Removing motorhome sealant.

[TheMitchells]

Not building related, but i am hoping for advice from the forum on how to remove sealant on motorhome joints.  

 

We have just discovered that our 17 year old motorhome has quite bad damp, within the walls, that really needs sorting.  However, this involves removing all internal units, cutting away the interior walls, removing the damp insulation inside the walls, and then replacing everything!  We have been told it will cost over £10k as it will take 4 weeks.  About 60% of that is labour.  Our motorhome is only worth about £15k yet it is perfect for us and we did not want to replace it for another few years. Internally, there appears to be no mould within the living quarters. it all seems to be within the walls, and so far, we have never smelt or seen mould. Financially, it is just not worth us having the work done.

It is highly likely that water has entered via the external sealant, now 17 years old.  It is all very dry and cracked.  So our thoughts are to just remove and reseal the external joints with Sikaflex 522 ourselves.  And keep it going till we can afford to replace it in a few years or until the damp starts to show in the living area.  

 

Any advice on the best way of removing as much old sealant as i can before I reseal with new?  I've done quite a bit of sealant applications in the past but not sure about how best to remove the old stuff.  Thanks.

[SteamyTea]

25 minutes ago, TheMitchells said:

 

Any advice on the best way of removing as much old sealant as i can before I reseal with new

There will be a solvent that works, but unless you know which adhesive was used, it will be trial and error.

Start with the easy solvents.

White Spirit, Methylated Spirit, Acetone, gasoline and WD40.

Don't convince yourself that with a bit of solvent and a huge amount of elbow grease that it is working. A solvent should make it dead easy to remove.

If none of them work, then it is a case of internet shopping for things like Dichloromethane, my favourite and Xylene (my least favourite), or even Toluene. 

I think it was @Onoff that found a cleaner in Lidl that seemed to remove most things, so maybe trip there on Thursday.

Edited 2 hours ago by SteamyTea

[saveasteading]

 

12 minutes ago, SteamyTea said:

my favourite

You forgot Snibbo.

[TheMitchells]

I'll give these a try.  I do recall WD40 being good for sealant removal.  😊 I guess it may be a case of trial and error and a steady hand with a sharp chisel.

[saveasteading]

I've got some old sealant that I should have thrown away because it was never much good. I will see if solvents are mentioned.

[ProDave]

If you can't see or smell damp or mould, what makes you think the structure has got wet?

 

A well designed caravan / motorhome will be built with all joints lapped the correct way so water does not enter and the sealant is for good measure only.  The one exception to this was an ABI we had in the 90's that when investigating damp (it really was damp and showing) I found to my horror and disbelief the wall to roof joint was lapped the wrong way so it was only the sealant stopping water entering.

 

If there really is water getting in, I am not sure I would be ripping it all apart from the inside, it is the external joints that need investigating and re sealing, mostly roof to walls, and wall external corners.

[Onoff]

56 minutes ago, SteamyTea said:

I think it was @Onoff that found a cleaner in Lidl that seemed to remove most things, so maybe trip there on Thursday.

 

Screwfix No Nonsense remover worked for me.

[MikeSharp01]

I am aware that some manufacturers have had issues with condensation in the walls of their machines it may just be that. Why not look at a dry the panels out solution - drill a pluggable hole, connect a pipe to the hole and a tub of silica gel and see how much moisture you can draw out that way. You can get Silica Gel in volume: https://www.amazon.co.uk/Quart-Replacement-Desiccant-Indicating-Silica/dp/B013L31PQ0 that one is indicating - it changes colour as it gets wet and is likely to be toxic if swallowed - IIRC normal, non indicating, silica gel is harmless though