Flashing for noise reduction

sp00k · Apr 14, 2015

Has anyone got any experience of fitting self adhesive flashing (the type intended for roofing) to the roof and side metal surfaces in a defender?

I'm intending using it as my first line of defense in a sound deadening program, but it's not cheap and I don't want it to all fall off!

Also, is it effective to cover a certain percentage of flashing, say 80/90% and then cover completely with open cell insulation or does the whole of the panel need to be covered?

I would appreciate peoples thoughts.

lynall · Apr 14, 2015

I used it in my doors and then covered that in closed cell foam, must have worked as even the wife noticed the difference, the flashing never came off but the foam started to come adrift at the edges.

sp00k · Apr 14, 2015

Sounds good lynall. I've ordered some pretty expensive high temp trip adhesive, so I'm expecting the foam to stay in place. I will also be covering everything in carpet covered ply, but I don't want to go to all that trouble for flashing to fall off.

I might just do foam and ply + carpet on the roof.

bluedog333 · Apr 14, 2015

Have heard of people using it in conjunction with closed-cell, with good results. I believe you don't need to cover the whole of a panel, just need a square in the middle ( not sure what % surface area ). Works by reducing resonance rather than trying to block sound ( as the closed-cell might ).

XRIZLAX · Apr 15, 2015

Yup, works very well. Done everywhere in me truck, definitely works. Use a hot air gun to help mould round awkward bits and helps adhere.gone a bit overboard on soundproofing tbh, I've also got 25mm thick closed cell foam under the bonnet, better than dynamat and cheaper.

timtheenchanteruk · Apr 15, 2015

IIRC the flashing changes, rather than removes the resonant frequency of the panel, to one that is less likly to coincide with engine/vehicle bourne vibrations. hence no need to slap it all over, a smallish patch will work just as well.
Closed cell works on 2 levels, it dampens any remaining resonance in a panel to reduce it, and also stops sound reflections on said panel. if theres space (ie in door panels) you can imrove thing even more by using 2/3 layers of foam in some areas (ie on the back of the door panel, if theres space, cover the full panel, then put a 2" strip down and a 1" strip on top of that) the varying thickness with cover more spectum of sound it can absorb.

CalumM · Apr 15, 2015

I put flashing then closed cell foam on my doors and roof in my series. Definitely took away the low droning noise that used to be there. Still damn loud though!

sp00k · Apr 15, 2015

Thanks for your comments.

Just as a test I've stuck a fair sized piece on the bottom of each door and noticed that they are more of a clunk and less rattly than before, so that's positive.

I think all of this is going to help, but the most successful noise elimination for me is probably going to come from reducing engine noise by fitting a disco tbox and insulation on the bulkhead side.

CalumM · Apr 15, 2015

I almost got one of these:
Vehicle acoustic engine blankets - NK Group

They get good reviews and they make them for the gearboxes too I think. The only thing that stopped me is that I have a 200di in a series and it is so close to the bulkhead that I don't think there would be any room to get the blanket down the back of it.

discomania · Apr 16, 2015

sp00k said:
Has anyone got any experience of fitting self adhesive flashing (the type intended for roofing) to the roof and side metal surfaces in a defender?

I'm intending using it as my first line of defense in a sound deadening program, but it's not cheap and I don't want it to all fall off!

Also, is it effective to cover a certain percentage of flashing, say 80/90% and then cover completely with open cell insulation or does the whole of the panel need to be covered?

I would appreciate peoples thoughts.

I used some of the stuff you buy in screw-fix for about £15, I made up strips of it and applied it in the battery box, and other areas that vibrate - inside doors etc.

I then use 12mm self adhesive closed cell neoprene foam on doors and other panels. Took a LOT of the low down drumming out. I have not finished my sound deadening or even fitted carpets back in but it's much better.

Road noise will be taken out with the thicker stuff and carpet.

zeaphod · Apr 16, 2015

I found the biggest factor in noise reduction was carpet tiles on the sides and roof in the back (90 van). Also 17mm stable matting in the front/footwells made a big difference. Both really cheap too.

Flashing for noise reduction

sp00k

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lynall

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sp00k

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bluedog333

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XRIZLAX

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timtheenchanteruk

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CalumM

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sp00k

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CalumM

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discomania

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zeaphod

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