Choosing materials is one of the most difficult things in green building, because there often aren't clear cut choices.  In order to understand this section, you will need to be familiar with the materials to some degree, so go read the materials section in the tutorial if you're not.

The following is a collection of our initial thoughts on various materials.

Structural Materials

Flyash concrete: you can't easily avoid concrete in house, unless you don't create a basement and use a post & pier or pin-type foundation, but we wanted at least a partial basement  (see needs).  Flyash mitigates the use of concrete to some degree, and hopefully there will be some effort to make more flyash useable in the future. Concrete runs around $75/cu yard, and adding flyash only add $1 or so to the cost. There seems to be no downside to using it, but it does require a change in the way the concrete contractor works, because it cures slower.  Some concrete suppliers have adopted using a small amount of flyash (15% or so) by default doing so doesn't change the workability.  We will use a 43% mix for all walls, and at least a 25% mix for slabs.  The lower mix for slabs, is because there are more workability problems.  A 50% mix has been used for both walls and slabs successfully (the Puget Sound Environmental Learning Center), but the contractor doesn't feel ready to try this high a level at this point.

ICFs:  We considered using an ICF system (in particular Rastra, since its recycled), but the additional cost was significant (a few thousand dollars), and we currently had no real plans to heat any space in the basement.  The concrete savings is significant, so it is truly unfortunate to have to make this choice.  An interesting aside, is that it makes no sense that an ICF system using six inch diameter cores would meet structural code, but a six inch thick solid foundation doesn't (code requires eight inches).

FSC Certified Lumber - ideally all forest products company ought to manage their forests sustainable and FSC ought to unnecessary, but the status quo is just the opposite.  By buying FSC certified wood, you are at least sending a message that you prefer that product over non-certified, and usually there is some price penalty for this choice.  Unfortunately there is a limited supply of FSC certified wood available, and sometimes the cost is prohibitively higher (like three times), but often the cost is almost the same.  Our strategy is to use as much FSC certified wood as we can get with only a small price penalty.

Engineered Lumber: almost everyone uses engineered lumber these days, so its not really an environmental product anymore.  We requested that the structural engineer use Glulams when possible to avoid the use of timbers that could potentially be from old growth.  At one point we had steel beams in the design, but when we decided to redo the foundation, we could avoid a lot of beams completely.  

Plywood .vs. OSB - although OSB often comes from fast growing plantation trees, there is no reason to believe that these forests are managed in a way that is better for the environment than conventional logging.  Currently these is no FSC certified OSB available, while there is FSC certified plywood available.

OSB:  The contractor avoids using OSB due to its vulnerability to water damage, for which there is some documented evidence to support this, because it absorbs more water than plywood due to have exposed end-grain.

SIPs: this is a product that demonstrates how difficult choices can be.  Environmentally, they have arguments both for and against them. Bob has a reservation about the possible failure of these because an SIP is only strong as long as it is intact: its components are so weak they can't even hold their own weight up over any sizeable span.  The fear is that an SIP can't take much damage before it completely collapses, but there are strong arguments as to why this fear is unreasonable.  First is that the typical house never experiences any damage at all, so the risk is low.  Second is that the alternative to a SIP roof is to use stick framing with TGIs, but they also are made of materials that aren't that strong by themselves.

The question becomes one of how much damage can an SIP sustain and whether this amount is significantly smaller than the alternative systems, and whether the difference is even relevant.  Because glue is often the strongest part of any engineered system, its not likely that the SIP will delaminate. 

Energy wise they perform very well and they tend to reduce wood use and avoid using old growth (a final analysis will be in the construction section). In retrospect we probably would have just stick framed with TGIs, but there aren't really any good arguments for doing so.  The only "safe" would be to use dimensional lumber, but that would require using 2x12's (and the likelyhood that they came from big trees) and much more structural support, since 2x12 aren't strong enough to span the length of the roof.

Reclaimed 2x4 (also steel framing) - one way to reduce wood use is to use alternatives for non-load bearing walls- either the light gauge steel typically used in commercial construction or reusing 2x4 from a deconstruction project.  Unfortunately our existing house has 7'7" ceilings, and we wanted 8' ceilings which will help make the house feel bigger.

Fiber Cement siding (Hardi-Plank) - a composite of cement and wood fiber (that in the past was imported from Australia, and may still be), Fiber Cement siding has become very common, with Hardi-plank composing the majority of the market.  Although it is easy to argue that fiber cement siding isn't all that green, the alternatives aren't much better.  Wood siding is the traditional choice, but is not a top choice of most consumers because it requires frequent expensive maintenance. Cedar siding has been a preferred choice of wood siding, because its natural tannins give it a resistance to rot, but cedar only grows in low elevation forests in the Pacific Northwest and is becoming a scarce resource.  Composite wood products, like LP siding, were very popular for a while, but due to a vulnerability to water damage (and a huge nationwide class-action lawsuit against its manufacturer), was dropped like a hot potato by most builders. In the past Aluminum siding was popular, but vinyl virtually knocked it out of the market because it doesn't dent and costs much less.  Due to pressure by environmental groups, alternative materials like Fiber-cement have become more popular, which has the advantages of being durable an dimensionally stable (vinyl can expand as much as 1" across the length of a house in the summer heat).  The green building community is waiting for a better product to emerge.

Cellulose Insulation - the advantage of cellulose is that it is 100% recycled, has a slightly higher R-value per inch than fiberglass and is dense enough that very little air leaks through it, even without an air barrier installed.  The downside is that it relies on borates to act as a fire and insect retardants. 

Roofing - we would like to do metal, cause its recyclable, and often has recycled content.  Our backup choice is composition, because its the cheapest.

PEX pipes- due to lower overall cost, PEX is taking over the plumbing market, but it because of the way it is often results in lowering hot water consumption, with no apparent issues with anything toxic leaking into the water.  Since we don't like the taste of chlorine, we use a filter for our drinking water anyhow (which unfortunately probably removes the fluoride that is put in water to help your teeth!).

Finish Materials

A Note on Using Reclaimed Wood
There is a variety of reclaimed materials available, both in size and wood type.  A key aspect for reclaimed wood is how much processing it will take to make the wood usable.  Some will already be in the right form for the application (ie flooring), but others will need a variety of processing to be made usable.

Flooring is one of the most common, and one of the easiest to use.  It comes either as freshly milled from larger beams or as existing flooring.  As the worst case you will have to remove nails, stapes or any other foreign material and scrap any excess old finish off the edges so the boards can be fit tight together again.  Although its relatively easy, its still a lot of work.

Reclaimed dimensional lumber is also available, and when used for framing it needs only to have most of the nails removed from it.  When used for finish lumber, significantly more processing is required.  Often wood is available custom milled from larger timbers (ie old warehouses, railroad trestles, etc), in which case it comes free of nails, and usually surface planed as well.  Still depending on the grade, it can have many knots (including loose ones), checking and other types of cracking, nail holes bolt holes and other defects.  Despite these issues, the wood is typically very beautiful, and often from large old growth trees of the variety that are no longer available (or at least they shouldn't be!).

FSC madrone - Madrone is a native species in the Pacific Northwest that has been traditionally ignored because it is not straight and tends to warp when dried.  A number of people have learned to get around these problems, and  the results is a very beautiful wood that looks much like cherry.  We've had a few price quotes in the range of $5 to $5.50/SF, which is about $2/SF more than ordinary Oak.  We are going to use about 400SF of it, so our additional cost is about $800.

Reclaimed flooring - the house has about 550SF of existing oak flooring, but until we attempt to remove it we don't know how much will be usable. We do have the option of buying additional reclaimed flooring, but have not investigated it.  The flooring contractor has a concern that used flooring has been sanded down to far to be worth the cost of installation, so we will measure the thickness of any used flooring and determine whether this concern is warranted or not.

Cabinets  - our local cabinet maker does not usually use FSC certified wood (which he says costs about 20% more), but claims that his sources of wood are from small woodlots that are typically well managed and aren't FSC certified because the cost of doing so is beyond their budget.  Because the cost of labor is more significant than the cost of materials, this doesn't increase the price much.  Any way you look, custom cabinets are not cheap.  We looked into one alternative supplier who does FSC as standard product (Neil Kelly, supplied by the Environmental Home Center), but they were not made locally and slightly more expensive in the end.  As it turns out, we wanted a significant number of non-standard features,the most significant one being Finnish drying rack (reference: Goldbeck, The Smart Kitchen ...verify this!), which we didn't end up getting right in the design.  Had we not already had a relationship with the cabinet maker, and the builder also having a long term relationship, we would have used the Neil Kelly Cabinets.  

Ceasarstone/Silestone - this countertop material is composed of 94% quartz particles and 6% acrylic resin, which produces a very hard, durable surface that looks much like real granite.  Compared to other solid surface materials like Corian and Avonite, it uses much less resin, although we have no data on the environmental impacts of the various resins.  We considers concrete, but it is actually more expensive, apparently due to the cost of polishing the surface.  We also considered tile, but grout around the kitchen sink is a disaster waiting to happen, and is difficult to keep clean.  Laminates are cheap, but show significant wear after only a few years, and are wrecked in as little as five years.  Wood is natural, but not a durable as solid surface materials.  Granite is durable, although can be stained by oils, and needs to be sealed periodically and is typically very expensive.

Non-toxic paint - we can't think of any reason not to use non-toxic paint as the cost pre gallon is only a couple of dollars, and performance is comparable.  The only issue is the lack of an oil based non-toxic paint: we have tried a number of latex enamels, and they don't produce the nice smooth, hard finish that alkyd enamel does.

Non-toxic floor finish - we know of no cost or performance difference between the two, although they do come out different colors.  Traditionally Swedish finish yellows the wood somewhat, while the non-toxic finish lightens its. 

Clear trim finish - still under investigation.  So far we have looked as OS/hardwax oil, but applying is time consuming.  Its best feature is that it is easy to touch up at any time in the future.