One major selling point of our exceptional metal roofing is that because it's lightweight, we can usually install it over the existing roof, meaning no tear-off costs.  But often the homeowners we talk to wonder whether or not it’s a good idea to roof over the roofing that’s already in place.

For many homeowners it seems like the cheapest solution, and something that they are seriously considering, but without taking into consideration the good and bad sides of this decision, it’s impossible to make the right choice for your own home.

(One thing we want to point out is that this post focuses on metal roofing. If you're talking about re-roofing with asphalt, there are building codes that limit this option, since asphalt roofing is heavy.) Avoiding a Roof Tear-off Is Good for the Environment

One of the biggest benefits of installing new roofing over the existing stuff is that it’s better for the environment. Not having to dispose of your old roofing means you are putting less material into landfills and reducing the amount of waste overall.

The old roofing material gets to remain a part of your home, and will even add a bit of additional protection between the elements and the rest of your house.

No Roof Tear-off Saves You Time and Money

By having your roofing contractor put new metal roofing, or another roofing material over top of existing roofing, you should lower your renovation costs considerably. It costs money to pull off old roofing and to dispose of it. Cutting out those steps will help the professional get the job done quicker, and should reduce the overall project time considerably.

So these are all positive reasons to avoid a roof tear-off.  However, there are downsides:  Leaving on the Old Roof Means More Weight on the Structure

Ideally, you only want a new roof installed over the old when you have a single layer of flat, intact roofing in place. Even though something like metal roofing is quite light, it could still add too much weight to your home’s roof system if you have a few layers of shingles installed on the roof of your home already. It’s important to consider the type of roofing that’s already in place on your home and how much additional weight your home’s roof system can take before you add another layer.

Installation is More Complicated

Installing roofing over existing roofing is a bit more complicated, because the installation must be customized to make sure that it’s secure. The roofer must make use of screws that are long enough to make it down to the wooden decking that the original roof is built on. If there are too many layers of roofing under the new roof this can be difficult to do.

It’s also difficult to determine if the original roof material is still in good condition if you leave the original roofing in place. This can lead to the roofer missing important problems with your roof and leaving you with a space that just isn’t as durable as it could be.

There are benefits and downfalls to roofing over the existing roofing of your home. Make sure you think about the good and the less desirable aspects of this decision. We can evaluate your existing roof and then help you choose the option that’s going to work best for you based on all that information.

Here at Metal Roofing and Siding of Minnesota, we can help you decide which is the best way to go for the roofing you'd like to have put on your home. Why not give us a call today for a free no-obligation consultation?