When you should tear off your roof and start from scratch instead.
Shingling roof over old shingles.
Remove the ridge caps.
Shingles are designed for flat surfaces.
Leave the old valley flashing in place and install new over it.
Because asphalt shingles are routinely exposed 5 in rip down the first strip the starter course so that it is 5 in.
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.
Butt these against the bottom of the old roof s third row and nail into place.
If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing.
To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below.
Why installing new shingles over old shingles can be good.
Rather than ripping off your old roof and putting a new one down you simply add a layer of shingles to your existing roof.
When roofing over your existing shingles can be a good idea.
This involves less labor dropping.
Overlaying your existing roof also comes with its own set of pros and cons.
How to do it remove caps.
Remove air vents and pipe flashings by prying out or unscrewing the fasteners holding the fixture.
For instance instead of just one roof on your home you now basically have two.
Let s start with the good.
Use a flat pry bar.
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.
Long term effects of shingling over shingles.
Why not add new roof shingles over old.
Apart from the problems going unnoticed during the actual shingle over there are long term effects to consider as well.
No missing shingles no gaps no holes in the roof no soft spots because of water damage.
All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof.
To shingle on top of existing shingles there are a few things you want to make sure.
Doing it now will make it easier to keep the reroofing job clean.
1st and foremost your existing roof needs to be in reasonable shape.
Installation is easier than for a tear off job because you can use the existing shingles as guides for laying the new ones.
Shingle a roof over existing shingles save 75 give or take.
How to roof over existing shingles.
Use 1 5 or 1 75 inch roofing nails.
Your second row of shingles should be cut to 10 inches wide.
They don t do a good job of bridging over gaps dips or humps including the.
That s a lot of extra weight putting added stress on the roof decking.
Whether it is the right choice for you depends on your home and the condition of your roof.