condensation 101

Now the weather has got colder i have noticed that the 101 always has condensation on the inside of the roof. Since im currently half way through fitting new roof panels due to water damage on the old one i really dont want to see this!

My car doesnt seem to have any condensation inside it in the morning - what causes it to form in the 101?

It is almost leak free now (slight drip off the roof hatch still), and all the floor/engine panels are fitted (though no sealed or bolted down).

any advice?

Reply to
Tom Woods
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This is moisture from the air condensing on the cold metal roof, you get that on Defender hard-top as well. I tried to sleep in the back of mine once but was kept awake by the dripping of the condensation on my sleeping bag!

It stops happening once the underside of the roof is covered with something, you could stick some carpet up there or something. In my

110 I used to get condensation above the load bed but not above the passenger compartment as this had headlining.

The lack of a large, cold, bare metal roof in contact with the moist air inside!

Reply to
Ian Rawlings

|| Now the weather has got colder i have noticed that the 101 always has || condensation on the inside of the roof. || Since im currently half way through fitting new roof panels due to || water damage on the old one i really dont want to see this! || || My car doesnt seem to have any condensation inside it in the morning || - what causes it to form in the 101?

Lack of headlining. A bit of insulation to keep the moist inside air away from the cold metal of the roof will do the trick. A bit of old carpet glued on would do, but something with a decent airspace and a fill of insulating material would be a better solution.

I have my self-build motorhome head on today.

Reply to
Richard Brookman

Thanks Richard and Ian.

It is currently bare metal in the back half as i'm still in the process of fitting the insulation and lining back. So i assume the condensation will stop when that is there (and hopefully not still happen behind the lining!).

At the front i have refitted the sheets. No condensation on the wood, but there was on the thin metal trim strip inbetween the sheets. I suppose there isnt a lot i can do about this?

Reply to
Tom Woods

I believe that the condensation occurs because there's plenty of fresh air to circulate to the surface through convection, bringing fresh moisture all the time. Putting a headlining there greatly reduces the amount of air that reaches the metal pretty much down to the air that's trapped between the metal and the headlining, so the condensation is restricted to the water that was contained in that small volume of air.

However when I say "I believe", you should bear the image of Kenny Everett and his "Brotherly Love" preacher sketch in mind..

Not really, I doubt you'd find that this thin strip actually causes it to rain inside the vehicle, like the bare rear roof can.

Reply to
Ian Rawlings

|| Thanks Richard and Ian. || || It is currently bare metal in the back half as i'm still in the || process of fitting the insulation and lining back. So i assume the || condensation will stop when that is there (and hopefully not still || happen behind the lining!). || || At the front i have refitted the sheets. No condensation on the wood, || but there was on the thin metal trim strip inbetween the sheets. I || suppose there isnt a lot i can do about this?

You have a "cold bridge". This can cause condensation to track within the insulation sandwich and cause a lot of rot before you can see it. It's worthwhile finding some way to insulate the metal so this doesn't happen. Even a bit of underlay glued to the metal would help. Think of a DPM in a house wall - you wouldn't tolerate a break in the membrane on the grounds that only a bit of moisture would get through. I've been doing a lot of research into self-builds recently, and I've heard of a lot of cases where even a screw that bridges the gap between the outside metal and some metal on the inside can cause terminal rot over a period of years.

Reply to
Richard Brookman

|| On 2006-11-05, Tom Woods wrote: || ||| It is currently bare metal in the back half as i'm still in the ||| process of fitting the insulation and lining back. So i assume the ||| condensation will stop when that is there (and hopefully not still ||| happen behind the lining!). || || I believe that the condensation occurs because there's plenty of || fresh air to circulate to the surface through convection, bringing || fresh moisture all the time. Putting a headlining there greatly || reduces the amount of air that reaches the metal pretty much down to || the air that's trapped between the metal and the headlining, so the || condensation is restricted to the water that was contained in that || small volume of air. || || However when I say "I believe", you should bear the image of Kenny || Everett and his "Brotherly Love" preacher sketch in mind.. || ||| At the front i have refitted the sheets. No condensation on the ||| wood, but there was on the thin metal trim strip inbetween the ||| sheets. I suppose there isnt a lot i can do about this? || || Not really, I doubt you'd find that this thin strip actually causes || it to rain inside the vehicle, like the bare rear roof can. || || -- || Blast off and strike the evil Bydo empire!

It wouldn't cause visible condensation, but that's the problem - the moisture will be there, but hidden within the structure. You'll only find out about it when you investigate a stain or a funny smell and find that the woodwork needs ripping out and replacing.

Perhaps I'm being a bit anal about this, but I assume that Tom is a Land Rover man through and through and would like to build something that will last until the next millennium :-) If you want a belt'n'braces job, insulating absolutely everything is the only option. Any cold bridge will cause rot eventually. (OK, everything is going to rot eventually, but good insulation will increase the life of the project by a factor of lots.)

Reply to
Richard Brookman

I avoid this kind of problem by not investigating stains or funny smells, nothing good ever comes of it.

Anal stains and funny smells?

Don't forget all those body and chassis cavities too, and broken paint surfaces. Rust is a total PITA. My krautwagen comes with a cavity insulation guide which is useful, it shows you where all the pathways into the bodywork are so you know that if you're sealing it, that you've not only sprayed half a panel due to some internal structural element that blocks the other half of a panel.

Reply to
Ian Rawlings

Tom Woods uttered summat worrerz funny about:

Yeahs, been there!

Firstly you will never stop it all unless you carpet the roof. Make sure you use a non flammable carpet or padded roof held up by velcro.

Sort the leak out, that is allowing water in to the truck , the more water the more condensation.

Try and find a roof vent that allows condensation up and out.

Once the roof leak is sorted the condensation will be slashed and you will only find minute amounts on the trim between pannels. This can create some interesting effects in a long cold spell!

Run the vehicle regular in the winter to air it out, though try and avoid short start stop trips.

Many caravanners suffer this problem too, if they can't get around it in a caravan you've little chance in a 101 however you can fit either a electric dehumidifier in the winter or one of those crystal doofers which you then dry out. They do help I'm led to believe.

I always try and park my 101 such that the winter sun is on the cab windows as much as possible.

Lee D

Reply to
Lee_D

Is the roof a single panel of ally ? If it isn't it could be. Steve

Reply to
steve

im using white laminated wooden sheets for my roof held up with that metal B&Q trim!

it is only a tiny leak. its actually coming in through the rivets in the top of the roof hatch i think! it is the only bit of roof i havent painted and it looks like i shouild have done!

i shall have a look at the caravan places.. wonder if my old scrapper caravan has one in it?

hmm. wonder if i can just invest in thermostat/timer switch for the eber and set that to run for 5 mins a day - though maybe an electric one would be safer for unnatended use?

got that bit covered!. it faces the sun in the morning - the 101 windows have been defrosted the last few mornings when ive gone to work when my car has still been frosty.

Reply to
Tom Woods

It is either one big sheet or a couple.. i think there may be a crossways join just behind the roof hatch. My roof has absolutely no leaks in now! - its just the hatch!

Its the rivets that held the roof cross on that make it leak.

Reply to
Tom Woods

from how over engineered the 101 ambi is it should last!.

The only rust i have to worry about is down in my chassis!

everything is already insulated by marshalls. if they hadnt put a big folding cross on the roof held on my loads of rivets i would have been able to leave the roof panels alone :(

Reply to
Tom Woods

Got a TIG ?

Reply to
steve Taylor

Would a roof vent totally prevent condensation?

my old caravan has something like this :

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in the roof.

Would any sort of atmospheric vent solve the problem? I could just drill a bog round hole and fit some sort of tube with a lid on..

Reply to
Tom Woods

IME no it won't, but it will reduce the problem significantly.

Reply to
EMB

Tom Woods uttered summat worrerz funny about:

Your going to fit a toilet to your roof?... no wonder it has condensation ...

;-)

Lee D

Reply to
Lee_D

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