Gutter counter slope is the angle point or grade change where the down slope of the curb ramp meets the up cross slope of the gutter.
Gutter pan slope.
The slope of the gutter must be transitioned from the standard 1 12 slope to a 1 20 slope.
For example if you have 30 feet of guttering the calculation is 1 4 x 3 0 75 i e.
This grade adjustment can be accounted for in the patching that is required when replacing old curb and gutter sections.
The common design treatment for a road is a concrete gutter that is built to match an asphalt lane.
There will be minimal grade adjustments necessary where the flatter gutter pan matches the existing street surface approx.
So if you have a 25 foot section of guttering you should set the downspout end of the gutter 5 8 of an inch lower 1 4 x 2 5 5 8 than the other end.
This means the downspout end of the gutter should be set 3 4 of an inch lower than the other end.
Figure x02 4 h counter slope conditions.
For roof slopes less than 6 on 12 the upper roof pan is attached to a locking strip soldered to the lower pan.
So what s the ideal amount of slope for your gutters.
The lower pan is cleated to the roof deck with the indicated clearances determined by expansion calculations.
When adjusting from 1 12 to 1 20 gutter slope.
As a general rule gutter slope is set at 1 4 inch per 10 feet of guttering.
Sectional view of wheelchair at a counter slope condition with grades indicating the algebraic differences and limitations.
See example table 8 8a.
The concrete gutter is oftentimes at a different slope than the asphalt lane and its surface is rarely flush with the lane.
Second view showing double grade break.