What would you say if you were told that there is a type of insulation made from a renewable resource that performs well and is both water resistant and vapor-open? Plus, it doesn’t make you itch, it has zero VOCs, and it has an exceptionally low carbon footprint compared to other insulation materials. You may have heard of wood-fiber insulation board—also called low-density fiber board (LDF)—but you probably haven’t used it yet. Maybe you should.
The product was first produced in Europe in the 1930s, but it wasn’t until the mid 1990s that it started to penetrate the market. Since that time, it has grown to become a small but significant part of the insulation market, and is starting to gain ground with environmentally-conscious designers and builders in North America.
Wood-fiber board makes use of softwood residual timber, and in Europe it competes with extruded polystyrene (EPS) rigid-foam insulation in price and performance. The imported products available in North America sell at a higher price point, but they are arguably within reason if you consider their features and benefits. Also, costs could drop if they were to be manufactured domestically. Currently, there is at least one company—Maine based GO Lab—looking to build a manufacturing plant in the U.S.
Wood-fiber insulation and cellulose insulation are made from the same raw material, but cellulose is newspaper, whereas wood fiber comes from softwood chips. According to GO Lab president Josh Henry and marketing director Matthew McConnell, the company is gearing up to produce wood-fiber insulation in a former paper mill in Madison, Maine. They describe the process of making it as similar to making paper. There are two ways to do it—the dry method and the wet method—and each results in a product with different…
Get building science and energy efficiency advice, plus special offers, in your inbox.
This article is only available to GBA Prime Members
Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.Start Free Trial
Already a member? Log in
How's the termite resistance?
There is nothing in the rigid board product to repel termites. Nor is there in most insulation; other measures are recommended to resist pests. Loose-blown wood fiber, like cellulose insulation, has a borate additive for fire resistance that is also an insect deterrent.
Rockwool is not termite or insect/mice friendly at all
Rockwool is certainly less rodent friendly than fibreglass, but I found mouse nests in batts of Rockwool I left stacked on a crawlspace floor over the winter. It may not be their preferred choice, but they aren't repelled by it either.
Doug, I have to disagree as well--I have a pile of Roxul in my barn and rodents seem to love it. It makes excellent nesting material, like fiberglass. They can't eat it, nor can insects, but there is a difference between insulation vendors proclaiming their product "does not have food value" and having pests actually nest or tunnel in it.
Gentlemen- i am disappointed to hear your experiences with mice - perhaps the optimum insulating approach then to discourage mice is very tight house and no batts or blown in insulation regardless of material ?
I think the best strategy is exclusion. A building envelope detailed to exclude rodents makes the insulation choices much less important.
My own house is about 25 years old and we have never had mice in it, although I know they are thick on the ground, as our cat brings them in his pet door frequently.
Please make the case for wood fiber versus the denser form s of mineral wool ?
I think what you are looking for is in the first paragraph, "it has an exceptionally low carbon footprint compared to other insulation materials." For all the advantages of mineral wool (and I love the stuff), making it is fairly energy intensive.
Doug, if you're looking for high levels of fire resistance, or if you need the highest R-per-inch rating without using foamed plastic, or if it will be used in a location with very high moisture levels, mineral wool is probably a better choice. Costs vary. North American production is still in the works so the material has to be shipped from Europe, but moving large quantities by ship is much more efficient than by land.
For every other practical purpose I can think of--carbon emissions, ease of installation, etc.--rigid wood fiber board wins. Do you have a specific situation you're considering?
Michael - I am planning to build a tight house, tho am not a slave to energy savings or carbon sequestration .
1) On site formulated foam of any nature is out (if you read the toxicology literature that done by toxicologists who do not have an industry relationship -like my wife !-you’d know why!) but foam boards manufactured under factory controlled conditions are not an issue from a toxicology standpoint.
2) I am focusing only on board and batt formulations (cathedral ceilings, hot roofs etc) . While I just feel uneasy about breathing Rockwool or fiberglass blown insualtion, compared to cellulose or wood fiber , any advantage here is thus moot.
3) This will be a coastal zone 4 marine location, so that militates against wood fiber i reckon.
I am assuming rockwool is superior to woof fiber re;bulk water shedding, but that wood fiber T&G panels will let less air through
4)I am still interested in comparing the compressibility (which presumably goes down with deeper depths of either insulation),the Rockwool boards versus the paraffin impregnated wood fiber boards.
Wood fiber presents the possible opportunity to assemble a simple, breathable wall that sheds bulk water and (i believe) is a decent air barrier if taped. In Europe i believe in places they rely on the paraffin T&G taped boards to achieve their enire WRB on walls OR roofs (!)
5) A real advantage of Rockwool often overlooked it seems by GBA readers/posters is its arguably the least attractive insulation for bugs termites (and mice -important consideration I would submit if using PEX plumbing/pipe; once you remove the mice threat PEX is a clear winner !)
6) while the advantages of external below grade foundation insulation are not as critical in zone 4 vs further north, I could insulate the basement wall from exterior (and indeed use four sub slab insulation and link to external above ground insulation. And deal with rim board insulation issue without using any spray foam
I am not building in a fire prone Location, but as I going to be using truss floors and non masonry other than the foundation, i certainly can still benefit your from that advantage of rockwool.
If i were in a drier climnate brave enough to use the taped T&G wood fiber panels as my WRB and bulk water shedding on both walls and roof, this would be a no brainer. I predict this will be very successful production. In such a niche. It will be interesting also to see if peel and stock products will be certified to work over this.
Does anyone have a comment on what to do with the leftover Gutex or similar wood fiber insulation. Can it be composted??, or do the flame retardants make that impossible? Just trying to understand the whole lifecycle story of wood fiber insulation. Thanks.
Log in or become a member to post a comment.Sign up Log in