Patty Bowermaster
8/15/2011
We live in a house that was built in stages over a 25 year period, completed in mid 1960's. Each section has a raised seam tin roof, most of which is installed directly on rafters with insulation rolled between the rafters but nothing between the rafters and metal. Condensation and leaks where the sections have been added have been problematic for a while. We are preparing to replace the roof and have selected a metal roofing system. Question: should we remove the existing roof and put new plywood down as an underlayment, or can we install the new roof over the existing roof? Concerns: we have been advised by three different people who have experience with this system: the retailer says there is no issue with installation over old roof; contractor says it can be done, but the old roof seams will have to be flattened, and a third gentleman says that the two metal rooves will increase "sweating" and condensation. Your thoughts?
Todd Miller
Isaiah Industries, Inc.
8/15/2011
Since you have existing condensation issues, I would definitely take this opportunity to remove the existing and install decking and underlayment. I would also encourage you to look for the possibility of increasing insulation and ventilation.
Eric Novotny
An informed customer is the Best Customer!
8/15/2011
+1 I would not put a new roof down without first addressing the source of the issues. It is entirely likely that you could put down the new roof over the existing and exacerbate the problem rather than repair it. Check the insulation and envelope layers and add ventilation. You will be much more happy in the long run.
Guest User
8/30/2011
My house was built around 1906 and my roof is either metal or tin. I know it needs to be painted/sealed because of a couple spots that drip when it rains alot. But, my husband wants to put shingles over the metal roof, is this even possible? isnt metal roofs better than shingle roofs?
Todd Miller
Isaiah Industries, Inc.
8/30/2011
Metal roofs can be expected to have longer life, energy efficiency and generally increased weather resistance. Wow ... I do not think I would put asphalt over the old metal. For one thing it will probably void the warranty on your new roof.
Eric Novotny
An informed customer is the Best Customer!
8/30/2011
+1 Do Not do that. You will ruin the roof and asphalt is not intended to work over tin.
Guest User
8/30/2011
Oh Thank you. I have never ever heard of anyone putting shingles over a metal roof either--that is why i had to ask! If anyone has more pointers about this please do tell me. I will keep fowarding the messages to him so that he (hopefully) drops this terrible idea!
Jerry Rogerson
11/23/2018

I have an old 20' x 20' storage building that has a very rusty roof that has a few leaks. I wanted to paint it after wire brushing the rust and priming the 24" wide 5V crimped panels.

After running the side grinder wire brush to remove the rust, I looked at the roof from below and discovered a "planetarium"with small pin head sized holes over much of the roof.

Is there any product that can fill the pin holes and prime the surface for painting?

If not, can I overlay new 24" 5V crimped panels onto the existing panels? The supporting wood is in excellent condition under the existing roof.

I am trying to avoid total roof removal and replacement. I store my golf car and tools in there and want to try to preserve it. I know the ideal procedure is total replacement but am trying to save what I have by either painting or overlaying.

Eric Novotny
An informed customer is the Best Customer!
11/23/2018

If the roof is that thin and showing perforations, I think you are spending good money after bad if you are trying to fix this roof. That is just my opinion.

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