# How much of a slope for paving to drain away water.

#### ey143

When constructing a patio or block drive way, how much of a slope or degree of decline does there need to be for water to drain away. If I plan to do a DIY job in the garden to save on cost of labour, just wondering how to go about doing this?

#### noseall

You want a slope of aboot 1:80.

#### ey143

Hi

What does that actually mean from a layman perspective?

For my front drive way, the council has indicated a drop of no more than 1:10

Thx.

#### JohnD

it means (just under) one inch of drop in a six-foot run.

It is easy to mark out, you just put a block under one end of your spirit level, or length of timber if the spirit level is too short.

#### ey143

Thanks, but is there a more precise calculation or measurement technique?

#### noseall

Thanks, but is there a more precise calculation or measurement technique?
Why?l

#### ey143

I like to understand things properly. Like math in school days, better to know the methodology to get to the answer.

If I have x area square paving, need to know the drop at certain distances.

#### theprinceofdarkness

You do pro-rata, 1 " in 6', is 2" in 12', . . . Or for say, 20' = 20/6 X 1" = 3.6"
Frank (O level Maths, 1964)

#### theoldun

Thanks, but is there a more precise calculation or measurement technique?

Nosey is right when he states a 1 in 80 min fall for a drive, but it can be stretched to 1 in 100 if workmanship is good, plus your fall depends on existing ground levels
A 1 in 10 fall is much to steep for a drive way unless of course existing ground levels dictate
Suggest you ignore the other posts as they are very misleadng
A 1 in 10. Divide 10 in to 1 = .100 therefore fall is .100mm in 1metre
A 1 in 40 Divide 40 into 1 = .025 therefore fall is 25mm in 1 metre
A 1 in 80 fall ditto .0125 say 12mm in 1 metre
Easy ain't it
Regards oldun

#### ey143

Hi

So for a 5m drive way, that would mean that the council will allow no more than a 50cm drop. So the photo I took in the attached link should be fine then (Type 1 MOT stage) before the block paving goes down?

http://www.diynot.com/network/ey143/albums/21651/80936

[/img ]http://www.diynot.com/network/ey143/albums/21651/80936[/img]

#### JohnD

So for a 5m drive way, that would mean that the council will allow no more than a 50cm drop.

you sound as if you actually want a big drop. Do you? Why?

#### ey143

No, not at all. I'm just new at all of this and want to make sure the guys I have used have done it correctly because its not as if I can get out a ruler and measure their work / degree of drop to ensure they have complied.

#### noseall

No, not at all. I'm just new at all of this and want to make sure the guys I have used have done it correctly because its not as if I can get out a ruler and measure their work / degree of drop to ensure they have complied.
FFS! What are you building a space craft?

#### noseall

Building work is not precise and nor do people involved in building work expect exact minute precision.