How much qmat

[Spldecendant 10+ year member]

I'm looking to do the whole roof of my tahoe. I'm looking to use soundqubed qmat how much sq ft do I need, I'm trying to fit it under the stock headliner as much as possible of the Matt

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[What was that? 10+ year member]

Butyl mat reduces vibration and doesnt usually require full coverage. Just hitting the roof with mat will likely not meet your expectations either way. Just mat will not stiffen the roof enough for a huge SPL improvement and mat alone does next to nothing for reducing sound. Do some research and address the sound deadening in a way that doesn't waste your time or money.

 

[Jeffdachef 5,000+ posts]

For the Roof, i'd recommend using 1/2" plywood to brace it then spray foam the gaps. Cheaper and its a lot more cost effective then 2-4 layers of deadener for bracing. Solid as wood and gained a lot of audible sound from doing it.

 

[Umbra]

For the Roof, i'd recommend using 1/2" plywood to brace it then spray foam the gaps. Cheaper and its a lot more cost effective then 2-4 layers of deadener for bracing. Solid as wood and gained a lot of audible sound from doing it.

How do you brace the metal with wood? I did my sedan trunk with CLD tiling, but it needs something more, especially on the lid and on the sides of the trunk where there are vertical "walls" between the trunk and wheel wells. I can cut the wood to size, but that's as far as I'd be able to go.

 

[C1500martin 10+ year member]

Butyl mat reduces vibration. mat alone does next to nothing for reducing sound. Do some research and address the sound deadening in a way that doesn't waste your time or money.

This. I spent like 6 hours deadening my truck, numerous cuts on hands only to feel or hear NO dofference. Shite was a waste of time and money. Theres a write up some guy did about this and has a website where you can purchase a whole proper kit to make your car go from a tin can rattle to beemer quiet.

 

[Jeffdachef 5,000+ posts]

How do you brace the metal with wood? I did my sedan trunk with CLD tiling, but it needs something more, especially on the lid and on the sides of the trunk where there are vertical "walls" between the trunk and wheel wells. I can cut the wood to size, but that's as far as I'd be able to go.

If its rattling, you have to pinpoint exact locations. If its still flexing after 1 or 2 layers of good quality CLD tiles then you might just want to seal it off from the trunk or do a 4th order blow through. You can still do wood if the surfaces are very flat and have very little bends or contours or else you'll just end up creating more rattle or just wasted efforts.. Fiberglass mat and resin is another way you can make the surfaces less resistant to flexing, how strong it is would depend on how many layers you want to do. It'll be better to do that for the trunk since there are many uneven surfaces. Normally 1 or two layers of good deadener can do the job moderately well.

 

[Umbra]

If its rattling, you have to pinpoint exact locations. If its still flexing after 1 or 2 layers of good quality CLD tiles then you might just want to seal it off from the trunk or do a 4th order blow through. You can still do wood if the surfaces are very flat and have very little bends or contours or else you'll just end up creating more rattle or just wasted efforts.. Fiberglass mat and resin is another way you can make the surfaces less resistant to flexing, how strong it is would depend on how many layers you want to do. It'll be better to do that for the trunk since there are many uneven surfaces. Normally 1 or two layers of good deadener can do the job moderately well.

Thanks for the info. I'll have to double check to see if it's rattling from adjacent pieces or if it's flexing. I'm still currious about how you actually secure the wood to the metal.

 

[Jeffdachef 5,000+ posts]

Thanks for the info. I'll have to double check to see if it's rattling from adjacent pieces or if it's flexing. I'm still currious about how you actually secure the wood to the metal.

silicone adhesives normally works fine, just need jack posts to hold it up, or anything lying around to keep it in place to let it cure. Some people use liquid nails but its pretty permanent. With silicone, you can use a thin metal wire to remove it if necessary. For my roof, I had ribs on the roof that I used to help hold it in place. If you want a faster curing solution you can use JB quickweld but it gets expensive since the tube is small.

 

[What was that? 10+ year member]

http://www.sounddeadenershowdown.com- Your best friend. Don will even tell you how well products that are not his will work. He actually recommended an MLV for me that would be nearly as effective as his for my application. His stuff is the best and easiest to use. Just doesn't always meet someone's price point.

PL400 is a very strong and very permanent. You must hold it while it dries but nothing works better IMO. The glue itself will actually stiffen the roof. You can use 1/8 plywood in layers to follow the contour of your roof. Glue each layer individually. Thats how plywood is made anyway.

 

[What was that? 10+ year member]

How do you brace the metal with wood? I did my sedan trunk with CLD tiling, but it needs something more, especially on the lid and on the sides of the trunk where there are vertical "walls" between the trunk and wheel wells. I can cut the wood to size, but that's as far as I'd be able to go.

I used Great Stuff and 3/8 ply wood. Considering time, effort, and cost this was the best solution for roof bracing I have ever used. I used the flanges on the cross members to screw the plywood to with self tapping screws. That left a space between the roof and plywood. How I filled this was by drilling holes in the plywood for access and spraying the Great Stuff in to fill the gap. This whole process only took about an hour and cost less than 75 bucks. I took a mallet to the outside and it didn't even leave a dent (I have not painted yet so the taking a mallet to it was OK).