What are the advantages and disadvantages of stripping the existing roof shingles off and installing new shingles, as opposed to installing new shingles directly on top of my existing roof?
This is a very common question. Stripping your old shingles off your roof and installing new ones directly on the roof sheathing will produce a better quality product. For example, the shingles will last approximately 10 to 20% longer and will look far neater. New shingles installed over the existing ones will take the shape of the old shingles and the roof will end up having a wavy appearance.The bottom line is: if your budget allows, strip the old existing shingles and install new roof shingles directly on the roof structure.
Another consideration is the number of roofing layers that are currently on your roof. The majority of roofers agree that you should have no more than two layers of roofing. Most homes have been designed to support no more than one layer of roof shingles on the roof. By installing more than one layer of roof shingles you are overloading the roof structure.
In addition, material warranty from shingle manufactures need to be taken into account. Most roofing manufacturers will not warranty their product if it has been installed on top of existing roof shingles.
Typically, despite the pitfalls, the reason many home owners choose to install new shingles directly on top of the existing roof is cost. It is less expensive as you are saving the labor to strip the existing shingles off your roof, as well as saving money by not having to dispose of the shingles at the local dump. The price saving can be anywhere from 20% to 50%.Created on 09/06/2014 Permalink