# camper mastic reseal (hindsight is 20/20)



## nafricasurfer (Jan 22, 2014)

Hi all -

We have just completed resealing the mastic seams along the alcove of our motorhome. We want to pass on what we learned and I hope this will save others some time.

It was a VERY big job. Don't do it. Replace the screws first & see if that fixes it.

Looking back on this I now realize that when you have a small to medium leak, tearing off the rails and old mastic IS PROBABLY NOT NECESSARY.

When removing old mastic from my motorhome I could see that it was looking very gooey and sticky. Most probably it was keeping the water away from the aluminum seams.

The one part of the roof that did not look good were the screws holding down the aluminum rails (which were pressing down on rubber which was holding down mastic to cover the aluminum seams). These were rusted badly so that it was near impossible to get them out. 

These screw holes were probably where the water was coming in. As the screw rusts, it gets smaller. After a while the rain can go into the screw holes. 


Trust me on this one... Replacing screws is much easier than replacing mastic.

Changing the mastic is very involved and time consuming. It takes days, and it must be done under cover. Scraping away gooey old mastic, white & meths spirits. You need someone else to help remove and return the rails. You need many tools. You need lots of rags & kitchen roll.

Changing screws is easy. You can change screws as you have time, one at a time. To change a screw:

1. Remove it. (may need to use a Dremel to cut a small channel into the screw head. Or you can use a drill bit. Or maybe a file.) 
2. Squirt mastic or sikaflex it into the hole.
3. Put in a new stainless steel screw #6 (1 inch long) screw. (get 100 from screwfix for about 5 pounds) You may want to use a Pan head screw so that the screw rests nicely on the rail. 
4. Get some #8 screws if you find a screw that just turns & turns. If a #8 just turns & turns, then maybe you have some rotten wood in there. In that case the repair could be more involved. Probably worth it to bring it to a pro to be fixed. Or maybe you can inject some wood rot fixer (epoxy stuff) but I am getting out of my experience with it now.



Cheers!
Matt


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## Mrplodd (Mar 4, 2008)

Thanks for taking the time to share your valuable experience, I am sure many will find it very useful (hopefully NOT me :wink: )


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## VanFlair (Nov 21, 2009)

Hi Matt

If you have any screws that are not pulling up tight you can take a couple of cocktail stick and I dip them in PVA glue then add a couple of lengths into the hole, just poke them in and snap off, then insert the screw.

If you use epoxy it is worth putting a bit of wax polish onto the crew thread and then you stand a chance of getting it out again if/when you want to.

I did awning rails on our caravan some years ago and I reckon you are right that its more than likely the screw holes causing damp problems.

Martin


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## stevegos (Jun 23, 2013)

any chance of posting a few photos of what you have done?

I have a seal along the top of the MH which I think looks suspect for a future leak and was thinking of sealing it.

Steve


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## nafricasurfer (Jan 22, 2014)

Hi all -

We will post photos. Just now too busy to do so as we are under the roof of one kind man up here in North Ireland. We must work fast as he would like his shed back. 

Steve... Can you see the screws up there? How old do they look? My advice, after doing this, would be to first just get the old screws out.

I just did this down the side of my 23 foot long 1997 euramobil. The screws were rusted something terrible. Under the guidance of this kind man, he showed me how to give the screw head a whack to break the aluminum to steel bond. Then with a 1mm cutting disc, cut a small notch in the top of what is remaining on the screw head. After that the screw just comes right off.

Matt


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## nicholsong (May 26, 2009)

Matt 

I have just replied on your other thread about mastic/Sikaflex before realising that you are running two threads for different aspects of the same job.

Are you saying that the screws have actually rusted, as in they are ferrous, or have they corroded, as in alloy? Either way the converter should be using S/S in that environment.

What MH do you have? What age? Are the converters and/or dealers still in existence?

I will await you answers before I make a mistake of overstepping the mark.

Geoff


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## nafricasurfer (Jan 22, 2014)

Hi Geoff -

It\'s a Euramobil 1997. The mastic they used is some very black stuff. More viscous and hard to clean off than the W4 tape, but perhaps that is because of its age. 

The screws had rusted. A couple of them their heads just popped off with the whack, but most had to be cut with a disc and then slowly removed with a flathead screwdriver.

I\'m not sure what you mean by \"the converter should be using S/S\" What is S/S?

Looking forward to your response.

Thank you-
Matt


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## nicholsong (May 26, 2009)

nafricasurfer said:


> Hi Geoff -
> 
> It\'s a Euramobil 1997. The mastic they used is some very black stuff. More viscous and hard to clean off than the W4 tape, but perhaps that is because of its age.
> 
> ...


Apologies for late reply - I have just got back from a trip to UK for a funeral.

S/S is stainless steel.

One would never build a boat with ferrous fixings (nor in my opinion alloy ones, which are subject to salt-water and electrolytic corrosion) and I think that converters who use non-stainless are at fault, because even if they are originally protected with a mastic seal, that will harden over time and with the constant vibration and thermal stresses, to which motorhome constructions are submitted, the bond is likely to be broken and the ferrous fixings subject to water/damp ingress and rusting.

I would be inclined to approach Euromobil, assuming the screws were their work and not that of a subsequent company doing other work, asking them to contribute to repairs on the basis that the fixings were not 'fit for purpose' - a legal concept under the Sale of Goods' legislation.

Geoff


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## Carl_n_Flo (May 10, 2005)

If the van is a 97 year as the poster suggested, then I doubt you would get any joy from Euramobil about contributing to ANY costs relating to this.

It is nearly 20 years old!! 

Sometimes we just have to accept that nothing lasts for ever - even our beloved motorhomes..........


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