The answer depends on what lies beneath when it s time for a new roof your options are to re roof over the one you have or tear the old one off and start from scratch.
Roofing layover vs tear off.
The old roofing also has to be disposed of properly which adds to the cost.
What you need to know.
In just about every scenario you are going to be able to experience better overall results when you opt for a tear off versus a layover.
A layover typically refers to adding a new layer of shingles over the existing shingles.
To cover the old roof the missing shingles would be replaced before installing a new layer or the difference in thickness.
In roofing a tear off removes all layers of shingles and underlayment from a roofing system.
An overlay roof occurs when keep your existing roof as is choosing instead to shingle on top of it.
Higher costs on average a tearoff roofing job costs around 25 percent more than an overlay.
It takes a lot more labor to completely remove all the existing roofing material and then replace all the layers removed.
Choosing the right strategy will save you money and make sure that the roof you get matches your buildings needs.
2nd layer of shingles.
If you don t take your roof down to the sheathing you will never know if you have proper underlayment or are experiencing sheathing rot or ice or water damage.
You can t examine the decking to determine if there is any damage that needs repaired.
Here is a scenario we hear about all the time.
Replacing a roof is not what many people want to spend their hard earned money on.
This contractor told me i don t need to tear off my existing shingles when we re do our roof we get it.
It s good to know that you can only choose this option if your roof has not been overlaid previously.
When the roofing company you hire tears off your existing roof and then puts on an entirely new roof.
In general it is not a good roofing practice to overlay a traditional asphalt shingle roof versus a complete tear off and replacement with a new roof for the very reason you stated.
Tear off or re roof.
Most codes allow two layers of shingles before tear off is required.
While some municipalities allow by code a second layer we do not recommend it.
Dave law last updated january 24 2020.
Why you would opt for a tear off.
The tear off method is exactly what it sounds like.