1 in 30 or 1 in 40

1 in 30 or 1 in 40 - drains

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SidKnee - 26 Sep 2005 12:49 GMT

I have been asked by a building inspector to create a fall of "1 in 40" in
my bathroom to act as a shower area (1200 x 1200). I can make it slightly
more steeper if I wanted. Can anyone tell me what this means 1 in 40 and
what would be a little more steeper?

For the front door ramp I have been told to have a fall of "1 in 12" and
then gradual until I reach my boundary.

Thisis a little confusingfor me.

Sikney

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zenboom - 26 Sep 2005 13:46 GMT

> I have been asked by a building inspector to create a fall of "1 in 40" in
> my bathroom to act as a shower area (1200 x 1200). I can make it slightly
[quoted text clipped - 7 lines]
>
> Sikney

1:40 is 1" rise in 40" distance or 1' rise in 40' or 1/2" rise in 20" etc
etc
slightly steeper would be :
1:39
steeper yet:
1:30
etc etc.

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clintonG - 26 Sep 2005 17:14 GMT

zenboom has it bass ackwards because a 'fall' is not a 'rise' although his
comments are pertinent, just bass ackwards as stated.

What the inspector wants is a slope in the floor and the ramp to ensure
water will runoff.
What he means by a 'fall' is the same as saying the slope runs downward.
Water runs downhill right? For every 40" of run the slope should 'fall' 1"
to ensure water flows downward.

The slope is very easy to visualize and the exact dimensional properties are
easy to determine when using an architectural scale, a piece of paper and a
couple of vertical and horizontal lines.

40" is 3'-4" so I suggest using a drawing scale of 1-1/2" = 1'-0" for this
task making this basic line drawing easy to read and measure. If you need
more help I recommend going in to a big box store and asking one of the
older employees in the lumber or plumbing department for help as most of
them have some experience reading or creating basic scaled drawings and can
help you draw to scale or determine the correct slope which the inspector is
referring to as a 'fall.'

<%= Clinton Gallagher
METROmilwaukee (sm) "A Regional Information Service"
NET csgallagher AT metromilwaukee.com
URL http://metromilwaukee.com/
URL http://clintongallagher.metromilwaukee.com/

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RicodJour - 26 Sep 2005 18:29 GMT

> zenboom has it bass ackwards because a 'fall' is not a 'rise' although his
> comments are pertinent, just bass ackwards as stated.

Semantics. The inspector has it backwards anyway. You start at the
drain and work your way up, not at the edges and working your way down.

> What the inspector wants is a slope in the floor and the ramp to ensure
> water will runoff.
[quoted text clipped - 13 lines]
> help you draw to scale or determine the correct slope which the inspector is
> referring to as a 'fall.'

The OP used metric units, 1200x1200 for his shower stall, which is
about 47.25". It's more confusing to switch units on the man than to
use different terms for the same thing. A 1 in 40 would give a rise of
15mm if the drain was centered, but you should probably bump that up to
about 18-20mm as the corners are farther away and need to rise more to
maintain that pitch.

This site presents the involved operations clearly.
http://www.thetiledoctor.com/howto/showers.cfm

R

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Homeowner Forum / Construction / September 2005

1 in 30 or 1 in 40 - drains