To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below.
Shingling a roof over existing shingles.
However you ll want to check with your local building department before you make any decisions.
In a reroof job a special type of drip edge flashing is installed at the eaves and rake to wrap around the existing shingles.
To shingle on top of existing shingles there are a few things you want to make sure.
Let s start with the good.
Remove air vents and pipe flashings by prying out or unscrewing the fasteners holding the fixture.
The starter course or strip is rip cut so it butts up against the third courseof the existing shingles.
If the job is done correctly with the new layer of shingles laid flat over the existing shingles the old roof cushions the new one and serves as a secondary barrier should wind or water ever break through the new shingles.
No missing shingles no gaps no holes in the roof no soft spots because of water damage.
When roofing over your existing shingles can be a good idea.
How to do it remove caps.
Building officials in some areas will only allow a re roof over one layer of shingles while officials in other places may allow you to place the roof over two layers of shingles.
Because asphalt shingles are routinely exposed 5 in rip down the first strip the starter course so that it is 5 in.
You can save money because there s no dump fee for removing your old roofing and there s no need for additional felt paper over the old roof.
Many arizona homeowners with shingle roofs do decide to roof over their existing shingles because.
Contrary to what might seem like an obvious benefit having multiple layers of shingles does not necessarily make a roof more waterproof and it often creates its own problems.
So why would you lay new roof shingles over old.
Remove the ridge caps.
Why add new roof shingles over old.
Position one of the uncut shingles on top of a trimmed shingle.
Mark the location of the top of the uncut shingle on the felt.
The rest of the shingles are full width.
Why installing new shingles over old shingles can be good.
Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option.
The uncut shingle should hang a quarter of an inch over the roof edge.
A properly installed layover roof can look and function as well.
All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof.
Use the chalk line to mark the line at that spot across the roof.
If a shingle is.
If you have any of these things then you need to repair them first.
1st and foremost your existing roof needs to be in reasonable shape.
Leave the old valley flashing in place and install new over it.
However both of these benefits have caveats.
When you should tear off your roof and start from scratch instead.
Its front edge is even with the front edge of the drip edge.
Doing it now will make it easier to keep the reroofing job clean.