Why it's important NOT to go over your existing roofing shingles!
When it comes to roofing, which really is not much different than anything else, it pays to do it right the first time. While the building code in Massachusetts will allow you to put up to 2 layers of shingles on your home, should you? The short answer to this is no, but first a few other important things worth discussing.
First off, whenever you decide to undertake a roofing or construction project of any kind, always make sure that you are looking for fully licensed and insured contractors. While this is common sense to many, you might be surprised how often this gets overlooked and sadly this is when homeowners generally get themselves into trouble.
In addition to the state licensing and insurance, it also imperative that the roofing installer be certified through the roofing manufacturer. This way, you can be sure to get the most qualified and experienced installer backed by the manufacturer with the best roofing warranties.
Do you know that not all warranties are the same and will vary based on the installer and their level of certification with the manufacturer? Beantown Home Improvements for example is a Preferred Contractor with Owens Corning and offers a much better warranty than most due to their certification level. You can find them along with other contractors on the Owens Corning Roofing Contractor Network. Virtually every roofing manufacturer has a database like this that you can search for qualified installers.
Ok, now that you have the info to prepare for this project, let’s get to it. Failing to remove old deteriorating shingles and simply laying a new roof over the old can lead to major problems down the road that can really cost you.
Picture this for a minute: you decide to install a new roof and want to save money by installing a new one over the old. From inside, the attic looks alright, no major staining or visible rot. You put the new roof on and somewhere down the line you notice mold forming inside the attic and maybe a leak or two. You call the manufacturer to file a warranty claim and they tell you that you don’t have a warranty because you didn’t strip your old roof. WHAT? Total nightmare, right?
So let’s break this down. Maybe you always had a leak that simply never made it through all of the layers of plywood and was slowly rotting the topside. Only now is it coming through and visible from the inside. The issue now is that since you have 2 layers of shingles on the roof, finding that leak will be near impossible as in some cases where the leak presents itself is not where the water is coming in. Now you have to find the leak and deal with the mold, which can be a costly remediation.
And as far as trying to file a warranty claim, every manufacturer that I am aware of states in their legalese that the old roofing MUST be removed. Here is a snippet for example from the Owens Corning warranty eligibility requirements that states just that:
“Your roofing system must be installed over a clean roof deck with all existing roofing material and debris removed. Including, but not limited to felt, ice and water membrane, raised nails, flashing materials for chimneys, skylights, soil pipe boots, ridge and off-ridge vents, etc.”
I bet your roof installer didn’t tell you that did they? Of course not, they were too focused on giving you the low price that you were looking for. And all for saving anywhere from $500 - $1000 to strip your old roofing, that you’re now paying for and then some.
Simply put, do it right the first time and either pay now, or pay more later.
Any good roofer will always inspect your attic to make sure there are no leaks or mold issues and that the substrate is in perfect condition and never install a new roof without removing your old one!