Re-caulking the Coachroof

As can be seen in this photo I took last summer just after I bought Wing, the caulking between her coachroof and deck is in a pretty sorry state.

It looks like there are two layers of caulking: a pink layer underneath, which appears to be the same adhesive substance as has been used to bed a lot of the hardware, and then a thinner black layer over the top.  I don't know if this was original or if the second layer was added at a later date because the first started leaking.  The caulking is definitely leaking now: it has pulled away from the coachroof in some places; from the deck in others; and the plywood of the deckhead is somewhat discoloured around the forward port coachroof corner post, indicating that there was water ingress sometime in the past.  The caulking was also not applied very neatly and looks ugly so it is time to re-do it.

I am using Teakdeck Systems SIS-440 for re-caulking on the recommendation of Tern Boatworks.  It is a one-part product that does not require priming and forms a rubber-like flexible seal.

I started by removing the old caulking; it came off quite easily with a box cutter, scraper, and a bit of 60 grit sandpaper.

A friend who is helping me out with Wing then taped around the deck and coachroof while I was working on other stuff.

 

The raised plugs visible in the lower to pictures are a whole other saga that will be the subject of another post. 

With the tape in place, and using a 1/2" thick block of wood as a spacer, I used a box cutter to remove the inner 1/2" of the tape from both the deck and the coachroof.

I wiped the exposed area with acetone to remove any oils, squeezed the SIS-440 into the gap in the tape using a caulking gun, and shaped the fillet using a wooden spatula with the end rounded to a 1/2" radius.  With that done I removed the tape leaving a nice clean fillet around the coachroof.

The SIS-440 was a bit sticky and messy to work with but it went on quite well and the end result looks pretty good.  Everything else seems to be in good condition so hopefully this is all it will take to stop the water ingress from around the coachroof.