Using Sikaflex or another sealant

System
System Posts: 2,511 admin
in General Solar Power Topics #1
Does anyone have any first hand knowledge about using Sikaflex as a sealant when installing solar panel mounts on an asphalt shingle roof? Do you know where to buy this stuff? What have other people used for sealing around footings and lag bolts? Thanks...
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  • System2
    System2 Posts: 6,290 admin
    #2
    Re: Using Sikaflex or another sealant

    Sikaflex is common sealant used by sailors. Most marine stores carry it as well as 4200, a 3M product. The latter is probably the most common marine sealant for doing jobs like bedding hardware to the deck. Forty-two hundred is tuff and close to, but not totally permanent. On the otherhand, if you want permanent 5200 is the stuff.
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  • Frank
    Frank Solar Expert Posts: 54 ✭✭✭
    #3
    Re: Using Sikaflex or another sealant

    Also be aware that there are quick-dry versions of either 4200 or 5200. Most people just use roofing cement (tar) to seal around roof penetrations though. Not sure how the 3M products would respond to direct exposure to sunlight (if there is any)? When used as bedding compounds they're usually captured between a piece of metal and wood.
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  • jimwilks
    jimwilks Registered Users Posts: 7 ✭
    #4
    Re: Using Sikaflex or another sealant

    So what is the best sealant to use for mounting rails to ashphalt shingle roof?

    And how about sealing penetrations through the roof for conduit, etc.?

    I'd like to do this just once and have it last for many years to come...
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #5
    Re: Using Sikaflex or another sealant

    There are many types of Sikaflex also. The kind I used was for teak decks on a sailboat. It is probably what you want but I can't remember the model/type of sikaflex. It was great for movement of a wood deck veneer over fiberglass on the ocean. Any decent hardware store can get it. Check the jewelry store West Marine.com
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #6
    Re: Using Sikaflex or another sealant
    jimwilks wrote: »
    So what is the best sealant to use for mounting rails to ashphalt shingle roof?

    And how about sealing penetrations through the roof for conduit, etc.?

    I'd like to do this just once and have it last for many years to come...
    The best way to do it is to use a flashing-type product that slides under the shingle. Goop up the bottom of the flashing with standard roofing sealant (elastomeric stuff works great as it remains flexible) and it will be extremely durable.

    I always worry about leaks when I see installs that simply mount tabs to the roof with a bit of sealant underneath, though I think that leaks would still be pretty unlikely unless the mount completely fails.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #7
    Re: Using Sikaflex or another sealant

    Persnoally, I use Sonneborn NP1 single part Polyurethane caulk. It is similar to Sikaflex, but, in my uses the Sika can turn gummy/sticky.

    Have used the NP1 around the feet supporting PV Racks on roofs, including asphalt shingle roofs. It holds up in the sun, and retains its elasiticy, and has strong adheasion. It is available in many colors. It is commonly used in roofing applications.

    Sonneborn also makes other polyuerthane caulking products.

    A random selection from a Google search:
    http://www.dhcsupplies.com/store/p/2-Sonolastic-NP1-Sealant.html

    NP1 is commonly available at roofing supply dealers. I've seen Sika products at Ace Hardware stores, at least in the US.

    I have no connection with Sonneborn or the company in the link. YMMV Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • LucMan
    LucMan Solar Expert Posts: 223 ✭✭✭
    #8
    Re: Using Sikaflex or another sealant

    I use "PL" brand polyurethane roof and flashing cement it comes in a caulk tube, found it to be the best for anything roof related. Available at HD.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #9
    Re: Using Sikaflex or another sealant

    Best roofing sealer I've found is called "Through The Roof".
    Mudge Fasteners has a deal on it along with S.S. lag bolts
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #10
    Re: Using Sikaflex or another sealant

    Does anyone know if one can use Sikaflex to completely seal an underground electrical connection? I need to connect 2 normal AC cables underground and was thinking of just using a normal screw terminal connector in an IP65 box, then encase the terminal connector in sikaflex to prevent moisture from getting in. Will it work?
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #11
    Re: Using Sikaflex or another sealant
    stephendv wrote: »
    Does anyone know if one can use Sikaflex to completely seal an underground electrical connection? I need to connect 2 normal AC cables underground and was thinking of just using a normal screw terminal connector in an IP65 box, then encase the terminal connector in sikaflex to prevent moisture from getting in. Will it work?

    You have to be careful as there are several types of Sikaflex. The gooey will never get hard, keeps out seawater, used since time began is "polysulfide" based. It is available in tubes or as a 2 part. It is date code sensitive!

    You know electricians have been taping spilt kearny nuts for decades and just covering it with dirt. If you are in a weather box and still worried I have to tell you that you need more projects. Good Luck!! and yes, I have electrical embedded depth sounders, a sonar or two, and knot logs in polysulhide. Great stuff!
    Put it in 5200 and even the big guy can't get in!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #12
    Re: Using Sikaflex or another sealant

    Thanks Dave. I asked a local electrician's shop about what I should do and they wanted to sell me some sort of kit which consists of a mold and epoxy for.... 40 Euros!
    I already have some sikaflex that gets sort of hard, tuns into the consistency of rubber and have used it to seal a leaking water tank inlet. Amazing stuff.
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  • BILL S
    BILL S Registered Users Posts: 1
    #13
    Re: Using Sikaflex or another sealant
    awirtz wrote: »
    Does anyone have any first hand knowledge about using Sikaflex as a sealant when installing solar panel mounts on an asphalt shingle roof? Do you know where to buy this stuff? What have other people used for sealing around footings and lag bolts? Thanks...

    We use the sikaflex caulk and the NP 1 caulk both are excellent. we install a product called Duradek, it is a walkable roof membrane. Then when we install the Durarail, a powder coated aluminum Railing system, We surface mount the posts. We drill the holes and fill the holes with the polyurethane sealant, then dip the screws in the sealant and attach the posts. We have not had any leaks with this caulk. In my opinion its probably the best caulk you could use. I have never actually used it on a shingle roof but I cant help but think it would do just fine I think it would hold up better than any other asphalt based caulk out there. you can buy the Sikaflex at white cap supply, The NP1 can be bought at ABC supply (Bradco) or the roof center. We started off using the Sikaflex and switched to NP 1 I think its a little easier to work with. But both should do fine. I hope this helps

    bill
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