5 full rows downward, and then another 4 or so to cut in half, plus a bit of edging, so you could get away with 44.

Or, 8 full rows across, 5 full rows down, and lots of edging around and between them all, and you'd get away with 40.

Too may unknowns!

12 ft x 8 ft = 3657.6mm x 2438.4mm

you need to cover 8.91869184 m2

Your slabs are: 0.2025 m2

0.2025 m2 goes into 8.91869184 m 44.04 times...

So get 44 +extras

If you’re laying slate around it anyway you could do 5x7=35 If you can't up the order, it really won’t matter

Personally I wouldn’t arse about cutting the slabs, I’d just order whole ties& columns worth. Depending on how much spare space you do/don’t have 🤷🏻‍♀️

Ties?!? Rows

I suspect the DH will lay 35 (7 * 5 and one spare for breakages) and fill in the gap around the sides with gravel.

No don’t get 50 get 54.

In other news, we are having Stornoway black pudding for breakfast tomorrow.

how many pieces of pudding and how big is the plate?

Stornoway black pudding is the best. Was this a peace offering from your DH?

@BuzzLiteYear

One slice of the black pudding each, with square sausage, bacon, egg, mushrooms, tomatoes and toast.

Just an ordinary dinner plate.

I'm team 54!

A peace offering, ContinuityError?

Not exactly.

I am hoping that he ensures that my fried egg is dippy, though.

He has produced far too many hard eggs recently.

Can the different foods overlap? Do they tessellate?

Non dippy fried eggs? Tsk, tsk, you just can't get the staff these days.