houseboat roof repair replace help

Discussion in 'Materials' started by soloblazer, Mar 25, 2013.

  1. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You have a few ways to go, but putting good over bad is never going to have a reasonable outcome. It's a bit like painting over rust. It's be pretty for a while, but eventually the prettiness will not hide how badly the rust as spread. So, if you don't mind doing this on a fairly regular basis, then put a bandaid on it.
     
  2. soloblazer
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    soloblazer Junior Member

    Thanks everyone for the answers, and hope all had a nice Easter weekend, my next question is, since i am having a whole new bottom put on the boat, and you know how much that cost, is the weight of 1/2" plywood over top the old roof really going to be a issue? i really want to do it right, but its not going to be in the budget to replace the entire roof by pulling all the old up and replacing with 2 layers of 3/4 and fiber glassing it, not to mention its not something i would have time to do. i could put the new over the old myself and thats not a issue. but i don't want to be overloading the boat. The guy doing the bottom says he has done this before and cant even tell the extra weight on the boat. i am figuring its about 800lbs of weight counting the plywood and rubber roofing material. any other thoughts, i appreciate the doing right way of doing this but not sure if i can swing it right now.
     
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Your boat is sufficiently heavy enough that the weight will not adversely affect anything, if you do a full R&R. I do think the placement of likely a ton of material (old and new) as high in the boat as possible will affect the "tenderness" of the boat, though admittedly, probably not much.

    2 layers of 3/4" plywood seems way over the top in regard to what you actually need. Without more pictures of the structure and a better description of what's hold up this roof. 1.5" of plywood can be self supporting if applied properly, but I'll suspect it's just one layer, placed over a previous.

    What is the roof beam spacing - what are the physical dimensions of the beams - do they land on vertical supports (studs) of the same spacing - what are these dimensions, etc., etc., etc.

    It may be possible to use a single layer of plywood or a couple of layers of thinner (and cheaper) plywood. I mention this because I think your roof originally had a 3/4" plywood sheathing, then had an additional layer added at some point, and now you're looking to quadruple the roof weight over the original, which is a cause for concern. Not that the boat can't handle it, but the roof beams and their supporting fasteners.

    Rather then removing the old roof, you could consider just removing and repairing the bad spots, then maybe a new plywood skin. These bad spots will rot anything you put on top of it and will spread into adjoining areas of unaffected plywood. This is why everyone is telling you to R&R the whole thing. It's like cancer, you have to get it all or you'll just be doing this again, likely in a much bigger way, possibly with the rot getting into other portions of the boat and structure.
     
  4. soloblazer
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    soloblazer Junior Member

    Ok here is what the roof is made of from the factory from what i have read.

    2x5" rafters/studs space on 16" centers
    1/16" white board on top of them for looks on the inside
    2 layers of either 1/2 or 3/4 plywood (cant remember for sure)
    then a layer of fiberglass.

    The roof from what i understand on these boats is very very strong.

    I could cut the bad spots out and replace, but i was just thinking if i am going to go through the work of doing that i would just put all new wood on top and new rubber roof. there is a good layer of the roll on roof now so the rooted wood can not get to the new wood. (at least i dont think it can) The inside rafters are lacruared so they are still in great shape no damage to them at all as they are protected. so the only damage is the the actuall plywood roof. hope this helps. wish i could get some pics, but the boat is 3hrs away.
     
  5. PAR
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    PAR Yacht Designer/Builder

    If you just over sheath the bad plywood spots, the bad plywood will continue to rot, eventually this rotten plywood, which is under the new stuff, will no longer support the new stuff and you'll have a relatively hard skin over a couple of layers of goo and what once was wood. Sort of like nailing a piece of plywood to a mattress - somethings going to give.

    The way I see it is you're currently lucky to have caught this in an early stage, so cutting out the bad, replacing these sections and reskinning the roof (with whatever) will make it fine again. If you just stick you head in the sand in regard to the existing rot and cover it, I can guarantee, the rot will spread, possibly into those still nice beams. I can't tell you how many times I've opened something up and said, "if I'd just got to this last year", because the damage was preventable then, but now is extensive.

    Lastly, it's easier to make repairs, then skin over the whole roof with more plywood and goo. It sounds like you only have a few bad spots, so cut them back to good material, scab in some repair pieces and touch up or resurface the roof. I'd recommend truck bed liner as about the best option for the resurfacing. It's very tough, repels water and can be painted. It's also available in different colors. If you take this approach, you don't have to buy a big stack of plywood and gallons of adhesive, just enough to make the repairs and resurface.
     
  6. soloblazer
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    soloblazer Junior Member

    Ok, so do i need to sand the entire roof down to wood so i can see all the bad spots, again the rubber roll on roof covers the wood and fiberglass so i can tell which spots are bad other then just walking on it to feel for soft spots? i have attached a pic of what i had on my computer its not great but gives a idea of what is there. i dont mind cutting out the bad spots and fixing those, i am just worried ther may be other spots in the roof that are bad and need to be fixed as well. but the only way i see to do that is to said the entire roof and look for spots. look at the part right in front of AC unit

    Go to www.soundbytes.biz/roof.jpg
     
  7. alan white
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    alan white Senior Member

    Absolutely remove all the rubber unless you are certain the leaks could not have migrated there. Sanding is counterproductive at this stage. The rot is likely to be worst just under the rubber.
    All of the rot will begin at the places where the water is already getting in. The idea is to work out away from these spots until you hit clean wood (or go all the way through) ---- not dry, as wood can dry out and still be perfectly good.
    So there is a drying period involved which could go on for weeks.
    Discoloration is what you're looking for. Not just on the surface but down into the wood as well. Slight discoloration is okay but brown to black wood is no good. A hammer claw will chisel away at soft areas and a grinder with 24 grit or so will dig out bad wood fast.
    Each situation is different. A router can work wonders to neatly remove a layer of plywood. If it's two layers as you said, the the router can just graze the inner layer and maybe the inner layer is sound.
    Water likes to migrate in the direction of the grain. The inside view would normally allow you to chart the water's path but you say there's no evidence of a leak inside. Look again. Use a light askance of the varnished beams to find a water path where the dust has been disturbed. Lastly, above, drill holes in successively larger rings around the bad areas to allow sampling of the "core". You need to be absolutely sure your repair is going to last.
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    These sort of repairs are fairly common. The first thing to look for are obvious potential leak points. These would be any and all penetrations into the roof, from the weather side. These are the places screws and bedding compounds become compromised and water gets in and the first places you look. Walking around is helpful, but so it "sounding", which means you thump the roof with a mallet and check for "dead" sounds, which are indicative of wood rot.

    The rubber coating on your roof also has a life span. Cracks, checks, splits, scratches, delamination, etc. can let in moisture. All of these things are inspected too. Once on the roof, most of the obvious places will be visible. Check all fastener holes, all penetrations, etc. Discoloration, blisters, bubbles, etc. in the rubber coating too.

    With these inspections in hand, you'll have a better idea how extensive the damage is. At some point you'll have to weigh the amount of repairs necessary, against the difficulty of removing the outer layer of plywood, for wholesale upper layer replacement.

    The rubber coating will come off, if you approach it properly. A heat gun and a scraper sounds like you'll make a career out if it, so look into faster gross material removal. Sanding would the last way to go on this type of coating. Chemical strippers are the first way I'd go, followed by media blasting. If doing just spots, these could be the most reasonable methods. The rubber will likely just peel off in the rot areas.

    In a perfect world, you'd remove all the rubber coating, just to make sure you've inspected all the plywood and gotten all the rot, plus also to renew the coating, which again, does have a life span. In reality, on a roof of this size, spot repairs, patching and coating touch up is a more practical way to go.
     
  9. soloblazer
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    soloblazer Junior Member

    So if it was your boat, and knowing it has 2 big bad spots, and 1 or 2 small ones. would you replace the whole roof, just fix the bad spots, or cover over existing roof. Thanks again for all your help.
     
  10. alan white
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    alan white Senior Member

    Soloblazer, you need to answer that question yourself. The actual roof in its present condition can be analyzed but not here in this forum. If I were there I would be able to tell you what exactly I'd do but I'm not. If you can't work out a plan without professional help, you'll need to find someone near you who is qualified to analyze the repair. Your question can't be answered realistically from here. All I or anyone else can do is to suggest repair methods and materials, describe what bad wood looks like, tell you how to use epoxy, etc.. I suppose that is worthwhile help but when you say things like, "2 big bad spots", I guess I wonder what "big" means---- how big? How bad?
    You don't have to replace wood that is sound. That's been said a few times. So save whats good unless you discover that what's good is only one or two small areas. Then of course replace what's bad. Simple enough!
     
  11. PAR
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    PAR Yacht Designer/Builder

    Agreed, an assessment needs to be made and it's a judgement call, as to how much in bad spots, warrants wholesale roof replacement. From the sound of your description, you just need to make some repairs and likely surface the roof. The techniques, materials and finishes can vary quite a bit, but generally, you fix what you have to, putty in the edges of the repair, to hide it under a new coating.

    Look at it as if it was the roof to your house. You have a couple of leaks, that have left stains on the drywall ceiling in the kitchen. Damn, you got to do something. You could pull the roof off, put down new plywood, tar paper and new shingles. Conversely you could just fix the leaking flashing, around the vent pipe rising up through the roof, from the kitchen sink (or whatever). Its' your call.

    It's probable your roof coating is shot anyway, with all the traffic and UV it's seen. I dislike attempting to repair these types of coatings. It's a mixed bag - it might stay sealed, but I've noticed more often than not, it eventually leaks at the repair areas again. This is why I like to see a whole new roof coating, which by the sound of it, is something you'd planned anyway. Think of it as a single, continuous solid membrane that covers the roof. You don't want any breaches if you can get away with it.
     
  12. thegrooveship
    Joined: May 2013
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    thegrooveship A 3 Hour Tour

    I have a houseboat with a wooden deck on it and was trying to figure out if it is a bad thing or if I should just put some stain & plastic wood planks on and be happy.

    Should I remove the deck and plug any holes it made & add the old railing back or does it look like it will work for cruising? If so this might be a solution for your deck question

    I just bought the boat less than a week ago, it hasn't left the slip in 7 - 10 years I don't think & has been lived aboard with people hanging out on the deck for at least a couple of years.

    [​IMG]

    [​IMG]

    [​IMG]

    There is no sign of leaks on the ceiling so I am mostly wondering if the weight & height are going to collapse the roof or walls or flip the boat over when I hit some rougher spots (in the future when I am cruising)

    The deck works well for what it has been used for. The motors are running again and as soon as I can get some new manifolds I'll be moving. I figured the roof was soft so the deck was added but the seller denies it and the lower roof deck is very firm with no cracks in the coating.

    The boat is a 1984 Gibson Classic '44 Houseboat & everything related to the house seems to be in working order. I paid $5300 for her and assumed that it would not sink as is so everything else that works is a bonus.


    Thanks for letting me join your forum!
     
  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    Your instincts are correct, that deck belongs on the back of your grandma's house, not your boat.

    At this point it would be wise, to have a marine surveyor look her over and give you a real assessment of her actual condition. Typically, this is done before purchase, so you know what you're getting into, but since you own it, now it's time to get the real story about the boat.

    Again, the previous owner put that deck up there to "fix" something and it's obvious he hadn't a clue about marine carpentry or even land based deck building, for that matter. You can't honestly expect any truth from this fellow, he's just looking to be out from under it.

    Look up marine surveyors in your area and get a few quotes. Though these boats have engines, they're really not for puttering around much, just moving from one slip to the next or maybe chasing a school of fish on a calm lake, that's it. It's not a boat, it's a hull with a Winnebago parked on it and should be treated as such. This isn't personal dig, I like houseboats and have several houseboat designs, but just a comment about there effectiveness as a "boat" as opposed to a "house". Simply put, this design is intended to remain parked at a berth for 99% of it's life.
     
  14. thegrooveship
    Joined: May 2013
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    thegrooveship A 3 Hour Tour

    Thanks for the reply! I'm glad to get a pro's opinion.

    for the price I paid, instead of a survey I would rather put the money toward a little Boston whaler type boat I can get around the Chesapeake in. I would like to be able to get out around the mile or so of Baltimore inner harbor to watch concerts from the roof or fireworks etc on calm days but even that would be gravy on top.

    That's funny about the grandma's porch. I was thinking that something is going to be weak or rotten under the porch if not everything and it seemed like it could result in the roof caving in.

    How much do you think all that weighs? I was guessing about 500lbs which is going to make the boat really topheavy if there are 5 people sitting up there.

    I will be living on the boat with my wife while she is in Baltimore for work for a couple of years. Then sell it and go back to normal house life. So I guess it's like having a single wide trailer and a crappy boat which seems better than no boat.

    Thanks again! PS - anybody need a used houseboat deck?
     

  15. PAR
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    PAR Yacht Designer/Builder

    That deck probably weighs a lot more than 500 pounds after a rain. Stability issues can arise if you place a deck like that, up high on your boat. The original cabin roof shows a substantial crown, which suggests it wasn't intended to be used as a dance floor. Forcing it to be a dance floor or 4th of July fireworks party platform, is a recipe for trouble. Every year or so a boat load of folks end up taking a swim (or worse) because they tested the initial stability of their yacht, by putting way too many in a flybridge or on a deck like that. The space you have up there is just a remote helm and some general seating, maybe 4 people. What ever you put up there, should reflect this and if possible make putting more then this, uncomfortable and crowded.

    If it was me, I'd rip off that monolithic deck thingie and make a couple of plywood box seats, which would provide some closed storage too. 1/2" plywood, a couple of cushions on each, house paint on the boxes and you're good to go.
     
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