Van rain / condensation on the roof - solved.

[Tango]

Hi all,

Fed up with water on the inside of your van roof? Feel grim about it rusting to bits? Me too! So i've done something about it.

Basic physics: At night, the air pressure drops, the air expands, the water within decompresses, water also evaporates and floats up. This is why so many cars often have condensation inside trapped on the windscreen - a leak into the footwell, rain water on peoples shoes etc. The same applies for water in water tanks in the back of vans. I struggled with this last year and resorted to a sheet of clingfilmm over the vent with a celebrations tub on top. It reduced the problem notceably but didn't completely solve it.

Yesterday i've trialled something different. I took off the lid and put clingfilm directly over the tank and then screwed the lid back on tight so that rising moisture cannot escape. I went out there approx 10pm the results looked promising! The roof was relatively dry compared to normal (i didn't do a perfect job drying it but did get most of it).

This morning i've been out there again, still got a dry roof. It's a simple trick, hopefully it will save some of you some frustrations!

Clingfilm over the top of the tank with the lid screwed on tight over the clingfilm:



Rising mosture is trapped inside the tank under the clingfilm - although this pic doesn't show it brilliantly, i could see loads of moisture



The result is no rain waiting to fall!



My hose is still connected along with the pump, it's literally just the tanks air vent that is completely blocked. I hope this helps some of you. Obviously the film will be disposable each day and a new piece applied but it's a small price to pay to preserve your van.

 

[AW Services]

Hi all,

Fed up with water on the inside of your van roof? Feel grim about it rusting to bits? Me too! So i've done something about it.

Basic physics: At night, the air pressure drops, the air expands, the water within decompresses, water also evaporates and floats up. This is why so many cars often have condensation inside trapped on the windscreen - a leak into the footwell, rain water on peoples shoes etc. The same applies for water in water tanks in the back of vans. I struggled with this last year and resorted to a sheet of clingfilmm over the vent with a celebrations tub on top. It reduced the problem notceably but didn't completely solve it.

Yesterday i've trialled something different. I took off the lid and put clingfilm directly over the tank and then screwed the lid back on tight so that rising moisture cannot escape. I went out there approx 10pm the results looked promising! The roof was relatively dry compared to normal (i didn't do a perfect job drying it but did get most of it).

This morning i've been out there again, still got a dry roof. It's a simple trick, hopefully it will save some of you some frustrations!

Clingfilm over the top of the tank with the lid screwed on tight over the clingfilm:

View attachment 26112

Rising mosture is trapped inside the tank under the clingfilm - although this pic doesn't show it brilliantly, i could see loads of moisture

View attachment 26113

The result is no rain waiting to fall!

View attachment 26114

My hose is still connected along with the pump, it's literally just the tanks air vent that is completely blocked. I hope this helps some of you. Obviously the film will be disposable each day and a new piece applied but it's a small price to pay to preserve your van.

You can use dynamat sound deadening sheet. Have it sprayed with raptor, linex

Line it with polystyrene or insulation and then board it with ply and so on 

 

[Iron Giant]

You can use dynamat sound deadening sheet. Have it sprayed with raptor, linex

Line it with polystyrene or insulation and then board it with ply and so on 

Foil bubble wrap does the job and can be applied and removed from the van roof as required very easily.

 

[Pjj]

Hi all,

Fed up with water on the inside of your van roof? Feel grim about it rusting to bits? Me too! So i've done something about it.

Basic physics: At night, the air pressure drops, the air expands, the water within decompresses, water also evaporates and floats up. This is why so many cars often have condensation inside trapped on the windscreen - a leak into the footwell, rain water on peoples shoes etc. The same applies for water in water tanks in the back of vans. I struggled with this last year and resorted to a sheet of clingfilmm over the vent with a celebrations tub on top. It reduced the problem notceably but didn't completely solve it.

Yesterday i've trialled something different. I took off the lid and put clingfilm directly over the tank and then screwed the lid back on tight so that rising moisture cannot escape. I went out there approx 10pm the results looked promising! The roof was relatively dry compared to normal (i didn't do a perfect job drying it but did get most of it).

This morning i've been out there again, still got a dry roof. It's a simple trick, hopefully it will save some of you some frustrations!

Clingfilm over the top of the tank with the lid screwed on tight over the clingfilm:

View attachment 26112

Rising mosture is trapped inside the tank under the clingfilm - although this pic doesn't show it brilliantly, i could see loads of moisture

View attachment 26113

The result is no rain waiting to fall!

View attachment 26114

My hose is still connected along with the pump, it's literally just the tanks air vent that is completely blocked. I hope this helps some of you. Obviously the film will be disposable each day and a new piece applied but it's a small price to pay to preserve your van.

The amount of evaporation from the tank vent forming on the roof will be minimal , the issue is the inside of the van is warmer than the outside this is causing the condensation to firm on the roof . To stop or help prevent this it needs some sort of insulation on the van roof . 

 

[scottish cleaning service]

Van inside temperature is say 10 degrees and outside is minus. Laws of physics says they must meet and condense at the dew point, its the same with houses and dew point is in the cavity. Studied it at college when completing my joinery course, actually pretty interesting. If they fail to put a vapour barrier or leave big holes in it then you get dew point in the insulation part and dry rot appears. Hard to believe dry rot can occur in a new build but it can if its badly built.

 

[Tango]

The amount of evaporation from the tank vent forming on the roof will be minimal , the issue is the inside of the van is warmer

Yet with a simple bit of cling film, my roof which was covered in water drops, now has none. The cling film however was absolutely covered in it underneath / inside the tank side though (just as the top of the tank often is). Again, you say minimal but I think you are claiming that with no actual evidence of just how much water can evaporate. I've got a sealed vent hole now and I'm now seeing no water on my van roof - none. That is not a coincidence.

As for the temperature, overnight, yeah it's sheltered from the wind (assuming there is any) but there is no heat source in there to keep the temperature above the external temperature. It's quite an old van and not exactly draft proof in the back either so from my POV this is ruled out.

Insulation on the van roof is a lot of work when you can just stop water evaporating out of the tank (and remember there is no guarantee that insulation isn't just hiding the problem). By all means put yourself to the extra expense and effort if you please but if i can save someone that hassle with a simple trick, it would be wrong of me not to mention it.

Ultimately, like it or not, if you've not tried my method, you cannot justify shooting it down. Obviously it may only work with certain wyedale tanks.

Van inside temperature is say 10 degrees and outside is minus.

If it's just been running with the heater on full yes that's possible. If it's been sat there 2 days it isn't.

 

[Pjj]

Yet with a simple bit of cling film, my roof which was covered in water drops, now has none. The cling film however was absolutely covered in it underneath / inside the tank side though (just as the top of the tank often is). Again, you say minimal but I think you are claiming that with no actual evidence of just how much water can evaporate. I've got a sealed vent hole now and I'm now seeing no water on my van roof - none. That is not a coincidence.

As for the temperature, overnight, yeah it's sheltered from the wind (assuming there is any) but there is no heat source in there to keep the temperature above the external temperature. It's quite an old van and not exactly draft proof in the back either so from my POV this is ruled out.

Insulation on the van roof is a lot of work when you can just stop water evaporating out of the tank (and remember there is no guarantee that insulation isn't just hiding the problem). By all means put yourself to the extra expense and effort if you please but if i can save someone that hassle with a simple trick, it would be wrong of me not to mention it.

Ultimately, like it or not, if you've not tried my method, you cannot justify shooting it down. Obviously it may only work with certain wyedale tanks.

If it's just been running with the heater on full yes that's possible. If it's been sat there 2 days it isn't.

I dont think  a bit of cling film will make any difference, there are a lot of factors that will cause condensation on the van roof could be atmospheric conditions have altered so it’s not forming , again the amount of evaporation from a hole for a vent in the lid will be 2-3 mm or so if you got an egg cup full of water out of that that is it . When I had cold systems I would sometimes get  a wet roof and sometimes not , now with hot systems it never happens as the tank is warm enough all the time to prevent it forming . 

Ime not shooting your opinion down and if you think it’s working for you that’s good just don’t forget to remove the cling film before working or you will cause a vacuume in the tank causing pump issues 

 

[Tango]

I dont think  a bit of cling film will make any difference,

But have you tried it? There are complex cures to a lot of problems we encounter and there is nearly always a very simple trick to solving them too.

there are a lot of factors that will cause condensation on the van roof could be atmospheric conditions have altered so it’s not forming , again the amount of evaporation from a hole for a vent in the lid will be 2-3 mm or so if you got an egg cup full of water out of that that is it

But it's accumulative and that's what you're forgetting. It will evaporate one evening and form a thin layer which doesn't dry out unless you wipe it off. Then the next night more will evaporate up onto the roof to join it, then more the next night.. and before you know it, you have rain drops up on it - remember it's not going back into the tank so it just builds up. By wiping it dry (blue paper towel is very good for this - you get a lot on a single roll) and then using clinfilm, that accumulative effect every evening is blocked. I had another look at my van roof today, bone dry again and has been now for several days.

 

[scottish cleaning service]

I thought that was the reason vans get a roof vent fitted. When you drive it spins and forces air out to open air. ?

 

[Tango]

Note the rain on the inside of the clingfilm this morning (along with a quick hole i poked in it so i could use the pump).

As you can see, it's pretty well covered - and that's after i've been driving around allowing some of it to fall back down. I also still have a dry roof!

 

Since these pics were taken, i've clingfilm'd the tank again.

 

[Pjj]

Note the rain on the inside of the clingfilm this morning (along with a quick hole i poked in it so i could use the pump).

As you can see, it's pretty well covered - and that's after i've been driving around allowing some of it to fall back down. I also still have a dry roof!

View attachment 26120 View attachment 26121

Since these pics were taken, i've clingfilm'd the tank again.

If you have been driving around then that will be water sloshing onto the cling film , not condensation ???

 

[ched999uk]

Keep us updated as it will be interesting to see how you get on.

 

[Tango]

If you have been driving around then that will be water sloshing onto the cling film , not condensation ???

Not when the tank is less than 1/6 full.

 

[Pjj]

Not when the tank is less than 1/6 full.

Whatever !!!!!!!!!!

 

[Tango]

Keep us updated as it will be interesting to see how you get on.

I certainly will.

 

[JEM]

definitely a handy tip

My van would sometimes suffer with condensation on the windscreen this was before i started window cleaning, I thought maybe i had a weeping matrix even though the coolent level was always constant, I ended up filling up a couple of tights (not mine) with rice uncooked ?

That helped but i realized the problem was i was leaving my little gas bootls from fishing in the footwell those things get really cold and produce condensation and the warmer windscreen was sucking the water onto it guess. problem solved

but when i eventually fit a tank in my van i will remember this top tip

 

[scottish cleaning service]

Note the rain on the inside of the clingfilm this morning (along with a quick hole i poked in it so i could use the pump).

Cling film is just like a vapour barrier on a timber frame house. ?

 

[spruce]

In the motor trade we often used to get complaints from car owners about internal condensation on their windows in winter. In most cases we found that people ran with the internal circulation on all the time. Although the car's interior warmed up quicker, the inside of the car never 'breathed'. Wet carpets from snowy boots and wet shoes didn't help either.

We did an NVQ in window cleaning many years ago. The course was in the winter months. The instructor had a van with internally fixed hose reels that leaked water like anything. His van's floor was pools of water. His roof rained water from condensation.

We get a little condensation on the inside of the van's roof. Its not dripping wet and is easily dried off with a towel. I maybe do this once or twice a month. If the weather is dry, I will leave the rear van doors open when parked on the driveway to allow the rear to breath.

Ensuring there is no water leaks from hose reels and pole hoses are drained of water before they are put away is important for us.  We also give the brush a good shake off to remove excess water from the bristles before putting the poles away. Another window cleaner once remarked that this was such a waste of time. But condensation isn't an issue in my van - it is in his.

Who was/is the window cleaner who used to put a shower cap over the brush head every time he put his brush way? It stopped moisture from dripping into his van.

 

[AW Services]

In the motor trade we often used to get complaints from car owners about internal condensation on their windows in winter. In most cases we found that people ran with the internal circulation on all the time. Although the car's interior warmed up quicker, the inside of the car never 'breathed'. Wet carpets from snowy boots and wet shoes didn't help either.

We did an NVQ in window cleaning many years ago. The course was in the winter months. The instructor had a van with internally fixed hose reels that leaked water like anything. His van's floor was pools of water. His roof rained water from condensation.

We get a little condensation on the inside of the van's roof. Its not dripping wet and is easily dried off with a towel. I maybe do this once or twice a month. If the weather is dry, I will leave the rear van doors open when parked on the driveway to allow the rear to breath.

Ensuring there is no water leaks from hose reels and pole hoses are drained of water before they are put away is important for us.  We also give the brush a good shake off to remove excess water from the bristles before putting the poles away. Another window cleaner once remarked that this was such a waste of time. But condensation isn't an issue in my van - it is in his.

Who was/is the window cleaner who used to put a shower cap over the brush head every time he put his brush way? It stopped moisture from dripping into his van.

Most car condensation like you say is zero fresh air flow or ventilation.

I fitted a static vent in my van roof and never had an issue with it personally.

When I get In the van on a cold or damp day I just open the windows.

Old school ROSPA advanced driving phrase, when in town window down 

 

[Tango]

Well last night (and the one before) was pretty damn cold here in my area. Went out to check the van late at night as there is always condensation on the roof in those temperatures.

None. Not a drop. The clingfilm over the tank was covered in water again and the van hasn't moved for days.

 

[Pjj]

Well last night (and the one before) was pretty damn cold here in my area. Went out to check the van late at night as there is always condensation on the roof in those temperatures.

None. Not a drop. The clingfilm over the tank was covered in water again and the van hasn't moved for days.

What part of the country are you in ??