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I dont know about bitumen paint but I would think the underseal that you can buy for cars would be very similar and would do the same job.

                                                                            doug.

Halfords sell an underseal that goes on with a gun powered by a compressor.

It is an Underseal that contains Waxoil and and I used to use this on the chassis and wooden floor of my motorhomes.

It does a good job and 3 tins of the stuff did a large motorhome,

The Waxoil "creeps" and so if the underseal gets chipped by loose stones etc, the waxoil will heal the bared metal or wood.

Quote: Originally posted by oliver67 on 10/12/2009

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was wondering if bituman paint was good for the chassis on caravans which are not galvanized and for wood.I have been told good against rust any one used it for this purpose and had good results?

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Never paint the wood on your van with bitumen paint (I take it you mean the under side of the floor) It needs to breathe. You will be sealing in any moisture which will have the reverse effect......rot!  Give it a coat of proper wood preservative!

Mick

Quote: Originally posted by Mick + Linda on 10/12/2009

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Quote: Originally posted by oliver67 on 10/12/2009

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was wondering if bituman paint was good for the chassis on caravans which are not galvanized and for wood.I have been told good against rust any one used it for this purpose and had good results?

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Never paint the wood on your van with bitumen paint (I take it you mean the under side of the floor) It needs to breathe. You will be sealing in any moisture which will have the reverse effect......rot!  Give it a coat of proper wood preservative!

Mick

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I do not see any difference between the wood on the underside of a van and any other exterior wood.

If wood needed to breath, then why is most exterior wood painted?

I live between two boatyards and I can garuantee that there is not one single yacht in any of these yards that is painted with wood preservative!

Okay, they are not painted with bitumen paint either, but any wood is well sealed and I have sailed on yachts from these yards that are well over 100 years old.

Underseal, which is a very similar stuff is all well and good on new metal, but once it has got the slightest bit of corrosion or moisture, it seals it in allowing the metal to corrode away underneath, leaving a chassis shaped layer of underseal, but no metal underneath. I used to weld a lot of cars and have seen this happen many times.

Someone also raised the question here a long time ago about painting the wooden floor with underseal. The concensus was that the floor is already treated and any attempt to seal the floor up will stop the wood breathing and is likely to cause more problems than it prevents.

Therefore, I would say no to putting it on either chassis or floor. If you want to protect the chassis, you won't beat hammerite for rust protection. This contains zinc so as as close as you will get to having it galvanized without taking it off and getting it dipped.

Well I think horses for courses - underseal if the chassis is already clean but it won't stop existing rust, only cover it up. Hammerite would be more appropriate if the surface is not already clean

For timber  I would use a product designed for the purpose - bitumen is a building product. Not a timber treatment.

I think this talk about timber breathing is a load of rot personally. If it has moisture in it it has to dry out. When it is dry it can be sealed as per lobeydosser's boats. Once the tree is cut down it is dead and won't breath. However, it is my understanding that the floor of a caravan is treated for life and if it ain't broke don't fix it.

I've had two alleged gas fires 'catching fire' in motorhomes?!

On investigation in both cases under floor areas had been sprayed with underseal, it was this catching alight where it had coated the base of the fire.

Whatever you do then keep it away from this area