Winter Project #1: Ceiling repair

[CharlieO.]

My first project to undertake is removing the headliner and replacing the core in the ceilings of both staterooms and making sure all my backer blocks are up to their task. Also pulling my forward hatch to rebed and reseal the hatch itself.

I am starting with the forward stateroom (v-berth) because a P.O. already tried doing a bit of repair from water leaking. They removed the core from a section and replaced it with plywood and added a small bracket to the crossmember framing. I will be removing all that to repair.

It did leak a bit on hard rains and one of the backer blocks for the exterior handrail was nonexistent leaving the handrail not as secure as it should be. Similar situation on the rear cabin; not super secure handhold/rails and one the stantions that one of the mast cables secure to pulled a bit loose. I'm guessing the wooden backer blocks are not good there either. We plan to use the mast and boom for lifting our dinghy to the aft cabin roof and I want to be sure that everything is secure and able to take the load.

My plan is to
1. Remove everything on the ceilings working from inside the boat. Take down headliner and core all the way to the outer fiberglass skin.

2. Plan to address all the backing blocks for the handrails and mast stantions, rebed all deck fittings, add blocking/strength to where I plan to mount my dingy cradle on the aft roof.

3. Recore or something? to add structure/strength back to the decks.

4. New headliner.

There will probably be a little project creep such us updating the wiring in the ceiling and moving/adding ceiling lights.

Luckily everything I've opened up so far has not presented any unusual surprises.

I am open to any tips from anyone that has done similar work. Not sure what I should recore with?

These pictures are all from the forward stateroom.

 

[RT Firefly]

Greetings,
Mr. CO. We did a similar repair to our 1974 Marine trader DC many, many years ago. From memory (poor) we approached the problem from the outside on the horizontal sections
Strip off the FG and old coring down to the deck beams (there was NO inner FG layer). Lay down and epoxy multiple layers of 1/4" (I think) marine ply to appropriate thickness, staggering seams, remove and rebuild deck light (hatch similar to yours-easy to do as it is a one piece unit).
Multiple layers of new FG using epoxy. Reinstall hatch as one unit. We did BOTH fore and aft decks AND a section of fly bridge.
I think the vertical sides of the forward cabin were 5/8" ply originally and not all of it was bad. I carefully removed the rotted sections from the inside and applied multiple layers of FG to build up to existing 5/8" ply.
Does that make any sense, at all?

 

[CharlieO.]

RT- so when you stripped the fiberglass and core working from the outside you just had a big opening prior to rebuilding?

The starboard side ceiling still has the inner fiberglass layer intact, I stopped demo on that side once I got to the inner fiberglass. I do plan to remove that side too because although it doesn't feel soft, it definitely is not all still laminated/epoxied together.

I was thinking of doing multiple layers of thin ply put into place with thickened epoxy with pressure from underneath to hold it in place till it all cures. Probably epoxy coat all sides and edges of ply before installing.

 

[Gdavid]

I would start researching the vacuum bag fiberglass technique if I were you, it sounds like a lot of work and materials, and it is, but it really is the best and cleanest approach to making a fiberglass repair from below.

 

[Datenight]

CharlieO,

I did extensive re coring on the green boat around 2000. Did it much the same way you plan to. Stripped everything back from the inside to the outer skin and fitted new plywood core. The plywood was shaped if needed to fit and pre saturated in West System epoxy. At least three layers of glass over new core.

Any place that would have a penetration from the exterior was over drilled and filled with epoxy to prevent future rot problems. Synthetic core may be a better choice now but the plywood was easy to work with and the way I installed it will never be a problem.

Wish I knew what happened to all the pictures I took...

Rob

 

[CharlieO.]

Datenight,
You put three layers of fiberglass/matting on the inside after replacing the core? Then new headliner over that?

 

[RT Firefly]

Greetings,
Mr. CO. Yep. BIG hole. The deck over the forward cabin, for example:


The outer layer of FG was only one ply thick so trying to layer/force material in the spaces between the beams from inside would probably have resulted in an uneven outer profile, so...


Stripped the outer layer off over the outer edge to the teak 1/2 round molding on the sides (after removing the molding). The meeting of the new and old outer surfaces would occur UNDER that 1/2 round and be hidden. Remove core material to deck beams.

Some of the beams were "iffy" at the ends and interfaces with other beams and they were reinforced/scarfed or replaced. Ply (in multiple staggered layers) was laid right to the edge of the main outer beams and profiled to a suitable radius right before application of the outer skin which was wrapped around the edges/corners and met the vertical skin under the side teak molding. A bit of fiddling under the forward windows but that area was reinforced, as well before cladding.

Skylight, as I mentioned, was repaired and refinished OFF the boat and simply slipped and screwed into the square opening in the newly clad deck with 4200 (I think).

Thickened epoxy was used throughout for sealing, layering and laminating. The vertical sides were partially rotted so I reamed out the rot (leaving the outer skin intact and built up the new thickness to the remaining old thickness with cloth and resin.



"I was thinking of doing multiple layers of thin ply put into place with thickened epoxy with pressure from underneath to hold it in place till it all cures."

A few problems with that IMO.
1) It will be difficult to get new material in the space between the existing skin and beams.

2) You will be working against gravity with the resultant sagging and dripping.
By stripping the whole works, once you get the initial base layer of ply onto the beams you can slop that epoxy on and not worry about damage to anything inside the v-berth AND add curing weights without having to jack anything up from the inside.

That was MY approach since the outer layer was VERY thin (one ply) and easily replaced. If YOUR outer skin is substantially thicker and you want to save it, you're on your own...sorry.
Perhaps you can remove the whole outer skin in one piece, re-core and glue it back down????

 

[CharlieO.]

RT - Got it thanks. I will finish the deconstruction this weekend and evaluate further. I agree it probably would be much easier to take the skin off and rebuild from the top. Not sure I got it in me to skin her though. Don't know if I could stand the sight and I'd have to ban my girlfriend from the boatyard until she was decent again....

Oh, and my woodworking skills and ability to work in uncomfortable and messy positions way eclipses my fiberglass skills.

 

[RT Firefly]

Greetings,
Mr. CO. Don't shortchange your skillset. Working with FG cloth and epoxy resin is pretty straight forward. IF you screw up, that's what they made sanders for.
I would VERY strongly suggest you use an epoxy system that does NOT form that Amine? layer of wax on curing. Removing that wax is just another added step in the process that is completely unnecessary. West System (WS) IS good but it forms that waxy layer and MUST be cleaned off well for added layer bonding. I've used MAS (Marine Adhesive System) with success and I'm pretty sure it's cheaper. I've used WS thickeners with the MAS with no seeming ill effects.
Also make sure you use epoxy compatible cloth and mat. There are 2 types. One for polyester and one for epoxy.

 

[Datenight]

Datenight,
You put three layers of fiberglass/matting on the inside after replacing the core? Then new headliner over that?

Yes.

Rob

 

[Comodave]

If you are doing it from the inside or bottom, I agree on getting vacuum bagging equipment and doing it that way. Whatever core you use will probably last the life of the boat at this point if you are careful in attaching things to the deck. Marinehowto.com has an excellent article on bedding things to cored decks. I would definitely use a layer(s) of fiberglass on the bottom for the I beam effect. If you are using epoxy don’t use mat, Chopped Strand Mat, as it is “glued together” with something that epoxy doesn’t break down so it doesn’t wet out easily. Unlike the layer of mat in 1708 which is stitched together so epoxy will wet it out properly. 1708 is nice to use as it is 2 layers of glass on a bias and a layer of mat all stitched together so the thickness builds up quicker and it is very strong. I use a right angle drill with a Roloc attachment for grinding the old glass to prep for new glass or core. It can quickly grind off all the old crap with a 40 or 50 grit disk. The right angle drill allows you a lot of control over the grinding.

 

[PM]

Either way you approach it, it's a big job, and a big mess.

Good Luck with it.

pete

 

[CharlieO.]

What type of wood would be recommended to use to rebuild the framing. It doesn't seem like Home Depot pine lumber would be the most suitable. Plywood type? I do plan on resin coating everything prior to assembly.

Thanks

 

[jleonard]

I rebuilt the gunnels on my old Mainship from underneath using polyester resin, 1 1/2 ounce mat, 5/8 exterior plywood and bondo.
Ground out the old core and did a layer of resin and mat attached to the underside of the outer skin.
Then cut and pre fitted the plywood that was coated in polyester resin thinned 25% with acetone (to allow the resin to penetrate the wood).
I attached the plywood to the underside with Bondo (compatible with polyester and cures quickly.)
Then 3 layers of mat and resin. and it was done.
Ruined a couple of sweatshirts and hats, but all in all was really no more difficult that working from above, just a little messier.

 

[alormaria]

You need to get that puppy under shrinkwrap before the snow flies. Not only does it make working on it more pleasurable but it saves a lot of wear and tear on your decks and other woodwork. Tie down the aft handrail in the open position for your door.

 

[CharlieO.]

You need to get that puppy under shrinkwrap before the snow flies. Not only does it make working on it more pleasurable but it saves a lot of wear and tear on your decks and other woodwork. Tie down the aft handrail in the open position for your door.

Yes, sir.... she's all wrapped up for the season. although I have my zipper door on the starboard side just outside the helm door.