Sourcing Sustainably Produced Plywood
user-2701121
| Posted in Green Products and Materials on
I’m building the interior of a van and would like to use as much natural, sustainable and non-toxic materials as possible. Wondering if people might have suggestions on where to buy plywood that is naturally scoured, and held together with non-toxic glue? If this type of plywood exists, wondering if it has different integrity than regular plywood. It won’t bear much of a load, just kitchen cabinets and a shower enclosure. (Bed will suspended and retractable.)
Thanks for your ideas and suggestions!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Sounds like a groovy project. Via BuildingGreen (a trusted source), I found this product: PureBond Hardwood Plywood.
Plywood by its nature is made from large, old trees, usually old growth. OSB and other engineered products are made from chips and other smaller pieces, so can be sourced from smaller and younger trees, even species that traditionally had little value. At face value OSB can be a more sustainable choice.
But...the devil is in the details, and it is hard to ensure that the panel product you choose is sustainably sourced. In terms of health, I would guess plywood has fewer nasty chemicals. OSB dust in my coffee is a pet peeve.
The coastal forests of sitka spruce in my local area largely went to the peeler for plywood.
I'm sure it's variable, but I can't imagine plywood, by and large, is still made from 'old growth' or even particularly large trees (larger than osb, sure). I'm really not sure but I would be surprised to see high value trees going to core ply. Once upon a time I'm sure. Finish plywood with show faces does use quality 'veneer grade' logs for the faces.
Here's an interesting video: https://blog.plyco.com.au/how-is-plywood-made
'Then and now.'
A forester I know implores that we drop the term 'old growth' since it often lacks precise meaning or is misused. Is it referring to an ecosystem (late successional)? An 'un cut' forest, meaning it was never cut by Europeans? Simply a certain age of tree? What about the younger trees in the late successional ecosystem? Does the growing condition matter or only age?
I was recently in a forest declared to be undisturbed by European logging. The pines, while large, were not as impressively large as one might have expected based on the declared age, but their growth rings were extremely close together (as shown by a felled example) and the bark had a particular look unlike other specimens of similar size that are younger. The canopy was remarkably open (and layered) in places too, with relatively smaller but also very old hardwoods in the mid to upper canopy and a mix of younger growth in the mid to lower--all the way down to saplings amidst the horizontal decaying downed giants.
I'm not really an expert with forestry, but my understanding is that aside from hardwoods, very little commerical lumber is sourced from what most people would consider 'old growth' forests. Almost all regular lumber is basically farmed now -- it's a crop, just a crop that matures over decades instead of a season or two. One of the reasons that we have lower quality lumber than we used to is that these farmed trees are often selected to be fast growth varieties, which tend to produce a less dense wood. Less dense wood means softer lumber, which isn't as strong.
I remember watching a documentary about plywood and they were using smallish logs for it. One of the advantages to plywood apparently is that they have more flexibility with the logs they can use. If you really want extra green lumber, OSB and particle board can be made from what is often essentially leftover wood materials, which is a form of recycling/reuse of materials in a way. The lumber industry tries to maximize their efficiency in terms of materials use, so some of the products we have today allow for more of a tree to be used in a productive way, which is a Good Thing.
I'm interested to see if anyone knows of any materials made with unusual adhesives though. I think most of them are made with polyurea, which is excellent as a stable adhesive once cured, but the compounds used to make it are pretty nasty before they've cured.
Bill
In my experience it's a trope that we have lower quality lumber than we used to. I've lived almost my entire life on the east coast, where the old growth was cleared hundreds of years ago. Once the circular saw mill was perfected, around the time of the Civil War, they would cut up anything that grew. Hundred or hundred-and-fifty year old lumber isn't appreciably denser and doesn't have tighter growth rings than what you can buy today. I've seen 2x6's that were 150 years old that must have been cut from a tree only slightly more than 6" in diameter, because there's bark on both edges! I can believe that in other parts of the country it's different.
In my experience modern lumber is a much more consistent product than it used to be. If you look at a balloon framed house from 120 years ago the studs and joists are all over the place in terms of size.
Prior to circular mills, it was expensive and labor-intensive to mill lumber, and they only milled good logs. So really old lumber -- like 200+ years -- tends to be good wood. But there's not much of it, America was a poor country then, buildings were generally cheaply built and didn't last long.
It's not so much the age of the tree, it's the species of tree. The fast growing species tend to produce softer, less-dense, wood, regardless of how old they are. Remember that with a tree, it's only the outermost ring, just below the bark, that is actually alive. The inner part of the tree "was" alive, but is essentially just structural framing for the tree's futures after the year where it was the outermost part has passed.
The way I deal with this is to use "regular" lumber for "regular" applications (studs, normal joists, etc.). When I need something to be extra beefy, such as when reinforcing a wall or stiffening a bouncy floor, I'll spec southern yellow pine, which is the densest/strongest of the normally available pine species. I'll ocassionally spec MSR (Machine Stress Rated) lumber for certain applications, which is actually tested for strength by a machine and not just visually graded like #2 and #1 lumber is. MSR lumber is about the best you can do for knowing for sure how lumber will behave structurally.
Design and engineering is really all about knowing the properties of the materials you're working with and applying them appropriately. Lower quality lumber can be frustrating, but you can design around that issue for critical spots, just know that the better stuff costs more and usually has a lead time to order in.
Bill
DC,
I think there is some truth to what you say. Certainly milling processes have gotten more efficient and (on average) more precise. However this is a complex topic and I believe there is a reason for the prevalent notion that wood of old was, in many ways, superior.
Certainly there was once a greater supply of clear, large, and tight grained lumber (agree on that?). Is your argument that that is not actually superior, or is your argument that it was used up so quickly that for much of recent history lumber was second growth of lower quality, perhaps similar to today? Those are two very different arguments.
If the argument is the latter, I think the answer would certainly be 'it depends.' Depends on the time we are talking about and on the state of the resource in a specific geographic area.
The quality (specifically the growth ring density) of lumber is not just about species either, it's about growing conditions. For more on that, here is an interesting read: https://extension.tennessee.edu/publications/Documents/W253.pdf
I would also add that while much timber is grown as 'farms' or plantations today, there still exists management practices that are a bit in between, i.e. forest that is 'managed' but is decidedly not a plantation. Much of Maine is this way, with harvests occurring in a variety of stand types and for a variety of management objectives, but the area is not a plantation. Many of these areas are managed for more than single tree species and growth rates.
Replying to Tyler's post #8, I mean the second -- around here old wood doesn't mean it has tight rings. I've taken down plenty of walls that were 100+ years old and the ring spacing was around four to the inch.
An anecdote: I own some land in Rhode Island that has two barns, one was built circa 1850 and the other circa 1990. The 1990 barn has vertical plank siding which is nicely weathered so it looks old. Around 2014 I built new doors for it, using locally sawn 1x12 rough cut white pine. This summer I had a visitor who looked at both barns, admired the doors on the new barn and said, "Look at those boards. You can't get lumber like that any more."
"around here old wood doesn't mean it has tight rings."
That is true in a strict sense anywhere, as outlined in the tennesee.edu doc for example. But what is 'old wood' anyways?
It's always better to acknowledge the complexities: of land use history, of ecology, of wood science, of geographic and other dissimilarities, etc. In that sense, your contrary ;) notion is justified since blanket statements about wood quality as a function of time is overly simplistic. Still, it's fair to say that the conditions of pre colonial forests did—by and large—favor tighter rings and certainly clearer boards. Certainly not every board declared as old is better than every 'new' board. And 100 years may indeed not be long enough ago. It depends. I have anecdotes from my 1910's bungalow that are somewhat opposite yours (tight grained wood) but that is just an anecdote. Perhaps there was simply less demand for select wood and so the Craftsman bungalow was afforded it vs many houses today that instead have paint grade lumber with giant knots hidden beneath.
Here's a simple but interesting story of forest history in New England:
https://harvardforest.fas.harvard.edu/diorama-series/landscape-history-central-new-england
"The peak of deforestation and agricultural activity across most of New England occurred from 1830 to 1880. Across much of New England, 60 to 80 percent of the land was cleared for pasture, tillage, orchards and buildings. Small remaining areas of woodland were subjected to frequent cuttings for lumber and fuel.
Time period:
1830 A.D.
---
Beginning in the mid-1800s and continuing for more than a century, farming declined on a broad scale across New England. Abandoned pastures and fields rapidly developed into forests. In central Massachusetts and across much of central New England these forests were dominated by white pines.
Time period:
1850 A.D.
---
As the "old-field" stands of white pine reached middle age, it became evident that they contained a valuable and rapidly growing crop of second-growth timber. As this white pine became marketable portable sawmills appeared across central New England. One of the most common and valuable uses of these pines was for "box boards" used to make shipping containers prior to the development of corrugated cardboard in the 1930s.
Time period:
1910 A.D.
---
Clear-cutting of the "old-field" white pines led to the succession of mixed hardwoods across much of the landscape. The inability of white pine to sprout after being cut, in contrast to the prolific sprouting of our hardwood species, facilitated this succession. Patterns of succession enhanced the diversity of forest types, providing a wide range of wildlife habitats.
Time period:
1915 A.D.
---
One of the characteristic features of the hardwood forest that developed after the clear-cutting of the "old-field" white pines is the predominance of multi-stemmed sprout clumps. Fast-growing species that sprout prolifically -- red oak, red maple, white ash, birches, and black cherry -- are strongly represented. Red oaks are just beginning to overtop the other trees in this view.
Time period:
1930 A.D.
---
In the period since the dioramas were constructed, the trends in forest development illustrated in the 1930 model have continued. Remarkable expanses of maturing forest extend across a densely populated landscape in the northeastern United States.
As these forests grow and mature and as dead and decaying wood accumulates on the ground, the forest landscape becomes increasingly natural in appearance and character. With time, too, early successional species decline and more shade-tolerant and long-lived species increase. Still, the legacy of land-use history persists in the distribution of species and the often abrupt transition between forest types. The stonewalls serve as a constant reminder of this land-use history. "
The other thing worth remembering is that quality saw timber stock takes time to grow, and so even within large geographic regions like the North American continent, overall availability of larger saw timber has decreased over time in relation to demand, which means some people (lots of people?) inevitably end up with lesser quality stuff at hand.
When I looked into this question a few years back I was surprised to find out that plywood for exterior applications with grades like AC and CDX is made glue that is typically less toxic than the interior cabinet and veneer grades that are imported. So I mostly buy exterior to use on the interior.
I believe I have sourced the purbond before, but can't recall much about it. If not exposed to lots of moisture I wouldn't be that worried. I would check your local suppliers to see what they stock/ can order.
I also recall hearing what norm claims above. A quick search appears to confirm this, depending on specifics of course. (https://www.epa.gov/indoor-air-quality-iaq/what-should-i-know-about-formaldehyde-and-indoor-air-quality)
As far as the 'sustainable sourcing' one approach would be to seek local products rather than imported--but of course what's 'most sustainable' is complicated.
Just saw this: https://scitechdaily.com/chemists-develop-a-non-toxic-glue-for-plywood-from-glucose-and-citric-acid/
I live in Northern BC and can only speak with some confidence about our local market. The lumber quality has certainly gone downhill in the last several years. Even 10 years ago you could expect 2x10 and 2x12 to come in beautiful spruce or pine, now basically all dimensional lumber that I see (in the north) is balsam (sub alpine fir), which is less stable and not a pleasure to work with.
The pine beetle epidemic has worked its way through and the nature of our forests have changed, and the easy to log, high quality valley bottom timber is mostly gone.
We are not yet logging our second growth forests up here, maybe in the next 10 or 20 years they will be ready.
Interesting to hear the perspective from the east coast, you guys are ahead of us by hundreds of years.
I know much of the lumber in Southern BC is second cut douglas fir, which can be very nice depending on the grade. We will sometimes get fir when we special order 2x10 or 2x12 in long lengths, for rafters or similar. It is always a nice surprise to see the beautiful pink fir show up on a site.
Foresmate is a plywood manufacturer that specializes in producing E0 formaldehyde-free lightweight plywood. They prioritize environmental sustainability and the use of high-quality materials in their manufacturing processes.
https://newfores.com/products/rv-lightweight-plywood/