Replies

1. 
   UncleDunc | May 03, 2002 02:03am | #1

   The standard for drain pipe, and I believe for roof gutters, is 1/4 inch per foot, just a hair over 2%. Even if I lived where it rains a lot, I wouldn't see any point in pitching it much steeper than that.

   Edited 5/2/2002 7:06:22 PM ET by UNCLEDUNC

   
   

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   Edited 5/2/2002 11:03:12 PM ET by UNCLEDUNC

1. 
   FlavaDave1 | May 03, 2002 02:30am | #2

   I am refering to the cross slope (side of car to side of car).  I suspect that anything over 5% will be very annoying, but I am looking for verification or a design standard.

1. 
   UncleDunc | May 03, 2002 03:51am | #3

   I also was referring to the slope across the driveway. Presumably high in the middle and draining to both sides, unless the driveway is on a side slope. I agree with you that any more than 5% is too much. I also think that if 2% is adequate for gutters and pipes, and also for porch floors and shower stalls, now that I think of it, there's no reason to go even as high as 5%. I can't cite the standards publications, but I have seen 1 in 48 advised on this forum for all the applications above and have very rarely seen a recommendation for anything steeper.

1. 
   FlavaDave1 | May 03, 2002 05:29am | #4

   Thanks Uncle

   I have circumstances that require the maiximum slope possible (if I cut into the high side, I have to build a higher retaining wall), but I will not go over 5%.

1. 
   UncleDunc | May 03, 2002 05:42am | #5

   Ah, I missed that the first time. I just did a Google search for

   "maximum slope" driveway (across OR lateral)

   and came up with some interesting sites. I didn't check a lot of them, but I saw maxima from 8% to 18%.

2. 
   MNAnderson10 | May 03, 2002 06:00am | #6

   Uncle,

   Did you mean to say 1/4 inch per foot?

   MNA

3. 
   UncleDunc | May 03, 2002 06:04am | #7

   That's what I did say. (After I went back and fixed it.)

   Thanks for the eagle eye.

   Edited 5/2/2002 11:12:17 PM ET by UNCLEDUNC

4. 
   FlavaDave1 | May 03, 2002 07:17am | #8

   Hey Guys,

   Thanks for the info.  It looks like they call this 'crossfall', and I've gotten 5% from several sources.  My first guess appears right

   Thanks Again