Best sound deadening

[Silver-Fox]

Hi all

Now the Daughter has got her new to her van a Fiat 2.3 multi jet L2h2.

I will be starting to convert it soon.

I would like to know which is the best/best value sound deadening and insulation.

What thickness etc etc.

What thickness ply or or the sheet material is used on the sides of the van and roof.

I’ve read dodo is good.

Help please total novice here

 

[Gromett]

For Sound Deadening Dodo are excellent. For insulation it is not as good as Celotex etc. But in combination you get both.

 

[Raul]

Dodo thermal acoustic liner 10mm with self high temperature adhesive. Thats what I used in all outside skin, and all doors.
Wall and ceiling board 3mm ply with vinyl.

 

[Raul]

Insulation you can use upholstery polyester wool that's fire treated and can be glues with trim adhesive to the dodo. You will need structural ribs behind the wall board to be attached to, as well as the furniture.

 

[fishplug]

The butyl sound deadening stuff (Killmat, Dynamat etc) are all pretty much the same. What makes a difference is the thickness. Cheap ones are often 1.5mm but spending a little extra for 2 or 2.5mm is well worth it.

You only need to apply patches of it on large, flat panels to dampen reverberation. There's no real benefit on the ridged surfaces on the floor and ceiling. Some people seem to think you need to cover every square inch of space with it. You really don't!

For the wheel arches and the step between the cab and the cargo bay I've used 10mm self adhesive closed cell foam (Deadsound extreme - but other brands will be just as good) I've also used it (on top of a couple of patches of butyl) to insulate above the cab headliner and into the recesses on the sides there. It's a pain to remove so it's a good idea to run any cables you might need later here e.g. aftermarket reversing camera. Don't go less than 10mm though as you need that in order to prevent condensation.

For thermal insulation PIR board is really hard to beat (Kingspan, Cellotex, etc) and I'm going to put some 25mm treated wood battens on the floor and 25mm PIR in between. I'll also use 25mm PIR on the ceiling and some of the walls. Some wall cavities will probably take 50mm (I've not measured that yet).

You then get into disputed territory where some people stuff that Dial plasic 'wool' or the Dodo equivalent into all the ribs and nooks and others say the air gap there is sufficient and that letting the van 'breathe' is more important. You'll certainly want at least some material of this sort. I used Knauff Earthwool in my last van and it was great for sound and warmth but it's quite itchy to work with. The Diall stuff seems to be popular but it's just polyester so doesn't score highly on the fire retardant stakes (but then PIR board isn't great when it's on fire either). Others use actual wool (which I'm seriously researching at the moment)

You then also get people who don't believe in vapour barriers and others that swear by them and those that believe that the reflective bubble wrap stuff is worth having (I used it in my last PVC but have seen some pretty compelling videos which suggest that you pretty much lose all the reflective property if you don't have an air gap, so sticking it to ply makes it pointless)

Dodo have spent a lot in advertising and I'm sure their products are very good. I'm also sure you can find equivalents with a lower price point - but you'll have to invest some time in research. If in doubt, pay the premium for the brand. That's what they count on! I've yet to hear anyone say anything bad about their stuff though.

Ply thickness is another one that divides opinion. I'm very weight conscious so I'll go 9mm on the walls and 5mm on the ceiling although I'll probably go a little thicker on the floor but I've yet to decide. I'm also comparing waterproof MDF as an option for the ceiling.

One thing people frequently overlook is the need to seal your ply before painting / carpeting it. I use watered down PVA glue and apply four or five thin coats to both sides and the edges. I also paint the back and edges (and possibly the front this time as I've decided I don't like 4 way stretch carpet) This will help to prevent moisture ingress and warping.

That's my opinion / experience from previous van builds but I'm sure you'll get a lot more heading your way soon!

I can recommend watching Greg Virgoe's videos on YouTube regarding insulation. They really helped me to understand it a lot better. In fact his electrical stuff is excellent too which I guess will be the next job after insulating.

If you plan to add windows, skylights, water fill points, etc then I'd personally recommend doing that as your first job before the insulation. It's a lot easier to do and you don't end up with metal shavings floating around the insides of your walls going rusty...

I'll stop now and give someone else a chance!

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[Silver-Fox]

Thanks for all the replies.

A friend of the Daughters is using the silver bubble wrap stuff from Screwfix.

I’m not sold on that idea.

 

[Raul]

Thanks for all the replies.

A friend of the Daughters is using the silver bubble wrap stuff from Screwfix.

I’m not sold on that idea.

Have a look at my build, I started with a empty shell, it can give you some inspiration for insulation and more. The van is 3.5T plated with at-least 300kg payload. Every item went in has been carefully considered, electrics have been updated since, a bike rack added and a extra window; oh and new cushions. Everything else still the same and still looking good. We been in -20C few winters, hot summers, vertical rain in the Hebrides, even a foot of snow on the roof oner night, in Northern Romania.

Stay away from heavy ply, and don't use any board insulation. You need a material to shape it to the van crevices, and ply is a weight killer. Caravan wallboard, same as in static homes, plenty of strength.

Thread 'Crafter first built'

Dec 7, 2019

Here is our take on a self conversion, crafter based.

• Raul
• Replies: 33
• Forum: Self-Build Motorhomes

• 
• 

 

[Silver-Fox]

Thanks Raul

This will be a steep learning curve for me.

Weight wise we have some wiggle room as this won’t be a full on motorhome but still needs to be livable for a least a week.

What did you mean by board insulation?

I saw a combined sound deadener/insulation that is 12mm thick.
That looked interesting.


Just looked through your build.
Spot on dude

 

[fishplug]

Caravan wallboard, same as in static homes, plenty of strength.

I'm slightly annoyed with myself for not having thought of that!

Thanks Raul - added to my list of things to evaluate. Would be perfect for the ceiling for sure. Do you mind me asking where you got yours from?

 

[Raul]

Board, like in celotex PIR, brilliant in a house but not so good in a van, unless you have square flat surfaces. There is enough bridging by the metal ribs, you need something to mould to curved and no so square spaces.

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[Raul]

Thanks Raul

This will be a steep learning curve for me.

Weight wise we have some wiggle room as this won’t be a full on motorhome but still needs to be livable for a least a week.

What did you mean by board insulation?

I saw a combined sound deadener/insulation that is 12mm thick.
That looked interesting.

That 12mm is brilliant for over cab, doors and pillars. You cut a sliver and pull it in with a string inside the pillar.

 

[fishplug]

I saw a combined sound deadener/insulation that is 12mm thick.

Closed cell foam is both sound and temperature insulation.

Ideally what you need to balance is the R value, the weight and the cost.

I think Raul was referring to PIR board (cellotex, kingspan) as 'board' insulation, but I disagree. I use it on flat panels where it is very effective and use some sort of 'wool' type insulation for the contoured areas where a flat board won't fit.

Bear in mind with any 'wool' style insulation (Diall plastic, Dodo fleece etc) that it needs to not be compressed in order to be effective. A large part of the insulation from these sorts of materials is based on the 'loft' (air that it traps).

 

[Silver-Fox]

I think @Raul was referring to PIR board (cellotex, kingspan) as 'board' insulation,

That makes sense.

I’d be happy putting Kingspan on the floor as it gives support to the overlayed ply or whatever you use.

It’s the way our Moho has been built as well.

Now you could “sandwich” it if weight not an issue or cut to go between the floor ribs or even rebate the insulation over the ribs in the floor.

 

[Happy Jack]

The butyl sound deadening stuff (Killmat, Dynamat etc) are all pretty much the same. What makes a difference is the thickness. Cheap ones are often 1.5mm but spending a little extra for 2 or 2.5mm is well worth it.

You only need to apply patches of it on large, flat panels to dampen reverberation. There's no real benefit on the ridged surfaces on the floor and ceiling. Some people seem to think you need to cover every square inch of space with it. You really don't!

For the wheel arches and the step between the cab and the cargo bay I've used 10mm self adhesive closed cell foam (Deadsound extreme - but other brands will be just as good) I've also used it (on top of a couple of patches of butyl) to insulate above the cab headliner and into the recesses on the sides there. It's a pain to remove so it's a good idea to run any cables you might need later here e.g. aftermarket reversing camera. Don't go less than 10mm though as you need that in order to prevent condensation.

For thermal insulation PIR board is really hard to beat (Kingspan, Cellotex, etc) and I'm going to put some 25mm treated wood battens on the floor and 25mm PIR in between. I'll also use 25mm PIR on the ceiling and some of the walls. Some wall cavities will probably take 50mm (I've not measured that yet).

You then get into disputed territory where some people stuff that Dial plasic 'wool' or the Dodo equivalent into all the ribs and nooks and others say the air gap there is sufficient and that letting the van 'breathe' is more important. You'll certainly want at least some material of this sort. I used Knauff Earthwool in my last van and it was great for sound and warmth but it's quite itchy to work with. The Diall stuff seems to be popular but it's just polyester so doesn't score highly on the fire retardant stakes (but then PIR board isn't great when it's on fire either). Others use actual wool (which I'm seriously researching at the moment)

You then also get people who don't believe in vapour barriers and others that swear by them and those that believe that the reflective bubble wrap stuff is worth having (I used it in my last PVC but have seen some pretty compelling videos which suggest that you pretty much lose all the reflective property if you don't have an air gap, so sticking it to ply makes it pointless)

Dodo have spent a lot in advertising and I'm sure their products are very good. I'm also sure you can find equivalents with a lower price point - but you'll have to invest some time in research. If in doubt, pay the premium for the brand. That's what they count on! I've yet to hear anyone say anything bad about their stuff though.

Ply thickness is another one that divides opinion. I'm very weight conscious so I'll go 9mm on the walls and 5mm on the ceiling although I'll probably go a little thicker on the floor but I've yet to decide. I'm also comparing waterproof MDF as an option for the ceiling.

One thing people frequently overlook is the need to seal your ply before painting / carpeting it. I use watered down PVA glue and apply four or five thin coats to both sides and the edges. I also paint the back and edges (and possibly the front this time as I've decided I don't like 4 way stretch carpet) This will help to prevent moisture ingress and warping.

That's my opinion / experience from previous van builds but I'm sure you'll get a lot more heading your way soon!

I can recommend watching Greg Virgoe's videos on YouTube regarding insulation. They really helped me to understand it a lot better. In fact his electrical stuff is excellent too which I guess will be the next job after insulating.

If you plan to add windows, skylights, water fill points, etc then I'd personally recommend doing that as your first job before the insulation. It's a lot easier to do and you don't end up with metal shavings floating around the insides of your walls going rusty...

I'll stop now and give someone else a chance!

Good info fishplug but beg to differ on Greg virgoe.
Yes he was an insulation worker and knows that to a fine degree but having seen most of his sprinter can build series I found him underwhelming and his electrical videos seemed amateurish.

 

[Raul]

That makes sense.

I’d be happy putting Kingspan on the floor as it gives support to the overlayed ply or whatever you use.

It’s the way our Moho has been built as well.

Now you could “sandwich” it if weight not an issue or cut to go between the floor ribs or even rebate the insulation over the ribs in the floor.

You do NOT need ribs on the floor, yes board insulation you can use on the floor as its flat, And I would pick the pink kingspan for that alone. You rib the floor, you rendered the insulation useless by adding upteen battens for thermal bridging. Glue the insulation to the floor then glue a 1/2" ply to the insulation: job done.

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[Silver-Fox]

You do NOT need ribs on the floor, yes board insulation you can use on the floor as its flat, And I would pick the pink kingspan for that alone. You rib the floor, you rendered the insulation useless by adding upteen battens for thermal bridging. Glue the insulation to the floor then glue a 1/2" ply to the insulation: job done.

Sorry must be a miss communication

I think the floor in the Fiat is ribbed from factory, it’s what gives it strength and stops the reverb when travelling

I didn’t explain well, my bad.