On Saturday, January 30, 2016 at 2:20:05 PM UTC-5, wrote:
On Sat, 30 Jan 2016 12:30:16 -0500, wrote:

On Sat, 30 Jan 2016 07:53:15 -0800 (PST), wrote:

On Friday, August 18, 2000 at 7:38:07 PM UTC-5, Charles wrote:
I need to add about 25 feet of gutter to a screen porch I'm building. Does
anyone know the magic number for how much slope it should have towards the
downspout?

Thanks a ton:

Charles
ideal is about 1/16" per foot, so roughly 1.5 inches drop in 25 feet
would do it.

That's probably the very minimum. Myself, I prefer to make it more. Part
of the reason is because it's near impossible to get the pitch perfectly
along the entire length, so you can end up getting spots that puddle. I
put about 30' of gutter on my barn, and I have about 4" of drop. It
works well, as long as I clean out all the leaves and crap that seems to
constantly get in the gutters.

Also, this barn was built in the 1950s and over time the middle of the
roof has sagged a bit. I wanted to compensate for that too.

You can get away with that much on a barn. Typical house, that much
slope would be obvious. Even if you get a puddle here and there, is
that so bad? It just dries out, doesn't it?