Updated: Aug 9, 2019
So your existing shingle roof has reached the pinnacle of its life cycle and you're exploring your options... And options, you do have! First and foremost, whatever installation process you decide fits your budget and needs, you want to make sure you're installing architectural shingle and not a 3-Tab. If you're reading this, odds are you're exiting 3-Tab Shingle has reached the end of its road. Unfortunately with shingle, there's not much you can do to help extend its live expectancy. When its gotta go... Its gotta go. You have a couple of options in regards to a new shingle roof.
Overlay Option- An overlay shingle installation is when you leave your existing roof alone, and simply install new shingle OVER it. This process is a little less time consuming than a tear-off and can help save you a few bucks. This process may not be ideal for everyone, nor is it always recommended. Though its a way to save some time and money, future repairs can cost almost double because of this process.
Ideal for sellers of real estate
Adding weight onto your roof (can cause uneven slopes)
Not able to replace (any) possible rotted plywood
Not replacing the underlayment (leak barrier)
Tear-Off Option- A tear off is almost exactly what it sounds like, this process strips your old roof down to the plywood prior to installing the new shingle roof. Though it is the pricier option, it is the most beneficial in the long run. In a sense you're benefiting from more than just new shingles.
Able to replace (any) possibly rotted plywood
New underlayment gets installed
New drip edge metal gets installed
Ideal for buyers of real estate
It is always best to weigh out your options whenever you're getting ready to spend some serious money. Aside from centralizing around the price, focus on the short/long term benefits of the two options. In summary, an overlay shingle roofing installation is ideal for those who don't plan on keeping their home for all that long. A tear-off installation is ideal for those who seek quality work that won't cause any long-term damages.