What have you used for siding/trim/etc?
I am trying to decide on the healthiest product to use for the exterior. I know it won’t really affect indoor air quality if our house is air tight (which I hope it is), but I just really want to chose the product that is the least risky in terms of health. Hardie Board makes me leary because of the Silica. I know it is really only harmful when being cut and installed, but it just makes me nervous. What if we need to repair it or remove it and reinstall? I don’t really want to worry about silica dust being everywhere with kids. The harm of the silica dust reminds me a lot of the asbestos and I worry that, in 20 years, Hardie board will be similar to asbestos siding. In what I have read, the company doesn’t really sound like they are on the “up and up”. We have been considering LP SmartSide (strand substrate) siding and Boral TruExterior siding. We’d like to avoid cedar (not in the budget) and vinyl. Not sure on the trim/soffit/fascia either. We have thought about the LP smart side products, Azek, MiraTec, and Boral. Anyone have any experience or suggestions? Thank you!!!!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
It sounds like you have decided to avoid pretty much everything except aluminum and pine. Here in northern New England, one can find locally milled pine for very reasonable prices. I like the look of rough-sawn siding and I believe that the roughness make the paint likely to stick on longer. You are in Michigan? I don't know anything about the lumber market there but I understand there are some forests, so you might be able to find some good sources. Some people worry about it rotting, but I think that if you build with a proper rainscreen configuration so it can dry, and prime or paint both side before it goes up, it should last a very long time.
Aluminum siding isn't used much anymore--its market niche has been taken over by vinyl. But I think it's still a viable option. Making aluminum is quite energy intensive, so its green credentials aren't great, but it's not toxic.
Thank you so much for your feedback! I really feel like it is going to have to be the lesser evil unfortunately. What is the "least unhealthy"... :(
least unhealthy, greenest, most renewable and lowest GWP siding material is, I suspect, local pine as Charlie Sullivan has said. There are pine clapboards that have been on local houses for two hundred years, so it does last. Rough, vertical boards installed over rain screen will last, as has been shown by so many local barns.
There is a product called Allura and it has much less silica http://www.allurausa.com/blog#sthash.UUvDZIwz.dpbs
I used some Azek and Boral trim, but used locally manufactured white cedar shingles for siding. Look at whatever wood is available locally.
Carolyn, Even if you are the one installing the cement-based siding you shouldn't be exposed to any dust. I use shears which make virtually dust free cuts. Removing old Hardi-plank causes no dust either.
Let me allay your fears. In this context, "crystalline silica" is simply the dust that's given off when you cut a rock or a rock-based material. It's made of silicon, a ubiquitous element that is present in every rock and soil type on the planet, as well as the sand, rocks, and cement in the concrete that your foundation is probably made out of. It's almost impossible to build a silicon-free house, but that's okay, because crystalline silica is only dangerous if you breathe it in dust form--but let's be fair: this is true of most other construction dust, too. Sawdust from plywood or OSB will bring formaldehyde into your lungs. Dust from foam will contain flame retardants, halogens, endocrine-disrupting chemicals, etc. People cutting construction materials should protect their respiratory system, period. There's no need to be fearful of rock-based materials because the dust from cutting them may be harmful--in fact, rocks and rock-based materials are some of the most chemically inert materials you can have in your house when you're notcutting them with a saw (which I assume is going to be 99.99999% of the time). They don't rot or decay, don't grow mold, don't produce toxic gas when exposed to flame, can't burn at all, can't be eaten by insects, don't off-gas harmful chemicals, and will naturally last for hundreds or thousands of years in adverse conditions. Siliceous masonry is the original green material, and I would argue is much healthier and better for your family than a house full of OSB, pressure-treated lumber, engineered wood in general, plastic foam, latex paint, PVC flooring, and other modern materials. It is possible to build a healthy home out of these materials, but it requires being very conscientious about what's used where and how it's protected and isolated by other things.
Oh, Miratek is my choice of composite trim. The stuff really holds up. If something is low to grade or might be getting wet a lot, like splash back from under an eve, or I want a spot that is very smooth, then Azek is nice. Be aware that Azek is white so if you are using a darker colored paint, you need to know that a scratch will show up white. Also, when the joints meet on Azek, it behaves more like the plastic it is and less like wood than wood or Miratek or other trimboard products. Gaps may open up more easily. There is a good article in Fine Homebuilding, maybe a year ago about working with Azek. It speaks to using PVC cement, trim screws, and caulks to alleviate some of the issues.
Carolyn,
Your questions show a concern for health -- perhaps a concern for worker health as well as building occupant health -- not durability. Even if your health concerns are unfounded, my guess is that you will be happiest with wood trim.
While Charlie and Bob like pine, I don't. Here in Vermont, exterior pine trim rots fairly quickly. I like to use white cedar (purchased from a local mill) for trim. You don't have to paint it unless you want to.
Martin, you mention that you don't like pine trim, which is perfectly understandable... what about pine board siding? It seems like a viable alternative...
Certainteed Cedar Impressions polymer siding is made from polypropylene, a form of plastic that doesn't contain the toxins that vinyl has. My friend, who worked in a lab, was always impressed with how stable and safe that polypropylene was to work with. The Cedar Impressions product receives really great reviews for durability and longevity, too. But using locally sawn wood wouldn't use up so much oil in production.
Ethan,
Pine siding isn't as durable as red cedar or white cedar siding. But it can last a long time, as long as (a) the house has wide roof overhangs, (b) there is a big gap between grade and the lowest course of siding -- I like to see at least 18 inches, and (c) there are no decks that contribute to splashback.
I think your fears about silica somehow coming loose and getting into your lungs are completely unfounded. You should also avoid concrete then. Unless you cutting the stuff up with a saw and making dust for the rest of your life. I can't even imagine how there could be an issue. The stuff is painted and doesn't crumble all over. I just can't grasp what the issue is.
Joe,
I'm not sure that realize that you are responding to a two-year old question...