Dampish thoughts and question.

[Sam Vimes]

I had my service on the caravan done yesterday. The damp check indicated some raised levels around the nearside wheel arch - 20 to 25%.

They sent a picture (attached) of the underside that shows the floor is not quite tight up against the side. They suggested some sealant which I will do but I also have some of this decking tape and thought maybe that would also help.

https://www.amazon.co.uk/dp/B0DW4JLL7L?th=1

Also it occured to me that this may be a temporary rise in the level as the journey to the workshop was in heavy rain and lots of surface water that is always more on the near side.

Also has anyone used a fan heater to dry things out in a small area like the wheel arch which is in a cupboard. Where else would you keep it

Comments welcome.

 

[otherclive]

In May 2021 we had a very wet journey to North York Moors and the weather did not improve over the subsequent 2 weeks. We had been discussing selling the caravan, but that holiday decided us. So in getting the caravan ready I had our AWS tech carry out a full damp test some three weeks later. The overall levels were okay but had been better, and nearside wheelarch area was around 17%. The tech said it’s okay given the recent wet usage and it should dry out. It did and the AWS gave me a FOC repeat survey around the wheel arch and adjacent flooring together with another report.

Given that mine was incurred in May and tested in June/July I let it dry naturally. Yours might benefit by some local heat. The tape can’t do any harm, and could you plug the gap using electricians putty which is waterproof and stays flexible.

 

[Sam Vimes]

Thanks OC....

I was thinking of sealant but you mention electricians putty which I don't use but do have Plumbers Putty which sounds the same and may be easier to push into the gap than sealant.

I've yet to get under it. Was due to collect today but the incoming storm is not the best weather to tow in so put collection off until Monday.

 

[otherclive]

Thanks OC....

I was thinking of sealant but you mention electricians putty which I don't use but do have Plumbers Putty which sounds the same and may be easier to push into the gap than sealant.

I've yet to get under it. Was due to collect today but the incoming storm is not the best weather to tow in so put collection off until Monday.

I’d favour Electricians putty as from experience it weathers very well. Not sure plumbers mate would be as good. I used Electrician putty for waterproofing the terminal contacts on my movers. Never had any water ingress issues again. Readily available on line. .

 

[Sam Vimes]

I'll check out Electricians Putty but I've used the Plumbers stuff many times for things like this - not caravans though - and its always worked well. Somewhat different I've found to Plumbers Mate as it never goes hard, remains flexible and can be removed easilyish.

 

[otherclive]

I'll check out Electricians Putty but I've used the Plumbers stuff many times for things like this - not caravans though - and its always worked well. Somewhat different I've found to Plumbers Mate as it never goes hard, remains flexible and can be removed easilyish.

Here’s what I purchased.

Electrical Weatherproof Sealing Compound, Individual 100g sticks Term Tech S391 | eBay UK

Chemical resistance Resistant to oils, detergents, grease, water, caustic sodas, petrol, alcohols, mild acids. • General purpose sealing.

www.ebay.co.uk

 

[Sam Vimes]

👍👍👍

 

[ProfJohnL]

The figures you have quoted are not massively raised and considering the change in weather with cooler conditions some surfaces may well be getting rid of excess moisture due to dropping temperatures. I would suggest monitor the situation and is its consistently higher over a month or so then you should be looking for a smoking gun.

As for using a fan heater, what that will do is to raise the temperature of the wood in the hot air flow, which will evaporate more moisture and dry the wood, but when you turn the heater off and the wood cools down, it will still be abnormally drier and it will seek moisture from the air until the vapour temperature pressures are equalised.

As ever good fresh air ventilation is by far the best simplest and cheapest solution.

 

[Dustydog]

How was this joint originally sealed at the factory?

If the joint for whatever reason has opened up and the damp readings on the “inside” are abnormal then some form of sealing may be required.

I’d use a caravan manufacturer approved sealant like Soudal RV 61 or Sikaflex 522.

 

[IanB1485]

I see a lot of caravan floors from underneath and the manufacturers use a sealing tape to cover joints . its not duct tape but is similar . I found the electricians sealant a little hard when cold , plumbers mate is quite soft and will 'sag' over time unless supported ( its great for picking up screws in inaccessible places)I 'd go with soudal fix all or equivalent and then tape with gaffer(duct/duck) tape

 

[Ukdave2002]

I have used this sealant effectively , where a flexible seal is required, it worked well and has lasted:

https://www.screwfix.com/p/sika-sikaflex-ebt-hybrid-sealant-adhesive-black-300ml/79299?tc=MA8

 

[Sam Vimes]

Thanks for all the replies.

Silcone sealant would seem like a good idea but I've found that its not always easy to 'squirt' into small gaps - although I do have some disposable syringes that may help.

Either way, whatever I use to fill the gap will also be covered with a suitable tape.

 

[Sam Vimes]

The figures you have quoted are not massively raised and considering the change in weather with cooler conditions some surfaces may well be getting rid of excess moisture due to dropping temperatures. I would suggest monitor the situation and is its consistently higher over a month or so then you should be looking for a smoking gun.

As for using a fan heater, what that will do is to raise the temperature of the wood in the hot air flow, which will evaporate more moisture and dry the wood, but when you turn the heater off and the wood cools down, it will still be abnormally drier and it will seek moisture from the air until the vapour temperature pressures are equalised.

As ever good fresh air ventilation is by far the best simplest and cheapest solution.

Yes, the figures are not that high but I'd like to bring them down.

As for the wood attracting moisture from the air I'm not so sure. We store our winter supply of kiln dried hardwood logs outside next to the caravan. RH here can be as high as 99% but I checked the moisture content just a couple of days ago and it was still at the 18% level. They've been there since last winter.

Ventilation is always good but it doesn't remove existing damp.

 

[birdman101]

When in B&Q ,Wickes etc stick your damp meter in a piece of Kiln Dried timber and 17% reading is not unusual

 

[otherclive]

Wonder what naturally dried timber goes down to. My son’s house is in its own woodland and surrounded by other woodlands where the owner is happy for villagers to take the fallings. So after a good storm off they go with chainsaws at the ready. He stores his logs in a three sided barn and under the front south facing balconies plus other little lean too’s. His general rule is not to burn it for two years and when he recently had the chimney swept there wasn’t much soot came out.

 

[Sam Vimes]

Supposedly there's a legal limit of 20% for Ready To Burn logs but this may vary with quantity - larger quantities maybe allowed higher values on the basis that some of them will be dried before use I guess.

We buy in kiln dried hardwood at 18%. One year we tried Semi-Seasoned Larch which we needed to keep for 4 months to get it to the 18% level but I can't remember what it was when we got it. Either way it wasn't very good in our fire compared with the Hardwood Logs. We did get a discount because of that.

We also have some small logs from our own trees and keep them in the outside store for a year. They come in at 16% - again not sure what they started out at.

I clean the chimney every year and there's virtually nothing in it. Little ash in the pan as well - what ever there is goes onto the garden.

 

[otherclive]

My son’s wood burner was installed in 2022 and meets current regulatory requirements in so far as its design and installation is concerned, but they don’t live in a specific smoke control area. He only burns hardwood and it’s two years maturing outdoors but in dry enclosures. Must admit when we were there two weeks ago when he lit it at night it was lovely with a glass of wine. Very relaxing.

 

[RogerL]

My son’s wood burner was installed in 2022 and meets current regulatory requirements in so far as its design and installation is concerned, but they don’t live in a specific smoke control area. He only burns hardwood and it’s two years maturing outdoors but in dry enclosures. Must admit when we were there two weeks ago when he lit it at night it was lovely with a glass of wine. Very relaxing.

My neighbour has a wood burner - he collects casualty wood locally but avoids certain tree species which can produce more contaminants.

 

[IanB1485]

As for the wood attracting moisture from the air I'm not so sure

wood is porous( see microscopic view of wood) and will absorb and expel water vapour as the external humidity rises and falls( unless treated with a sealant such as ronseal wood preserver or painted) .As you say artificially dried wood will give a low reading. Wood will dry out naturally if kept undercover but it takes ages, Also due to the differences in the structure of different woods the dry percentage varies ( for one of my damp meters I have a conversion chart for all the different varieties of wood).

 

[DaveA1]

My fire is slightly to small for my two bed bungalow, in fact it is a narrow boat fire. I normally burn dried hardwood, This year I have some cherry and apple, two years drying./seasoning. Burn fast, very little soot in chimney . open all the doors warms whole bungalow.

 

[Sam Vimes]

I went under the van today to look at the problem in the photo and try and fix it. The gap is between the side walls and the floor. Its only about 1mm wide at the bottom but doesn't appear to go all the way through. No sign of movement so I suggest its just another quality installation :-(

The gap was too small to squeeze any meaningful quantity of sealant in so I just used my 50mm wide deck joist tape which is supposed to be waterproof - its certainly stood up well on my deck. It's bridged the gap very well and I'll see over winter if it stays stuck on. Certainly stuck to my fingers well.

Of course while underneath I took a look around and it just confirmed to me what a shoddy design and build caravans are - and I don't suppose its just mine. String and sealing wax came to mind but I suspect that would be an improvement.

I noticed a gap that had opened up slightly on one of the kitchen side panels were the oven/hob is. It butts up to another panel. No gap at the bottom - 2mm gap at the top. Worktop coming away ever so slightly from the wall but you can push it back. I got my Boroscope out and stuck it up between the oven and the panel to see if I could spot the problem. There's a piece of wood that bridges the gap and is supposed to be screwed to both panels to hold them tight together. The screws at the top were not screwed up very much so weren't actually doing anything. I managed to get my arm up there and screw them home.

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