If laying three tab shingles over three tab shingles it is important to nest the new shingles against the old to create a flat surface as friedman elaborates just below.
How to starter course shingles over existing 3 tab roof.
Following the manufacturer s directions.
Nail the shingles just above the tab slots.
Use a starter strip or cut pieces for a starter course.
Rip cut the starter strip or starter pieces so that they butt up against the second course of existing shingles and are even with the front edge of the existing roofing.
To make your own use the flat solid part of the shingles and a heavy duty utility knife to cut pieces that are approximately 5 inches wide.
Cut and install shingles.
Cut and install shingles rip cut the shingles for the first course so they butt up against the third course of existing shingles and are even with the front edge of the starter course.
Their tab slots should not line up with the tab slots of the starter course if there are any.
To prepare the tabs and lay the starter course shorten the first starter shingle by 6 inches or about a half of one tab.
This should leave you with about 1 2 of the shingle left.
Damaged decking will need to be repaired before you can install any new shingles.
Attach with nails along the top edge of the strip.
To begin installing the first shingles on your roof cut off the three tabs on the shingle.
The felt should be secured every six inches with nails or staples.
Starter shingles are the initial shingle products installed on the roof just before the first course of the finish shingles which will comprise the visible parts of the roof.
If you are using a power nailer drive nails by squeezing the trigger and bouncing the nailer s tip onto the shingle.
Install a layer of roofing felt over the roof before you begin installing the new shingles.
To attach a 3 tab shingle align it with the layout line and drive nails 1 2 inch above the cutout slots including the half slots at each side.
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Every roof has to start somewhere and that somewhere is at the appropriately named starter shingle also called starter strip.
Using a utility knife cut them off at the bottom of the adhesive strip.
Step 3 cover the old shingles.
Damaged shingles should be removed to check the decking for problems.
This process starts with a 5 inch starter strip fit along the eaves and set against the second course of existing shingles see figure 2 16.
Place the top of each starter shingle firmly against.