Anyone who disputes polythene take the casing off your car door. You'll find polythene! Its been used for years and prevents any condensation getting into the casing material. You WONT stop condensation and what runs down the panel, the car manufacturer has provided drain holes so it runs out! After 40 years in the motor trade i know this guy is correct!

Hello Mate, This is an interesting video for a number of reasons :D You are dead right about the insulation value of Reflectix being virtually nothing, that is very true. You are also right that it is an excellent radiant reflector, that is what it is primarily designed for. But the one thing it's also excellent at is being a vapour barrier because aluminium foil is totally impermeable to vapour. (value of 0.00) Nothing at all will get through aluminium foil in terms of water or vapour. That's why your Celotex insulation is covered in it. Whereas some polythenes are very slightly permeable (value of 0.06) depending on the thickness, grade of material and the difference in vapour pressure. Now it looks like you have chosen a good quality builders vapour barrier so you will be OK no problems, it is a good grade and thickness. You could have taken full advantage of that foil-faced Celotex and just foil taped over all the joints that would have done the trick. My question is? Are you going to remove all your wall and flooring to put a vapour barrier on there as I didn't see you do that previously? Sorry buddy, as you have titled this the truth about vapour barriers I wanted to give you the actual facts and figures so to speak. It's not a criticism mate, you know I'm a huge fan of your channel. Aluminium foil is the very best vapour barrier. 4.bp.blogspot.com/-yE9OE6--ah8/VvMEU11aTMI/AAAAAAAACS8/H201J9koo8wGYmjpvwMKpUh11ywFe8eHg/s1600/Table%2B-%2BPermeance%2Bof%2BCommon%2BBuilding%2BMaterials%2B500p.jpg

Hi mel your right about the polythene we use it in the States as vapour barrier when insulating homes I worked for a company for 15 years doing this, I can see watching KZfaq lots of vans will rot from the inside out the way they are using the foil ,keep the good work up buddy. And I liked the way you drained the water from the sills as it would interfere with the fibreglass insulation on the inside ,you will see alot of sprinter owner's doing this lol cheers mate look forward to your next vlog

That clear plastic looks like it would make it much easier to mount cladding because you can see through it. (compared to reflectix)

You sir, just saved me a ton of money. Thank you, as I'm on a very tight budget for my build.

Just brought a sprinter myself, I'm a total novice at this van building lark, your videos help alot 👍

Just starting our build and the polythene vs reflectics in your vid is the first that makes perfect sense to me

Want to know the main reasons I think every van conversion should have a small wood stove? 1: fire is a lovely addition when it's cold and much more enjoyable than a noisy horrible diesel heater or gas heater. 2: the dry heat produced from wood stoves is perfect for drying clothes etc relatively quickly and laundry in a van can be an issue when it comes to drying when it's always raining out. 3: the dry heat from the wood stove that dries your clothes very quickly also helps to keep the vans wood and insulation dry from vapour and damp issues, anyone who's used a wood stove for a while for heating and cooking will agree that you sometimes need to add moisture back into the air because the wood stove makes everything so dry. Perfect for battling damp issues.

Mel just completed are crafter did it same way as you with a vapour barrier and found air gaps above the insulation condenses,front headliner plastic bottle insulation glued to the metal surface with no gaps vapour barrier lead to no water on any metal surface....same result auto carpet glued directly to the metall...just a trial and error thing ,guess were all getting different results for different reasons,good luck with the build mel👍

Thank you so much mel for the advice of the polyethylene vapour barrier. cant wait until we see the design of your camper van. well done Mel.

Very interesting, as well as being a practical guy in a down to earth realistic way, you're pretty brainy too, figuring all this stuff out, these qualities make your videos excellent, thankyou Mel! Alan, Norfolk.

Man , I used reflectix as a vapour barrier and you are spot on with your assumption , if only I see your video before hand .

Hi Mell, Marathon Runners given foil Blankets After the Finish Line to regulate their body temperature after a race, adding Reflectics will also keep your van cool in the summer. Love your van builds. xXx

exactly how i vapour barriered mine. used thinner plastic sheet though, i'm too tight to spend, so used painters sheets from poundland and brown parcel tape to mount it....

Finally someone talking a bit of sense. I don't think people read the instruction. A bit worried about the wood burning stove, in a van lined with timber. Coming on very well.

Absolutely agree with you on reflectix. Always bemused me when people use it.

You won’t regret putting a log burner in your van mate 👍 ours is a cyclops from Glastonbury burners and it’s in our lwb sprinter. Copper is the chap for reflecting heat, it’s so good that we went slightly overboard with ours 🤣

Usefull tip with the polythene Mel. Saves money too. Look forward to the next installment. :-)

Having reflected on the reflectives value, my reflection is, that your reflection is deflected through the refractive reaction of the reflectations you create while driving down the M4 on a Sunday afternoon in the rain ;-)

Totally agree with your comments on the stupid silver bubble stuff - absolutely useless. Had several heated arguments about the stuff. Polynsheet and foil tape all the way. Currently converting a transit custom for a freind. We have a converted horsebox to a mobile log cabin. It’s lush. Keep up the videos. Love them.

Foil tape or Tuck tape is good for vapor barrier use. Thanks for supporting 🇨🇦 products 😀

Yeah, a little multi fuel burner 🙂 I think the mini cube works better with anthracite, no need to refill it every 30 - 45 minutes and will burn super clean. It will also save you from using the battery for the diesel heater. Expensive enough with shipping though, but hey! it's a little work of art! 👍👍👍

thanks Mel! I had a suspicion it was useless from what people have said! Insulating tomorrow woo and will find some of this for vapour barrier :)))

You dont need a vapour barrier over celotex if you seal the joints with foil tape. Ive had no probs at all. Your spot on about the air gap. I have a gap between the ceiling celotex and van roof. When we had 35 degree heat in summer, the ceiling inside was very cool.

And you’ll be able to cook on the stove too 👍 Well you’ve answered a few questions for me Mel, been unsure about vapour barrier.

Haha thanks for clearing that up Mel will save some a few quid 👍👍👍

Awesome, I was hoping you would do a solid fuel burner. Stayed in a Shephards hut last week with tiny log burner, my it got hot but shouldn't of been surprised as I have one indoors that heats most of the house

You're forgetting the air bubbles in reflectix material. The key to insulation is trapping air between 2 temperatures Having air bubbles in it will provide some insulation, albeit minimal so it's a better choice than polythene. Polythene is fine in houses as they are built warmer with thicker insulation, thermal blocks etc but in a thin walled van reflectix is actually a better choice. A van conversion company did proper monitored tests with the different types and combinations and the most effective combination at insulating was closed cell foam IE: Celotex or Kingspan coupled with Reflectix. The proof is in the science.

Awesome information Mel helped with my thoughts 💭 on the matter of vapour

Hi Mel. At last someone telling the truth about insulation! The industry standard specification for insulation is the R value. The Reflectix website states that their product is a radiant heat barrier that has no R rating, so useless as thermal insulation. Many people (including yourself) use Celotex which is difficult to install on curved areas and still needs a vapour barrier. The R value of 40mm Celotex is 1.8. What I use is 13 layer 'Multicouche'. This product is super flexible, has an R value of 1.9, is only a few mm thick (less when compressed) and very lightweight. If taped properly It's also a vapour barrier. It's the same suff that was designed for use in spacecraft. Not sure if it's available in the UK, but here in France it's under 4 euros a square metre. Why mess around with big Celotex boards and a vapour barrier when you can use Multicouche to do exactly the same thing? We just staple across the timber supports then tape over the joins and staples. Cladding then goes over the top - simple. It comes in 1.5m x 10m rolls. - Search: Isolant mince 13 couches.

Looking good mate. I wouldn't get paranoid about the weather forecast . They can't get 3 day forecast right 😂😂

Hi Mel, I have a fiamma fan and I wired black and red wiring onto it, in a way that seemed most obvious, the red led to fuse box, the black to ground bar, when it came to firing it up, I put in the fuse in the fuse box, the fans comes on itself, just goes super fast and can't be adjusted at all, I googled this and fiamma troubleshooting says: "fan wired wrong", did I miss something? I don't have the instructions anymore, I've googled and googled looking for a wiring diagram but no joy, I'm planning on ripping down the wood trim frame I put over the fan and getting in at the hidden wires next week to try do it properly, (it was done around 8 months ago and I forget what it looks like in there, I was reminded watching this video that you hooked up a fiamma fan in your ford transit conversion and I thought I'd run it past you while you might be reading comments on a fresh video, should the fiamma be just two wires? And maybe all I have to do is switch them or is it more complicated than that? Thanks

That silver tape...looks a bit like reflectics :) Van build is coming on well, great to see Mel

Your vans really coming on Mel, you've been working hard I see

I lived in a transit for years up in Scotland, I survived two Scottish winters in my van with no insulation or the luxury of a diesel heater, this van build I'm planning in looking for the best advice of all you experts.

A inner reflective sheet would reduce the inside heat to escape through the colder outer shell.. = Less condensation between the inner and outer layer, due to the fact that warmer air is able to contain more water. A ventilation fan is the best way to bring the human made moist out of the van. Closed cellfoam insulation prevent metal to condense, and at the same time make the stupid and heavy sounddeadening butyl mats totally unnecessary. If you compare metal with deadeningmat and cellfoam to only cellfoam, the best result is with only cellfoam! Every "wool-like" insulation will collect moist between the structure (no matter how waterproof the material it self are) and eventually sag. The water collected will eventually develope bacterias and harm you. Also, all wood should be sealed with paint/stain to prevent it from soaking condens water, and eventually create harmful bacterias. Every screwhole should be filled with polyurethane glue to prevent unwanted wear between different materials.( Everytime you drive you create earthquakes.) Weekend campers would not be affected as fast as full time campers. ;-)

Forgot to say great vlogs/ blogs keep em coming

Love your videos Mel but there is so much confusion with vapour barrier. Ive just insulated with dial recycled stuff and used the bubble foil over the top...wether ive done the right thing or not i dont know. However what you are saying does make sense with what you are saying. Informative video 😊

Balls!!!! Why didn't I see this video sooner 😭....oh well first van is just the practice for the next one lol..

Log burner episode can’t wait 😊

I have found that stick pins don’t hold for long just a few months at best, especially once the sun starts warming the roof, or if under any tension, good for a temp fix though.

I’ve used 7mm closed cell insulation doubled up with reflective out the outer skin will this be ok

Nice analogy on th vapour topic ⭐️⭐️⭐️⭐️⭐️⭐️

Aww, at least I know this. Thanks Mel, I'll see how it goes either way I've only wasted £20 on foil wrap 😂 watch me do it again lol

Informative video sir... what do u think about laying moisture barrier on top of the van metal floors before the subfloor? Will that create moisture and rust the van floor?

Very informative mate🌟

Hi Mel, This is an old vid but it’s found very helpful for me. Recently bought a similar product but mixed with plastic. It’s 6 mil plastic sheeting from King frost. I’m wondering if you’d think the plastic would be an issue if it can reach melting point? Doesn’t seem like a big concern but I’d love to hear your thoughts. Thank you for the informative post! Jake

Hi Mel, really enjoying the build videos it means so much to us novice van builders! Which polythene sheet did you use as the barrier please? Keep the videos coming :)

Great tips MEL great video well done.👍🇬🇧🍺🤘

hey Mel, whats your thoughts on sound deadening mat, stuck on the panels before insulation? worth it or not?

Here's a question what happens when you put a screw through the cladding and then it will rip the plastic membrane

After insulation, I was wondering if using `packaging bubble wrap`and a `commercial grade tin foil` used in cooking + foil tape would do the trick as a vapour barrier to save on costs compared to buying Reflectix? - another question to all you van owners;- Given that moisture is generated due body heat/cooking etc inside camper vans, are there advantages or disadvantages in using wood or other materials to line the inside of the vehicle?

Love your videos Mel thanks, just a quick question for you about the vapour barrier, what if the side trim on the van leaked at some point and on a hot day surely the barrier would hold the vapour from escaping, just a thought, Cheers Dave

Good video buddy . Subscribing 👍🏻👍🏻👍🏻

I actually bought some with a quarter inch foam core with R8 value instead of the typical bubbles.

Love your vids Mel, loads of good tips! Quick question (serious one this time!).... is a moisture barrier needed? I ask because I've seen and read different schools of thought for and against it. Would not having one let the van "breathe" and would the recycled plastic insulation still go mouldy if moisture got into it?

Mel! thans for your videos they're so informative!! Can I ask how you insulated your floor? wanting to save as much head height as possible. Ok for me as 5"3 but my partner is 6 foot! thanks

Id also like to piont out that blue tuck tape is suitable for vapor barrier, and a fraction of the cost of foil.

i wish you had this video 9 weeks ago mel. lol i used reflectix. at greater expense.

Where does the water run off to if it collects & puddles on the top side? Does it just run down to the side walls?

can't wait to see the log burner going in 👍

HimMel, thank you from California. I like your van can you tell me how you did that nice stainless silver paint look in the inside i see. Looks like silver, thank youu

hmmm a log burner. I once thought about it on a boat that I used to live on, but with the firebox is so small you can't bank it to well to go to bed at night. Now I have heard in the UK their are compressed wood/wax logs that are more dense and will burn longer... makes ya think about it.

Hello Mel do you have a link to the plastic sheet I don’t want to get the wrong one thanks 🙏🏽

i will share this video to help others choose.

Would a sheet of reflectix attached to a roof rack help keep a van cool in summer?

Hi mel, just going through some of your old videos for ideas. Was wondering why you used polystyrene insulation on the floor but changed to celotex for the roof?

Wish I’d seen this before sticking sound deadening, deflective, and thermo fleece all bonded down the cladding over. Can’t reverse this without big expense and masses of work. Where do I go from here?

Hi mate, was wondering, was thinking of using this as a vapour barrier but wanted to carpet my walls, is it possible to carpet over it?? Thanks in advance!

Can you please show us how you do stuff rather than describing how you did it? It's all going over my head. Thanks.

Do you puncture the vapour barrier when your fitting the ceiling ?

So, does that mean when i stuck my tin foily bubble wrap stuff to the back of my ply board before attaching , i actually done the right thing because there is a space between it and walls of van. The depth of wood frame 1" ? Michelle.

Hi Mel, you should have made a video on making your bed. Then you would have known what you’d done.

You ever had a problem with vapor molecules??..I do constantly.!!..I made a video on vapor molecules prevention if you wanna check it out!!..you have some quality content here my friend👍

I wonder if gold solar blanket material could be used. It was invented just in time to be wrapped around the Lunar Module to insulate against the heat and cold of the moon. Although probably $10,000/ metre!

Good morning Mel. Fantastic vid's mate,really getting useful info from these. @1:35 what are those 'spikey things' called ? I'm going to need them for my roof/ceiling,cheers mate,and all the best.

Hi Mel liked your idea for the tap using air pressure. When is the video

Where will the chimney go on log burner if you already covered the ceiling with plastic and insulation?

Can I also use this plastic on the flooring before I put the floor board down?

Did you put the pollyfilm on the sides as well as the roof?

What happens to the vapour once its get to the barrier ?

Ok here we go ! Vapour barriers! The vapour barrier you are using is plastic and will not breath so therefore the humidity and condensation build up within the van will hit the plastic and run off the walls and roof to the inside of your van. The same can be said of Reflectix. You will get the same reaction as you would if you left all the bare metal showing. For instance, but don't try this, put a plastic bag over your head and breath and then look at the moisture running off the bag inside from your breath. LOL please don't do this without supervision.

Hi Mel, I agree with your reflectix criticisms. ...Also, what do you as regards to insurance with the wood burner. I've spent many an hour searching for affordable insurers that will cover such burners, and indeed the chinese heaters. Obviously you have to declare them as modifications on your insurance as an after market heat source. Did you have difficulty insuring them?

Nothing screams 'Stealth Van' quite like a smoking chimney on top of it... Stick with diesel heater.

Nice one mel ..

What is the best insulation, and in what order, (from home depot?)

Unfortunately a sprinter will rot no matter how you line it out. I enjoy watching yours and other people's content but I don't get this obsession with using wood cladding and fitting wood burning stoves. Please don't fit one of those magnetic kitchen knife holders like everyone seems to do. They are lethal I an accident!

Hi Mel, I am from cold part of Turkey and in winter times we nail the plastic sheets to window frames and it realy helps keep the heat but we get heavy condensation on windows, do you know why ?

YOur polythene is great for keeping water out but what about trappped miosture? Ther will always be leaks so it needs to escape

Mel how about this idea... A periscope flu for the log burner?. 🤷🏽‍♂️

Hi mel what about your dew point above the insulation where it meets the cold metal roof ,?

Hi mate wanna ask a nice question pls I’m building a camper van ford transit jumbo 2006 will I need tell Dvla if so how I do it many thanks all the best I will keep in touch cuz I have no clue about building a camper but I will give a try many thanks again Duarte

Mel - THANKYOU! Finally someone who understands what they're talking about when discussing insulation and vapour barriers on KZfaq! Reflectix - absolutely! Vapour barrier (in whatever form it takes: polythene or foil faced board sealed up with aluminium tape) - absolutely!

What is your view on reflectics for insulation?

Rumour has it reflectix is great to protect your van if you fit a wood stove....quick rush out and buy a load 😂😂. On another note, have you considered wrapping a copper coil around the bottom of your flue for gravity fed hot water?

Your beautiful channel, my friend Hello

Vapour Barrier so you put them in to keep water out, what if it does get in ? is not then sealed in so it can rot your van ? just something ive always wondered ?

Gongratulations Mel, this is the best how to build channel that I have come across so far so I'm a new subscriber. My girlfriend is obsessed with having a camper van so now I'm up until late watching all your productions. Question, in the Transit build you cladded the roof first and here it looks like you have done the sides first? Which is best?

Geewizzers mate ..that give me the vapours ...😁oh and iffins ya gunna put a log burner in ya van make sure your planets and orbs ar align.. check with ange first ..tarrot cards may help ....😁pip pips and carryon

Just remind me, as I'm not sure I got the message.... is Reflectix any good as a thermal insulator?