Minimum soil pipe slope from lavatory?

[KillingTime]

Hi,

I'm thinking of putting another bathroom in the first floor of my house. The new bathroom will be on the opposite side of the house to the side that has all the waste drains for the other bathrooms.

I've got all my FF floors up at the moment and I could run the big toilet waste pipe parallel to the joists to the side of the house that has the drain services.

Got a 220inch travel from one side to the other and 7.5 inch high joists.

The soil pipe is quite wide so that leaves me with a 3 inch approx drop over 220 inches.

Will this incline be too shallow?

Normal (ground) drains are quite shallow. Perhaps this will work. Can't find any info on google about min declines...

Thanks.

 

[kevplumb]

4"" IE 110mm 1in 40

 

[KillingTime]

Thanks.

 

[andymarshal]

If you cant get the fall, then maybe you can screw some 3x2 to the joists to lower the ceiling, thats how i did it. Dont use a saniflow

Andy

 

[Nige F]

1in 40 is an historical rule of thumb for outside drains .....I personally would go for it and put in one acess point for rodding if needed