Deck water intrusion

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Egregious

Guru
Joined
Feb 5, 2010
Messages
555
Location
USA
Vessel Name
Polly P.
Vessel Make
Monk 36
We were in our boat this last week during a large downpour and water began to drip into the master cabin. I immediately removed the headliner to find the cause of the leak. I think the source turns out to be deck screws drilled too deep which penetrated the roof.

The question is, how to close the leaks? Do I need to dry out the affected areas or just fill them in and re-bed the affected areas?

Attached photos show the underside and deck side of the source of the leaks, after I removed the screws.

I used common household caulk to reseal the holes until I can repair this in a more permanant way.

Any advice would be greatly appreciated.

Woody
 

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For filling holes epoxy like Git Rot , which contains alcohol (which chases the water) is recommended.

Then some moisture can be in the repair with out harm.

Relocate the item , and perhaps use a pad outside under the item to raise the seal area.

FF
 
since you already have the headliner off Ii would replace the screws with bolts, nuts and a backing plate. For a couple of years I have been using butyl rubber tape to bed items like you show in the pics. I find it works very well, just pick up any trimmings or they'll get tracked around the deck.I can't tell if there is wood inside the deck there if so I'd do the usual clean out, epoxy fill and redrill steps first.
Steve W.
 
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since you already have the headliner off Ii would replace the screws with bolts, nuts and a backing plate. For a couple of years I have been using butyl rubber tape to bed items like you show in the pics. I find it works very well, just pick up any trimmings or they'll get tracked around the deck.I can't tell if there is wood inside the deck there if so I'd do the usual clean out, epoxy fill and redrill steps first.
Steve W.


I agree, since you have head liner off, then repair with bolt nut and backing plate in the in side. I would use 3M 5200 caulking under around and in the bolt hole. 3M 5200 before it dries cleans up with paint thinner, so you can be a little messy. Since you have the head liner off might want to due the other as well.

Next time if you do not want to take down the head liner, you can repair from the out side using epoxy with filler additive to fill the holes, and then re drill the correct size. I had to repair two rails this summer using epoxy, and 5200.
 
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Greetings,
Mr. E. The first questions that came to my mind were: How long has this been leaking and if any coring material was involved, how wet was it and was there any sign of rot?
If one assumes the worst (long existing leak and damaged core) I would do the following...
As Mr. Steve suggests, clean out damaged core and refill with epoxy BUT unlike others, I would NOT use nuts and bolts unless removal of the headliner is EASY when it is time to re-bed. IF you have the space perhaps a thick pad underneath the deck could reenforce the area while using longer screws.
Caulk? Read the thread Mr. CP offers.
 
Greetings,
Mr. E. The first questions that came to my mind were: How long has this been leaking and if any coring material was involved, how wet was it and was there any sign of rot?
If one assumes the worst (long existing leak and damaged core) I would do the following...
As Mr. Steve suggests, clean out damaged core and refill with epoxy BUT unlike others, I would NOT use nuts and bolts unless removal of the headliner is EASY when it is time to re-bed. IF you have the space perhaps a thick pad underneath the deck could reenforce the area while using longer screws.
Caulk? Read the thread Mr. CP offers.

Thanks for all the replies. First a little more information:

I had to remove the headliner to find the source of the leak. The water flowed in from a hole, and then down into the master berth via the headliner over the steps down from the main salon, and so it appeared at first that the water was coming in from above the deck there when in reality it was coming in from the flying bridge. Also, to be totally sure I poured a cup of water down the screw holes and my wife verified that water was flowing out below. By the look of the stain on the fiberglass above the headliner this has been leaking for some time, but just not severely enough for us to notice. I used calk just as a temporary measure until I can get back to the boat and do the job right. It looks like the next thing I do will be to re-bed everything that is screwed into the deck! Thank God I don't have Teak decks! :facepalm:
 
Is there any core involved?
From the pic it looks like it is just fiberglass. Those screws look short to go thru any core.
If there is any core you need to hollow out the area between the outside and the inside. to make a cavity. Using a bent nail or an allen wrench and a drill.
Then you would tape up the inside. Mix some epoxy with a little filler. Pour it into the hole so as to form a disk shaped plug between the inside and outside.
Then drill and bed as if it were a new area.

This method is considered by many to be the best way to fix this sort of leak. I originally read about in Wooden Boat Magazine.

SD
 
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