Ideas to repair a Leaky shipping container roof

Discussion in 'The Garage' started by overlandr, Mar 21, 2013.

  1. overlandr

    overlandr Dystopist

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    Ok so I bought an 25+ yr old 40' shipping container cheap as a workshop. The main immediate problem is the roof in one area that has obviously had rain water pooling on it for some 10+years with the Ozzie sun bearing down onto it relentlessly.
    From inside I noticed a single rusty blister 2" OD with evidence of a small leak below. On the outside of this area, there is an area about 2' x 1' with severe rust. By this I mean multiple thin layers of steel rusting come off when nudged by a screwdriver. I created two small holes (1" sq) easily so then stopped. The container steel is about 0.125" thick - maybe more. I only need to keep the container for another couple of years or so welding is uneconomic.


    I am thinking to

    1 Get a paint scraper and gently remove all loose flaking rust.
    2 Apply some rust neutraliser from above and below and allow capillary action to get it into the
    smallest of crevices (phosphoric acid from memory?)
    3 Wash off any residues of the acid after a few hours.
    4 Apply a rust priming paint that will further neutralise any rust
    5 Apply a two pack epoxy filler compound all around the rusted areas from above and below

    Would be interested to hear of any ideas as to what I could do to stop the rust from progressing and rain leaking in?
    #1
  2. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Well, fortunately it doesn't have to pretty, does it?

    Know anybody who welds? The best fix is going to be to remove the rust, cut out all the bad metal and weld/have welded in a new piece/s and then paint.

    Got any pics?
    #2
  3. sailah

    sailah Lampin' it

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    I can't imagine that someone you know doesnt have a welder that would be a very quick job.

    Cut out a piece of steel oversized, lay it down and run a bead.

    Or just use some roofing tar and lay a piece of plywood down and caulk the edges
    #3
  4. H96669

    H96669 A proud pragmatist.

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    Get some construction adhesive, the stuff designed for decks and subfloors.You are down there so can't give you a product name,up here that would be Lepage PL-400. Cut a steel patch and glue it there. Maybe a few metal roofing screws and some plywood backing on the inside for the screws to go in.

    You'll get two years out of that....already got 10 or so from such a repair on galvanized steel roofing.
    #4
  5. bomber60015

    bomber60015 Anatomically Correct

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    quick and dirty welding wouldn't be much, if any, cheaper than any of the alternatives, unless there are Oz-specific cost factors I don't know of (certainly a possibility) . . . . . . .
    #5
  6. overlandr

    overlandr Dystopist

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    Thanks but welding is just a much bigger job. I'd have to source steel, cut it to size, a friend I know has a welder but he's not a good welder and there could be a large voltage drop on the end of a long extension lead - the bottom line I'm looking for an easy quick repair that keeps the water out for 2-3 years only. Welding steel would be complete overkill and waste of money as the container is rusting (gently!) all over.

    Guess I'm fishing for ideas that are non-welding related.
    #6
  7. overlandr

    overlandr Dystopist

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    Yep I was thinking of something along those lines - silicone bathroom sealant always seems to be hard to remove and I have some tubes of that kicking around.

    Edit: We have this stuff called "liquid nails"

    http://www.selleys.com.au/trade/building-products/construction-adhesives/liquid-nails-high-strength

    but just found this below.

    Bonds weaken at high temperatures (e.g. above 50°C). Avoid bonding metals or heavy materials which will be heated by direct sun, e.g. to metal roofing and siding. (Consult Selleys about particular applications subject to heating.)

    Bugger!
    #7
  8. sailah

    sailah Lampin' it

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    If welding is out use one of the adhesives methods but not epoxy. Construction adhesive explained above is a great idea and it's cheap, very cheap, almost no tools required.

    I wouldn't bother to clean the rust away but I would clean the surface where the adhesive is going. And by clean I mean reasonably so it will adhere well.
    #8
  9. Foot dragger

    Foot dragger singletracker

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    Build a quicky roof over it and be done with it,12 pack o beer,some 2x4's,4x4's,then some sort of sheeting,plastic? over the top.

    Or Maybe a shed roof style with the 1 raised edge for run off,that could be done with metal or wood attached to one edge and sheet over the whole thing.
    A layer over the top would deflect some heat with luck in the summer.

    It would require some bodgy engineering,that's where the beer comes in.
    #9
  10. overlandr

    overlandr Dystopist

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    I think I'm narrowing in on a solution = sikkaflex 291.

    http://usa.sika.com/en/solutions_products/01/01a006/01a006sa01/01a006sa01100/01a006sa01101.html

    I used this marine sealant a couple of years ago and it really stuck well to wood, glass, steel and perspex - I tested it compared to silicone and construction sealant and it excelled. Most importantly, it can seal below the water line AND work up to 194F

    Service temperature permanent -40° - 194°F (-40° C -+90°C)

    I think it'll work well with some sheet steel - I'm going to still use a rust cure to stop the rust.
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  11. overlandr

    overlandr Dystopist

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    Thanks but its going to have another container on top!
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  12. H96669

    H96669 A proud pragmatist.

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    You have Sikaflex down there....go for that.That's good stuff.:clap Stay away from the sillycones, I have tried that on roofs and that always fails after a few years. Better and maybe available are the Butyl type caulkings, they are non hardening and that worked well on my old roof had to recaulk all the nails many years ago, still holding where the sillycone failed.

    Went and rechecked the specs on the PL-400, good to 60C, service temperature so probably good for higher temps but that metal sure gets hot in the sun.

    I am not a big fan of the Phosphoric Acid based rust converters, the clear type ones. Much better results with the Tannic Acid based ones, they are usually milkish white in appearance. Just bought another liter at the boat shop....pricey but well worth it.

    Server errors this morning so can't get into their website....lookup Corroseal "rust converting metal primer".....good stuff.:wink:
    #12
  13. overlandr

    overlandr Dystopist

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    As you say, container roofs can get very warm sothe higher service temp the better. 60C is not high enough and as SIK 291, being marine grade, can be used below the waterline, its the winner. Must assume that after heavy rain, the roof will be sitting in a poll of water for a several days. I checked the video on yr corroseal but it seems very that the surface must be meticulously prepared which is impractical for me. So will stick with the P/acid in the meantime. I just need to find some sheets of scrap steel. maybe an old oven chopped up??:evil
    #13
  14. pantera1

    pantera1 Adventurer

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    Cut out the 1' x 2' rust area and glue down an auto side window from the salvage yard using windshield adhesive.

    Instant skylight!

    Any auto parts store will have the adhesive, and it should hold up well to the baking sun.
    #14
  15. preppypyro

    preppypyro Been here awhile

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    If you want very instant and very cheap, get yourself your favorite brand silicone/gooey crap that will stick, get a tarp, and then "glue" it down. Might have to redo it every once in awhile, but it would be cheap and quick to repair.

    If I were in your shoes, I would source out a welder and some steel and repair it correctly though. I tend to not "repair" stuff cheaply as I hate redoing things.
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  16. oldxr

    oldxr Long timer

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    Some sheet tin or aluminum and some windshield adheisive should fix it.I would clean the area around the hole with a wire wheel on a drill .Slap the patch down with the windshield glue.If you wanted to you could put roofing tar on the whole patch after the glue dried.That windshield glue is mean stuff-I think it is urathene based.
    #16
  17. concours

    concours WFO for 41 years

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    RTV will last two years easily. Cut the end off the (multiple) tube, (not the nozzle, the TUBE!) and push it out with a hammer handle. Trowel to suit. Throw a scrap of metal (road sign) over it to shield UV. Done in 10 minutes.
    I've seen it done inside million dollar machinery, lasts nearly forever.
    #17
  18. lnewqban

    lnewqban Ninjetter

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    This is the best solution, in my opinion.

    You cannot stop that rust from progressing, no matter how much you cover top and bottom; it is a microscopic thing.

    The same rust will make any welding very difficult, and each weld joint will rust faster itself.

    You can combine this solution with desirable roof insulation.
    Roof paper+bull tar or some UV-resistant plastic film would reduce the costs.
    #18
  19. H96669

    H96669 A proud pragmatist.

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    Meticulously prepared....funny.Wouldn't be me, scrape the loose stuff and apply. Just what I did on the mower deck a few days ago.:rofl I should dig out my test piece, half done with the phosphoric, the other half with Corroseal or possibly "Conquest by Chemsearch", don't remember been a while and the piece has been under the weather all winter.

    Just that them Tannic/Gallic Acid based ones dry faster (20 minutes) and give a much better finish. The term is Polymer, that's what the converter turns the rust into. Phosphoric does the same but looks more like a clear varnish when the Tannic/gallic ones are nice and black.

    Yep....seen a lot of corrosion "at sea" in the last 30+ years. Lots of Sikaflex and Corroseal/Conquest used.
    #19
  20. Maggot12

    Maggot12 U'mmmm yeaah!!

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    Remove the side off and old washer or dryer (it's galvanized) and gluing it down, with the forementioned adhesive.

    I like the windshield skylight idea too....
    #20