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

And to my great annoyance, DH has ordered and paid for the 36 slabs.

Suppose we need more? Suppose we will have loads of them left over?

Bah.

Are the slabs definitely 450mm x 450mm as this seems very small; are they not 4500 x 4500?

I keep coming up with 44

You'd need to convert your measurements in feet to mm to be able to divide the area by the size of the slabs. I make it that you'd need 43.88 slabs (so 44 slabs) but I might be wrong!

Definitely 450 mm x 450mm.

That is about 18 inches x 18 inches.

I make it 44 slabs ie
8 slabs by 5.5 rows

Number of paving slabs required: 45

I used an online calculator :p

www.jewson.co.uk/working-with-you/for-self-builders/preliminary-planning/calculators/paving-calculator/

I think you’ll need 44. 450 x 450 is the same as 1.5 feet by 1.5 feet. So for the 12ft length you’ll need 8, and for the 8 ft you’ll need 5.3 (round up to 5.5 as you should be able to use one slab twice (in 2 halves. 8 x 5.5 = 44

3.66m x 2.44 m = 8.93m^2 ( that's the 12ftx8ft)
Tiles 0.45x0.45m = 0.2m^2
8.93 / 0.2 = 44.65

You need to convert the 12ft and 8ft to meters. So 3.66 meters by 2.44m.

Then divide these by the size of the slabs:

366cm divided by 45cm = 8 and a bit so you need 9 for the length

244cm divided by 45cm = 5 1/2 ish so you need 6 for the width.

9 x 6 is 54

You need 54 slabs.

I got you need 50 slabs

12ft( 366cm) x 8ft (244cm) = 8.93 m2

If they’re 450mm , so 45cm sq then I work it out to 54.
Order 60 so you have some spare.

Depends on gaps between slabs as well. I come out approx 40 slabs using 45cm with 1cm gaps. But may be totLly wrong as jotting on scrap of paper.

I’ve got that you’ll need a grid of 8x5 approximately, so I don’t think you’ll have enough.

www.diy.com/help-advice/paving-calculator/Dev_npcart_100003.art

I got 44 slabs too

450mm

is close to 18" if you like old money (which I don't, but it's not rocket science)

So 12x8 = 144"x96" is 8 slabs by 5 and a third. Brick chisel might be needed.

Total slabs needed = 8x6 = 48

Ah, I've worked it out as how many of each part of the slabs you will need. If they're completely plain then you'll get away with using less. But it also depends where you start - do you want even edges all the way around? Or will you start from one corner?

I get 44. I think it’s looking like you’ve got too few.

The answer depends on if you want to completely cover the plot or not. Will you be cutting partials right get to full size?

I make it 54 too, some of which you will only use part of

What the ACTUAL fuck?

You all have the same measurements. Why are you giving me a bunch of different answers?

There must be a correct answer, surely?

1 foot is 304.8mm
So 12 foot is 3657.6mm
Divided by 450 = 8.1 slabs across

8foot is 2438.4mm
Divided by 450 = 5.5 slabs down

8.1 x 5.5 = 44.55 slabs
So 45 needed in total?

Concur with 54 as per @allthesharks. you might need to add some spares as you'll need to cut some and this can go wrong!

You need 96 square feet of slabs.
The slabs you have are about 2 1/4 square feet so you need about 45.

But the slabs won't fit exactly. So you will need 48 (laying 8x6).

Best to buy 50.