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Community and Q&A

Exterior trim options

jwyman | Posted in Green Products and Materials on

What are most builders using for exterior trim; fascia, soffits, door and window trim these days?

I understand the options to be wood, composite (cellular PVC), fiber-cement or a vinyl or metal cladding. Most new homes I have been involved with in my cold climate area have large overhangs, vented soffits and shingle siding with a drainage plane requiring at least 5/4″ thickness. I’m looking for minimal maintenance for a stain/paint application.

I typically use fiber-cement, but with large overhangs have problems with a thin fiber-cement panel spanning a 2′-0″ o.c. rafter span.

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  1. Riversong | | #1

    I'm not sure why you would be interested in what most builders are doing, even on a "green" forum, since the norm is rarely the best or most appropriate (or the greenest).

    I continue to use solid wood for all siding and exterior trim. In fact, I've take to using rough-sawn lumber (from bandsaw mill, so striated nicely) for exterior trim. It's a full 1" thick, takes stain very well (latex solid color stains last as long as paint but don't require scraping for refinishing), and can be extremely durable if drying potential is designed in.

    There is no greener option in the forested northeast than locally-sourced lumber.

  2. jwyman | | #2

    As this is a "green" forum, with the caption: "The complete source for Building, Designing, and Remodeling Green Homes" and "Q&A - Consult our community of building professionals for answers to your questions", I was hoping for the norm among those who participate in this site - a "green" response like yours.



    I'm working to get my local building inspectors to allow the use of TimberSil ( since seeing CEO Karen Slimak speak at the BuildWell Symposium this winter. (Sort of like Joe Lstiburek's building science summer camp but with a focus on top research on building product toxicology and resource conservation) We're trying to use it for all places where we would normally use pressure treated lumber @ mud sills, fascia and rake boards and will expand to ext window and door trim and decks after getting some experience with it.

    We generally don't worry about soffits as we use 32" exposed 2x6 rafter tails with 5/8" T-1-11 roof sheathing above. We staple our shingles with 5/8" leg 1" crown galvanized staples and have very little blow-though. Board stock is nice if you can afford the labor but we pay our people too well to be able to make that work for us.

    Until we get the TimberSil approved we're using fiber cement for exterior trim and treated for rakes and fascias.

  4. Christopher Briley | | #4

    We've used Miratec with some success

  5. Christopher Briley | | #5

    They also make a pannel product for soffits as an MDO replacement. The product is basically an exterior grade MDF. This and back vented, back primed pine is what I use mostly.

  6. Expert Member
    Michael Maines | | #6

    We use C-select eastern white pine for most exterior trim. We use some pvc for very vulnerable locations but try to design our way out of needing to resort to rot-proof material. We often use aluminum clad windows and doors; not the most energy efficient but very durable and fits our niche of traditional coastal homes better than other options.

    Soffits are usually solid pine without venting. When we do vent we use standard aluminum strip vents, or sometimes more clever designs involving window screening.

    Siding is either eastern white cedar shingles (Extra Clear grade) or western hemlock clapboards. I'd like to find a better source for clapboards, but the locally sawn vertical grain spruce clapboards are short and require too many joints.

    I really like the idea of rough sawn exterior trim and siding. If you've ever tried to paint rough sawn lumber you know it absorbs it like a sponge. Unfortunately it doesn't fit our markets' aesthetic, but I would use it on my own house.

  7. Riversong | | #7

    "the locally sawn vertical grain spruce clapboards are short and require too many joints"

    But that's the authentic traditional look. You should be able to charge a premium for it. Our local mill (Ward Clapboard Mill in Fayston VT) is one of the last original radial saw clapboard mills in the country. Those machines don't take more than a 6' bolt of spruce. But you can't find a better clapboard.

  8. Danny Kelly | | #8

    We use pressure treated, factory primed, clear yellow pine for all our exterior trim. They even make treated brick mould, shingle mould, base cap and crown moulding - so no more rotted bases on columns or rotted brick mould at garage doors where it is in contact with the groud, etc. We typically have 12" soffits here so use a 1x6, 2" Soffit vent and a 1x4 for our soffit - all 3/4" material so no problem with spans. The 3/4" square edge looks better than the typical 3/8" plywood most people are using too. The PT lumber looks better and more durable than any of the engineered products and holds paint better than the PVC products. We have seen problems with some of the engineered/pvc products when painted a dark color. The fiber cement also explands and contacts a lot too - used that for about a year but now try to avoid it.

    Here in NC the yellow pine is local (green and renewable) and Cox Pressure Treated Lumber does the pre-priming at their yard so they make sure the moisture content is proper before applying the primer. Been using it since 1996 and have never had a problem with any of it. Had to use stainless nails for a while during the ACQ phase but are now back to hot dipped galv. or paslode ACQ depending on what we are doing.

  9. Stephen Jeffery | | #9

    I've been manufacturing radial sawn white pine clapboards in lengths to 12 feet since 1993. For trim I use clear heartwood white pine, quarter sawn if possible.

  10. Jesse Thompson | | #10


    Where are you? What is your company?

  11. Riversong | | #11

    What is your company?

    Excellent question, since a man is known by the company he keeps ;-)

  12. Jesse Thompson | | #12

    Google thinks Stephen might be near the NH seacoast in a town called Barrington. "We are a clapboard mill providing radial sawn, white pine boards 4 to 6.5 inches in width and random lengths to 12 feet. We also carry beams and boards to 24 feet in length."


  13. Riversong | | #13

    Back in 1979, I used to run a Newman 500 5-head planer-matcher at Fogarty Lumber in Barrington NH (and was trained by a 70-year-old French-Canadian who invented perhaps the first planer to produce "hand-hewn" timbers).

    My planer looked something like this (except with motorized V-belt drives rather than the original flatbelt):

    In 1980, I worked at Chism Machinery in Derry NH, which re-manufactured old sawmill equipment like the planer above and resaws, swapping out flat belt pulleys and babbit bearings for multiple v-belts, ball bearings and panel-controlled motors with multiple-speed gear boxes, and making custom machinery out of old parts.

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