These shingles are instrumental in making sure the asphalt shingles are correctly laid out on your roof.
First row for roof.
Lay the second row of shingles.
The height distance up the roof of the starter slate must be at least 3 inches greater than the vertical exposure on the first course of slate.
Before you can begin setting asphalt shingles on your roof you must install a row of starter shingles.
If these first shingles are not installed correctly there will be problems with the entire set of shingles.
The sealant on an upside down three tab shingle ends up far too high up the roof to effectively seal the first course of the finished shingles.
The exposure on the first course of slates may be reduced by dropping the chalk line for the top of the second course of slates in order to increase the headlap on the starter course.
Complete the second row offset one rafter width from the first then move onto the third row and so on until the last row extends past the peak of the roof.
Set the first shingle of the second row back a half tab 6 inches 17 centimeters from the edge of first shingle on the first row and so that the bottom of its tabs just touches the tops of the cutout slots on the shingle below.
And while this shortcut did protect the roof deck at shingle joints and cutouts it unfortunately left that first course of shingles unsealed and vulnerable to wind uplift.