Roof rot

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  • #13879
    george rhyneer
    Participant

    Just so everyone knows. I’m doing a 10 yr overhaul on boat including lengthening it but was checking for rot in the pilot house roof and salon. In the pilot house every single hole that was drilled for antennas, search lights and radar leaks. 520o works for a few ya ears only. After cutting out the top skin I have totally rotten plywood and a 1/4,inch of standing water in the plastic honeycomb core they used in the pilot house.

    #13880
    Tom Easterbrook
    Participant

    George,

    Sorry to hear that you have so much of a problem. All sealants do not last forever. However, unless you are looking for a very strong adhesive as well as sealant (then 5200 may be OK), I would not use 5200 for sealing purposes on our Tugs. I recommend Sikaflex 291 or 295 UV where the sealant will see lots of sun (like the Pilothouse to salon roof joint). Sikaflex is much easier to remove (than 5200) when it comes time to rebed all of these “penetrations” you are describing, which should be redone regularly (5-8 years) depending on if the sealant is subject to any “movement” (flexing) or not.

    I recommend trying to minimize  “roof” penetrations, as they could (and will if not maintained) leak. Also, when attaching anything to railings (like fenders, etc.) always attach them at the base of a stanchion (down low – deck or roof level) as opposed to on the horizontal railing where the strain could greatly increase any “flexing” which will eventually lead to leaks at the base where screws penetrate the roof or deck. If owners do not ensure this maintenance rebedding, is done regularly, they can expect to experience what you have found (to some extent; more or less).

    I can speak from experience, as when I purchased my NT, the surveyor found wet coring in the cockpit overhang coming from a leaking fitting. The repair required rebedding of all upper deck penetrations, removal of the lower layer of fibreglass, removal of the wet wood core, and adding new core, filling in any voids with epoxy, and reglassing and finishing the bottom “skin”, at a cost of over $7,000 (and the wet area was only approx. 9 square feet). To do well, this type of work requires skills and experience that I would suggest the average boater does not possess, and to hire a “pro” is expensive, possibly involving a long wait.

    Don’t put it off…….Rebed.

    #13881
    Tom Easterbrook
    Participant

    One other product that could be used to “rebed” most of the items George is discussing is a product called “Butyl Tape”, as long as it is a quality brand. There are some cheap versions out there, so be careful.

    #13884
    george rhyneer
    Participant

    I hear you all. I think the only real fix it to mount a “dry box” on the roof which has all the wires running into it and then down a hawser pipe inside that’s a few inches above the deck.  All of my holes are the factory made ones that are under the nave lights and radar and other antenna, etc.   Certainly everyone should look at those sites regularly.  It was not obvious with taping on the roof to hear the “thunk” of wetness but with taking off the ceiling in the pilot house the ply was damp and black mold was forming so I knew something was up.

    thanks for input. trying to get pics up loaded but having difficulty.  G

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