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TOPIC: Roofing over existing roof

Reroofing Over Asphalt Roofs

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Just got an estimate for a Dura-Loc roof. Currently have two asphalt roofs. Contractor says it's OK to install Dura-Loc over existing 2 asphalt roofs. I had always heard that 2 roofs were it, then you tear off and start over. What do you think?
Guest User

1/27/2003
WHAT ARE THE ADVANTAGES, DISADVANTAGES OF A CRIMPED ROOFING SYSTEM COMPARED TO THE SCREW DOWN SYSTEM WITH THE WASHERS IN THE SCREWS. I LIVE IN FLORIDA ON THE GULF OF MEXICO WHERE HURRICANES AND SALT WATER ARE A MAJOR CONCERN. ALSO, IS THE SOLAR SHIELD ENOUGH TO HELP IN COOLING COSTS, OR SHOULD THERE BE INSULATION, AND IF SO, WHAT KIND (IE STYROFOAM VS RUBBER)? DOES THE GALVALUM WITH THE RIBBED PANEL REALLY HELP AERATE THE ROOF AND KEEP CONDENSATION FROM FORMING UNDERNEATH THE PANELS AS COMPARED TO A FLAT PANEL? THANKS
Guest User

1/27/2003
Due to their low weight and design, many metal roofs install very well over existing roofing, including over multiple layers. This includes some of the Duraloc deisgns. You want to make sure that the current roof weight and condition are not jeopardizing the structure at present. Typically, a metal roof will weigh less than what a couple of layers of old roofing have lost over the years in terms of granules wearing off and oils evaporating. If you wish, you can hire a professional engineer for a couple of hundred dollars to do a quick abalysis and confirm that going over the existing is okay. In certain areas, building codes limit to a two-layer maximum. You may need special approval for a third layer. Also, the folks at Duraloc will, I am sure, be happy to discuss your particular situation and let you know their thoughts on it. Keeping the old layers in place allows you to spend money on a better roof rather than on tear-off and disposal. It also saves time and mess and landfill disposal. It also increases the home's thermal mass. Todd Miller
Todd Miller
Isaiah Industries, Inc.

1/30/2003
Your question really touches on a lot of complex issues. I am also not 100% certain of some of the nuances of the terminology you're using. It is impossible for me to fully answer your question in this forum. If you wish, call me at my office (1-800-543-8938 ext 201) and I will be glad to discuss this in detail. Todd Miller
Todd Miller
Isaiah Industries, Inc.

1/30/2003
I've talked to several contractors about bids using metal roofing, they are several ways that they used to install using the same supplier, I'm confused on what the proper way to install over old shingles. Here is what they have told me: They place felt over old shingles and lay metal roofing over felt. Another one said that they had to put furring strips down first and then the metal roofing. One said that screw the metal down in the rib another said that they screwed it down in the flat part.I don't know which way is the correct way or who is telling the correct way to install. I don't want to get the wrong installer to put the metal roofing down on my home the wrong way.If they put furring strips down will this hold moisture between the furring and the existing shingles? Thank you
Guest User

1/24/2004
When installing a metal roof over an existing shingle/asphalt roof, is it best to install flat onto the existing shingles or to install on top of wooden strips?
Guest User

1/25/2004
There are products suitable for installation over decking and there are products suitable for installation over lathe. Some are suitable for both. You need to contact the manufacturer of the roofing and ask them these questions regarding the product you've chosen. Sorry I can't be of more help.
Guest User

1/25/2004
The answer to this question is determined by the product you choose. Contact the manufacturer and check with them regarding proper installation.
Guest User

1/25/2004
What is difference in cost between asphalt and metal?
Guest User

2/21/2004
Can anyone provide a cost comparaison between asphalt and metal?
Guest User

2/21/2004
There is a wide variety of metal roof styles, types, and prices. The same goes for asphalt shingles. That makes a price comparison very difficult. Generally, though, metal might cost as low as 2.5 times the cost of asphalt or considerably more than that, depending upon the products being compared.
Guest User

2/21/2004