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  1. #1
    Join Date
    Oct 2009
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    2

    Default bleed through exterior

    i had a contractor rebuild my home in coastal mississippi. we finished end of july 2009. he used pre primed pine for the exterior trim, then (i think reprimed) and painted with oil base duration by sherwin williams. i keep getting bleed wood bleed thru, what seems to be sap drips and some black mold.
    any ideas what could be the reason. he insists it is not the preprimed pine being used exteriorly. anyone please advise. it has been cleaned a repainted once under paint warranty. thanks j

  2. #2
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: bleed through exterior

    was the paint shellac based? and what did they use for fasteners, if galvanized was used this could be the culprit. when installing wood siding stainless steel is the only option. the tannins in wood will always react with galvanized fasteners causing bleeding
    fire up the saw and make some dust

  3. #3
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: bleed through exterior

    Quote Originally Posted by jeff haro View Post
    i had a contractor rebuild my home in coastal mississippi. we finished end of july 2009. he used pre primed pine for the exterior trim, then (i think reprimed) and painted with oil base duration by sherwin williams. i keep getting bleed wood bleed thru, what seems to be sap drips and some black mold.
    any ideas what could be the reason. he insists it is not the preprimed pine being used exteriorly. anyone please advise. it has been cleaned a repainted once under paint warranty. thanks j
    The "sap" oozing from your trim boards is a natural product of the wood...... actually called pitch.

    Ther pine is a member of the conifer species which have large pitch pockets.
    When the wood gets hot enough the pitch melts and runs out of the lumber .

    Properly kiln dried lumber that has been heated to more than 160 degrees solidifies the pitch usually does not suffer from this problem. Likely the lumber used for your trim was either not kiln dried or wasn't dried at a high enough temperature to cause this solidification.

    There's not a lot you can do about the problem at this point except live with it or have it replaced. As the trim boards heat up the pitch will continue to run from the boards.

    There is no sealer made that can contain it under these conditions.

    But the news is not all bad ........ a bit of turpentine on a rag will remove it quickly and eventually the pitch pockets will run dry ( in a few years ).

    As for the black staining it could be from the fasteners ---- especially if they didn't use coated or stainless steel.



    Hope this helps.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  4. #4
    Join Date
    Apr 2010
    Location
    I'ma Maina!
    Posts
    3

    Default Re: bleed through exterior

    Read your question again, and are you having knot bleed thru? Also, Duration by Sherwin Williams doesn't come in oil base, only latex. If you have the pre-primed pine, than quite often the primer on it isn't a very good one and is usually rather ruff. If this was not sanded before it was painted, than the paint will not be smooth and could be allowing mildew by not shedding water properly. I have also seen this wood with mildew on it from the start, and if this was painted over than it will continue to be a problem. If you want to fix this so it will not be a problem, you will need to sand the wood down to fresh wood. Start with a random power sander, either orbital or 1/4 sheet, and 50 grit. Work the areas quickly with the sander and keep it moving or you will heat the paint too much and end up with a burnt mess. Don't use a drill with a sanding pad, it will be way to much! Work up to 180 grit, and then you will be ready to prime. You will need to start with an oil based shellac, and spot prime all knots and nails. Fill nail holes and any cracks or joints with a paintable siliconized acrylic caulk. Prime the entire board with A-100 oil based exterior primer. After the A-100, you will be ready for the finish paint. If you have the primer tinted 50%, you will have better coverage with your finish paint, but still be able to see what you have or have not covered. The finish should be two coats of Duration Exterior Eg-Shel or Semi-Gloss. Don't use plain flat, as flat paint doesn't shed water as easily, and general have less mildew resistance. This should take care of your paint for quite a few years.

    I am a painting contractor and have been doing it for many years, so these are the steps that I would do myself, and have had great success with it.

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