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Termite-resistant fascia

Tim R | Posted in General Questions on

Hi,
I need to replace my 2×6 fascia in Southern California. I want to do termite resistant – My plan is 2×6 ACQ pressure treated lumber (painted) then rip 5/16″ x 8.25″ Hardie Plank Siding to give it a finished look. I will need to cut back each rafter by that 5/16″. I decided I can live with the perforations in the Pressure treated, perhaps a thick paint job will help.
I am doing this in that I need a structural facia on the gable ends and I need a sub fascia even if I use a Hardie Fascia product.
Question – Do I need to place a barrier ( such as grade D paper ) between the pressure-treated lumber & the cement board?

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Replies

  1. Expert Member
    Malcolm Taylor | | #1

    Tim,

    No barrier is necessary between the cement-based fascia and the treated wood.

    What kind of PT wood do you get in SoCal? Neither the ACQ or MPS here has perforations. Might be worth looking around.

    Out of curiosity: Do you get termite damage that far up a house there? I would have thought by the time they got that high they would have encountered all sorts of regular lumber framing to feast on.

  2. Tim R | | #2

    All I have seen has perforations. I looked at the borate but it is lower quality wood. Getting it from the big box.
    The termites eat everything, lots of rafter tails to eat. See the photo - they ate my studs above the header, but not the header. They were covered in stucco. The seem to be quite selective in the lumber they eat. My trusses in the attic are almost termite free. The termite inspectors only write up what they see so faica is an easy catch. My neighbor had the facia replaced for $6,000 on a 1,000 sqft house. The spruce pine facia termite food is about $300 in material. so mostly labor.

    1. Expert Member
      Malcolm Taylor | | #3

      The little bastards!

  3. Expert Member
    Peter Engle | | #4

    Malcolm,

    In SoCal, they have aerial termites as well as the subterranean termites that are more common in the wetter parts of the country. The aerial termites set up colonies anywhere in the building and do not have to have access to the soil for moisture. They seem to love attics and soffit areas. Treatment generally involves tenting which is a serious PIA.

    Tim: Why not consider Azek or one of the other PVC trim products. Granted, there are valid concerns about the environmental impact of PVC use, but they are certainly termite and rot resistant. Or possibly use western red cedar. Pretty expensive but very nice to work with and moderately termite resistant (As I recall).

    If you do decide to rip cement board, use good dust collection and a respirator. That dust is pretty nasty. Cement board is also rough on saw blades, so buy cheap ones and plan to throw them away after this project.

  4. Tim R | | #5

    Hi,
    I just looked at the Azek spec sheets- for Facia with more than a 16" span applications they want a solid wood backer, it could be 1/2" pt plywood. I will need to put up rain gutters, the solid 2x will provide good support to screw into. I have a gable eave that is 24"oc with a funky down span at the eave that needs structural facia support. Thanks for the suggestion.
    I have the correct cement board saw blade and vac system on my saws, I did cement board siding.

  5. Expert Member
    Zephyr7 | | #6

    A lot of people don’t like fiber cement for trim. That’s one of the reasons it’s so common to see PVC trim used with fiber cement siding.

    I’d go with PVC trim if you’re worried about termites. Termites can’t eat plastic so they’ll leave it alone.

    Bill

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