We hear this a lot, and the answer is yes, in many instances a metal roof be installed right over the top of another existing roof material. Actually, that's true for thousands of metal roofs - they were installed right over composition shingles and/or wood shakes with no issues at all.
If you're ready for a new roof before winter weather hits, here's what you should know about the feasibility of installing a new metal roof over your existing roof.
WILL IT WORK?
It's most appropriate for a metal tile, shake or shingle roof to be installed over one or two layers of existing roofing. Of course, both the current roof framing and decking need to be in good condition to make this possible, with no evidence of interior leaks. If that isn't the case, it's a bad move to just cover everything up with a new roofing material.
To determine the condition of your roof, start with a visual inspection. From the ground, have a look at the planes of the roof. If these planes appear straight and true from your vantage point, your roof structure is likely sound. Bad signs are things like visible depressions in the roof.
If you're able to climb up onto your roof safely, look closely for signs of weak, rotten, or compromised components, or any soft spots. If you have any doubts about the integrity of your roof, removal should be the first step in replacement. You can ask a local roofer to perform an inspection if you'd like further proof.
Remember, by adding another layer of roof covering, you'll be raising the depth of the total roof covering. This isn't necessarily an issue, but it may impact roof accessories, including things like skylights, roof-to-wall flashings, dormers, roof-top HVAC equipment and other adjoining details. To avoid potential problems, consider in advance the extra height of the new roof assembly.
NAIL & SCREW LENGTH
One of the most-overlooked elements of installing a new roof over existing roofing is the length of the nails and screws. To properly fasten the new roof material to the existing rafters or deck, your installer will need nails or screws that are long enough to penetrate both the existing layers and the structure beneath. Without them, the proper mechanical attachment of the new metal roof will most certainly be compromised - something that will become unfortunately clear after the first brisk wind! If an installer can't figure out how such secure attachment can be accomplished for your new roof, the old layers will probably need to removed first.
With the right conditions and a good installer who has found no reason that removal is necessary, installing a metal metal roof over an existing one is a good environmental choice that will save money and time. Plus, it won't affect your new roof's performance in any way. If you're considering upgrading to a metal roof and you're hoping your roof qualifies for over-the-top installation, we're happy to help. Contact Metal Roof Network today.