What sealant do I need?

[StClements]

Hello! I recently bought an Avondale Avocet, I think 2003, it had been sitting in a field for 4 years but is in great condition. I just want to reseal the top seams on the roof, they're a bit dirty and have some organic build up, not quite moss. I'm going to literally scrape it out gently with a toothpick! then clean, and reseal... but what is a good sealant for this specific job? Thank you

 

[IanB1485]

You may not need any , if you slice out the excess sealant with a paint scraper/pallet knife(don't use a sharp knife like a stanley) then you may find the sealant underneath is unbroken and clean.I have seen lots of caravans where there is excessive sealant around various external fittings such as windows, locker frames e.t.c and its this excess sealant which over time accumulates debris and turns black. Most caravan manufacturers use a non setting mastic to seal external fittings its called W4 and comes in various widths and colours . also you can get it in a cartridge as a fluid. For small repairs I use a setting adhesive sealant (not bath silicone sealant) such as Soudal fix all or sikaflex 522 . I use IPA to help smooth it and remove excess whilst still unset.

 

[StClements]

Interesting! After we bought it, we had it serviced and the guys went round it with a dampometer and it had a few areas of mild concern, and as I have been cleaning it up this week I have found a couple of areas of bubbling behind the wall covering, well, not even bubbling, it's almost like there is small pieces of grit behind the top layer of wall? I'm assuming this is because water has got in it's it's years of neglect. We will cut out any bad bits and replace but I just wanted to seal any gaps I find before that as we will be doing any repairs as and when we have the time and money! Am I doing the right thing, in the right order?!

 

[IanB1485]

The 'grit' is mould spores bursting out of the plywood , the vinyl wallcovering will stop them entering the atmosphere and if you seal the leaks the water content will drop and the spores will hibernate . Certainly resealing the awning rails to the roof/walls is the best place to start. If you have an aluminium awning rail then sometimes its the securing screws which leak . To access them you will have to remove the herzim cover strip then look for signs of rusty screws, remove and replace but inject some sealant into the hole first. To refit the Herzim strip softening with a hot air gun ( don't over do it) will help. I clean out the gap between the awning rail and top of the caravan with a paint scraper then clean with IPA to degrease and dewater the surfaces and apply the Soudal fix all sealant and smooth it out whilst its still tacky.

 

[toad a caravan]

I resealed all my aluminium rails,I have put method and images on the"Vintage" section.

 

[toad a caravan]

Both these sealers are bitumastic.I replaced all the Herzim with new,it went in no problem,, Always allow extra overhang to allow it to shrink back before a final trim