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My house has a sheet metal roof, and it is quite loud when it rains. I want to reduce the noise level.

I've read that an appropriate roof underlayment is ideal, but I understand that this needs to be done during installation - and I don't plan on removing the roof and putting it back. The underside of the sheet metal is accessible from the attic, so my first thought is to dampen it from the underside. I found a product called "megasorber" that is designed exactly for this- but it would cost $3000 to cover my tiny (~600sqft) house! How could I achieve this in a cost- and time- effective way?

Here is a picture of the underside of the roof:

Picture of underside of roof

My question is similar to this one, but I'm not sure that the solution there will necessarily work for me, as I need to cover a larger area, and the solution needs to be able to withstand attic heat cycles in a hot and humid climate.

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  • We need a cross-section to properly answer this. Can you sketch out the design and layers of your roof assembly? Some solutions will trap water in locations it shouldn't be, and cause you a huge problem down the road, depending on the design of your roof assembly.
    – KMJ
    Jul 26, 2023 at 18:15
  • if by underside of roof you mean the plywood and not the sheet metal itself, not much. you need to apply some kind of butyl or asphalt sound deadening material on the underside of the sheet metal.
    – ron
    Jul 26, 2023 at 18:50
  • @isherwood Fiberglass batts resting on top of the drywall ceiling. No insulation touching the metal roof.
    – Edward
    Jul 26, 2023 at 19:05
  • @ron The underside of the sheet metal is accessible.
    – Edward
    Jul 26, 2023 at 19:06
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    Please put all information in your question post. Comments are prompts for that. :)
    – isherwood
    Jul 26, 2023 at 19:10

1 Answer 1

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butyl type material... sound deadening mat...

search car sound deadening material on amazon, stuff like Dynamat

The heavier (or thicker) the mat when it is attached to the [underside] sheet metal [roof], the better is will dampen. There is also asphalt type sound deadening material, not so great for car interiors but would be great for roofing outside the living space.

I forget what I used years ago, lined the inside roof of work van that was very noisy in the rain, butyl type material that was foil backed came in 1 foot squares, ~50 lbs per box, worked very good. For your case you want to buy it by the roll, it would likely be freight delivery given the weight. What i used, once the butyl gum stuck to the metal, it does not come off so beware.

also the black rubberized spray undercoating type stuff, that you find on underside of car chassis looks like a black popcorn ceiling, will work - if applied properly and thick enough. Whether a can of that from autozone is equivalent to what ford/chevy/toyota apply when making the car i don't know.

acousti Coat Sound deadening paint, gallon $56 amazon currently, there's also paint additives (which are probably rubber chunks)

not to mention sound deadening paint for metal roof comes up somewhat automatically in google search.

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  • and you don't need to hit the entire 100% underside area with deadening material, there's some point of diminished return where going above 50%, 60%, 70% coverage will not gain anything, so do a little see how it sounds, if not desirable do a little more area and so on.
    – ron
    Jul 26, 2023 at 19:14
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    to understand the principle - find a semi large piece of sheet metal at depot/lowes that's thin enough that'll sound like thunder and be noisy when you shake it or tap it. Find whatever that can stick to it (or fasten to it) that stops that noise acceptably, and however much of that over however much area.
    – ron
    Jul 26, 2023 at 19:22

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