Keeping The Rain At Bay

I haven't put anything up for a while. Our daughter has been seriously ill, which entailed a month long hospital stay. Posting hasn't been a huge priority.
With things getting better and recovery under way, we have finally had some time to relax and think about a few maintenance jobs.
We have had a minor leak for a while, so prioritised with some sealing of some problematic roof joints. 

I think we've nailed the perfect solution to roof joints; a maintenance issue that apparently many caravan owners can't get the hang of. I've seen everything from liquid nails to bathroom silicone spread over roof joints on caravan, with various degrees of ineffectiveness.
In my opinion, the old school solution is the best. Joints overlap. No matter what you spread over them, it's still all about sealing under them. As far as that job goes, butyl rubber mastic is the way to go.
Clear out whatever exists under the joint as far back as you can, fill that gap with butyl rubber using a silicone / calking gun and smooth it down flat.
It's pretty fail safe, but occasionally the most tiny air bubble can result in a tiny and persistent leak that's an absolute bugger to find!
Enter my new discovery! Sika, Self Levelling, Polyurethane sealant. At 20 bucks a tube, cheap it ain't. However, it's as close as damn it to the perfect solution. Not only is the butyl in your joints  made airtight, but also protected from the effects of the sun, for years.
After the butyl has set, simply apply a line along each side of the joint and spread it over the line of the joint with a paint scraper, like icing a cake. The sealant will not only find it's own level forming a wide strip over the joint, it will also find it's own way into any pinhead size holes or air bubbles that might otherwise result in a leak. It's flexible after having set and reflects UV. It's brilliant!
Our recent problem was around a hatch. I found it particularly useful in that application, where the relief was varied and the sealant found its own way into problematic corners.
I estimate that 2 tubes of butyl at around $25 and 3 tubes of the self levelling sealant, should re-seal all roof joints on a 20ft van. That's pretty good for around $110.