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Using A Dehumidifier To Help Dry Out Our 'van


Big Tim

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:blink: Following problems with damp in our van(see recent post "update on damp in our 'van") I am thinking of using a dehumidifier to help dry out the small area of damp wallboards.

 

I know nothing about them!!

 

Can anyone advise about:

 

What sort of size?

 

How long would I need to use the dehumidifier?

 

Is it worth buying one or should I hire?

 

The damp is confined to a small area on the rear nearside corner, within the rear bathroom wardrobe.

 

I usually keep the van in a farm building but that doesn't have an electricity supply. I, therefore, have to keep the 'van outside our house whilst using electric appliances and would prefer not to keep it there too long!

 

The damp areas to seem to be drying out since I resealed the rails and ran a fan heater in the bathroom area for 2 weeks.

 

Thanks in anticipation for any advice.

 

Regards

 

Tim

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Sorry to say this, but I don't think that you should be experiencing damp in your van.

 

We store our van in the open during the winter months and use ours about once a month during the winter and have no problems with damp.

 

Yossa

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I have wondered about buying a small dehumidifier for the van. Its nothing at all to do with the van having damp but a caravan over winter with no heating would become damp in the same way as a house without heating would. I am lucky in so far as my caravan is in my back garden and I can put the heating on when ever I like. However it does worry me that without the heating the bunk mattresses and the curtains will retain the damp of the atmosphere. I have seem a small dehumidifier for £50 which I think would be a help.

 

David

David - Milton Keynes

Bailey Alliance 66-2 Motorhome for holidays and a Kia Venga for home.

 

Caravan Travels

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There is so much ventilation in caravans, a dehumidifier would be attempting to dehumidify the entire county. Note the photograph in Enroute (the CC Magazine) a couple of months ago of an enormous number of 4 litre milk bottles of water someone emptied out of their dehumidifier over winter.

It's something like using Aircon with all the doors and windows open

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There is so much ventilation in caravans, a dehumidifier would be attempting to dehumidify the entire county.  

44779[/snapback]

 

I've seen this written time and again whenever a dehumidifier query comes up and I don't 100% agree. Heres why: I used to use a single garage as a workshop. Single skin asbestos corrugated roof with all the air holes down the sides half heartedly stuffed with wool. Up and over door with the gap along the bottom. Single skin red brick wall. Personal side door with the usual gaps. I ran a domestic dehumidifier 24/7 and collected a lot of water. The atmosphere in that garage was very noticiably dryer and a test was to feel a piece of scrap paper lying about inside. With machine running, the paper was always dry to the touch. With machine not running, a piece of paper would be damp. Conclusive proof I think that using one is worthwhile especially as running costs are so low. I'd venture to suggest that my garage/ workshop was far more ventilated than any caravan can ever be.#

 

I think dehumidifiers are far more effective than people think.

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I've seen this written time and again whenever a dehumidifier query comes up and I don't 100% agree.

 

44788[/snapback]

 

Neither do I! We have a dehumidifier indoors at home. It's permanently switched on but controlled through a humidistat and set at 5 (on a 1 to 10 scale) which is also marked 'normal'. It runs for half an hour or so most days. I used to transfer it to the caravan for short periods, but now I've installed another small one in the van for use in winter. In the past I've experimented with two identical hygrometers, and without a dehumidifier, the humidity in the van was the same as the outside atmosphere. With this small dehumidifier running for several hours each day, it gives a humidity which is usually 10% lower in the van. Currently, humidity outside is 92%. In the van it's 78%. Proof enough to convince me that it's worth while doing.

Citroen C5-X7 Tourer+Avondale Rialto 480/2
https://jondogoescaravanning.com

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Good morning.

I use a domestic dehumidifier in my van, it is on a timer and only comes on for about 2 hrs a day, but even this is enough to draw a fair ammount of water and the van always feels dry. Beware when buying a dehumidifier that no all will operate in very cold temperatures i:e below 5 degrees C. And for all those who say "don't store your van use it" , we are not all as fortunate as you.

 

Dave

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Guest Hobbybod

As Matt says, there's been quite a discussion on the effectiveness, or not, of using a dehumidifier in the 'van.

 

Personally, I remain sceptical of their efficiency, and certainly cost effectiveness, over using a thermostatically controlled fan heater and/or 'greenhouse' heater, which is what I've used when hook-up has been available.

 

Cold winter months often have a lower relative humidity in the atmosphere than other months, so a dehumidifier hasn't got so much humidity to work on.

 

However raising the temperature in the 'van, with some air flow to the outside, will put any moisture out of bedding etc. into the atmoshere and then eventually to the outside. Such a transfer of moisture is far more rapid at higher temperatures, hence the relative inefficiency of de-humidifiers at low temperatures.

 

Neither method will keep damp at bay if it's due to any leakage into bodywork.

 

In Tim's case I'd use a fan heater and put small pin holes through the internal wall board where the damp patch is, so as to drive out the moisture trapped in the wall. Inside a wardrobe the pin holes will not be seen.

Of course the leak must be stopped first.

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Being a Heating Ventilating and Air Conditioning Engineer I can speak with some authority on this subject.

 

Humidity in isolation isn’t a problem; it becomes a problem when poor ventilation is bought into the equation.

 

A caravan is normally well ventilated, so as long as ventilation grilles aren’t blocked up you won’t have a problem with condensation or damp. .

 

In winter although ambient air has a high humidity the moisture content is very low.

 

Condensation will only occur if you have very low temperature surfaces which is at a lower temperature than the dew point of the

air.

 

If a caravan is left unheated without anyone in it both the surfaces and the internal air temperature will reach equilibrium so no condensation will occur.

 

However if people occupy the caravan they will add moisture to the air by breathing and perspiring thus raising the moisture content of the air, if no heating is added eventually condensation could occur on cold poorly ventilated wall surfaces.

 

I don’t think using a de humidifier in a well ventilated space is a worthwhile proposition as some one said earlier in this thread you are trying to reduce the humidity of outside!!

 

Desperado

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The damp is confined to a small area on the rear nearside corner, within the rear bathroom wardrobe.

 

44763[/snapback]

Hi,

I am sure someone will correct me if I am wrong…………….

One of my past jobs was a Property Manager for a large estate; some of the buildings were on the sea front and suffered with damp. I would organise contractors to solve the problem.

They would set up humidifiers (industrial) but would enclose the damp area with polythene and have the inlet enclosed within the polythene ‘bubble’.

This practise meant that only the effected area was treated. (it seemed to work!)

You may be able to adopt a similar method and save ‘humidifying’ the whole world????

I've had another think and I seem to remember them using heaters as well, which would of helped to make the moisture condensate :(

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In winter although ambient air has a high humidity the moisture content is very low.

 

Desperado

44830[/snapback]

 

So where is the litre or so of water which I pour away from the dehumidifier each week coming from?

Citroen C5-X7 Tourer+Avondale Rialto 480/2
https://jondogoescaravanning.com

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I use large bags of silica in all cupboards, and under beds etc, a little heater comes on when temps reach zero :)

 

well now I have said that I out to put them in now, as its freeezzzing out :o

 

(I also have beer in the fridge for when I go out to check it :D )

Paul B

. .......Mondeo Estate & Elddis Avanté 505 (Tobago)

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Guest Hobbybod
I use large bags of silica in all cupboards, and under beds etc, a little heater comes on when temps reach zero  :)

 

well now I have said that I out to put them in now, as its freeezzzing out :o

. . . .

44894[/snapback]

Paul, the heater is OK but silica is a waste of time unless you are prepared to keep taking it out and re-activate it in the oven.

 

Now if it's freezing there isn't any moisture in the atmosphere. So any dehumidifying method is a total waste of time.

 

When freezing, the only way to get moisture to evaporate, at any great rate, into the atmosphere from bedding and cushions etc. is to heat the 'van up!

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Paul, the heater is OK but silica is a waste of time unless you are prepared to keep  taking it out and re-activate it in the oven.

44899[/snapback]

 

Hi Hobbybod

We have an Aga so its no problem :) (and they are 1. 5kg bags) :)

 

thats why beer is in fridge :lol:

Paul B

. .......Mondeo Estate & Elddis Avanté 505 (Tobago)

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:( Thanks for the very many and varied replies to my post.

 

If I could just mention a couple of points

 

(1) I believe I have cured the problem of water ingress by resealing the 'van earlier in the summer.

 

(2) I am now trying to dry out the damp patches on the interior wallboard before decay sets in without having to remove/replace these difficult sections, ie, behind wardrobe shelves.

 

(3) Using a fan heater over a 2 week period has considerably reduced damp meter reading.

 

(4) Someon suggested using a humidifier to speed up the process.

 

(5) If I did use the dehumidifier it would be in the small enclosed area of the rear washroom closed off from toilet and rest of van by "wooden" doors.

 

Back to my original questions

 

(1) Would a dehumidifier help?

 

(2) If so what size?

 

(3) How long (how many days) should should I run it for?

 

I would be grateful for any answers to the last 3 specific questions.

 

Thanks

 

Tim

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:blink: Following problems with damp in our van(see recent post "update on damp  in our 'van") I am thinking of using a dehumidifier to help dry out the small area of damp wallboards.

 

I know nothing about them!!

 

Can anyone advise about:

 

What sort of size?

 

How long would I need to use the dehumidifier?

 

Is it worth buying one or should I hire?

 

The damp is confined to a small area on the rear nearside corner, within the rear bathroom wardrobe.

 

I usually keep the van in a farm building but that doesn't have an electricity supply. I, therefore, have to keep the 'van outside our house whilst using electric appliances and would prefer not to keep it there too long!

 

The damp areas to seem to be drying out since I resealed the rails and ran a fan heater in the bathroom area for 2 weeks.

 

Thanks in anticipation for any advice.

 

Regards

 

Tim

44763[/snapback]

 

Sorry about the last post,false start.

 

It sounds as though you have a major problem Tim.

I have had similar problems with two vans in the past,the first was an avondale,the high level windows on the back with ineffective latching mechanisms was found to be the culprit.

However. The repair was as dealer A suggested,but I did the repair myself(I am a carpenter with full machine shop facilities and have built three camper vans, one being coachbuilt)I had difficulty locating matching internal panels,but the rotten frame replacement was easy for me. If memory serves me corectly the repair cost me about £200 + my labour, a good week and a halfs worth,+ machine shop+ free preseservative,foam,screws etc.

 

Then I traded it!

 

My opinion . I hate to say it, dealer A or. get rid.

 

For the record,my other leak was high level nearside rear,could`nt find the cause (at home) then one day on site spotted the problem. Awning was pulling the rail off it`s bed, just a couple of mm and in one spot. Fixed it. Peeled a small area of the internal vynyl from the affected area and dried the base ply with a hair dryer,restuck the vynyl. job done.

 

Got rid and bought a german. Sad "en it"

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with reference to question number 3, a dehumidifier never seems to be effective on materials around it unless its been running constantly for 48 hours.

 

Good points on the frosty weather and no humidity - I remember now, my machine hardly picked up any moisture when it got cold. We still get damp winters though.

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