The 3 would be the distance measured from the drip edge the point at which the water falls from the roof to the top of the gutter.
How far should gutter extend past roof edge.
Here phil explains how much overhang a roof should have at the gutter.
Shingle installation can impact gutter performance.
If you extend the shingle another inch that would be way too much.
The configuration of the brackets allows them to fit onto the gutter only one way.
Companies like gaf have shingle installation guides usually stating that the shingles should extend no more than 1 2 to 3 4 inch beyond the drip edge.
Rschneider november 19 2014 9 14pm 15.
Here phil explains how much overhang a roof should have at the gutter.
With this arrangement downspout at the corner of the house but gutter extending beyond the corner of the roofing this means on a normal peaked roof you have a gutter extension of a foot to three depending on gable end eave overhang beyond the downspout adapter mounted as normal with an end blank on the end of the gutter.
The back edge of the gutter should tuck up behind the dripedge if you have it otherwise the edge of the shingles should extend well over the back half of the gutter so the drips cannot get behind it and rot the fascia board.
The bottom tile or slate of the roof covering should project at least half way into the gutter the ideal distance is between half way and two thirds of the way over.
If im not mistaken the drip extends from the roof about 3 4 of an inch to 1 inch.
In almost every instance gutter installers take the path of least resistance and shove the gutter right underneath the roof shingles instead.
A normal gutter will have about 1 2 3 4 of its width sticking out beyond the shingles to catch the runoff.
Since the gutters have to slope down towards the downspout this distance will increase as you get closer to the downspout.
Gutters should be hung where a straight edge laying on your roof shingles can easily extend over the front lip of the gutter this is the proper installment location for the high point of the gutter.
Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials.
A typical metal roof overhang may be 2 to 4 inches or even less.
The reason for this is that whenever rain runs down any type of roof when it gets to the lower edge it clings to the tile or slate by capilliary action this means that the water actually runs around the bottom edge and slightlly back up the rear of the tile before gravity allows it to drop into the gutter.
With that style of drip edge i was always told 1 4 inch any more willhave toubles with the gutter.
Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood.