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My house has some LSL (Laminated Strand Lumber) beams which, like CLT, are engineered, but are built up from wood strands of and a lot of glue instead of from b

by danans 7y ago

My house has some LSL (Laminated Strand Lumber) beams which, like CLT, are engineered, but are built up from wood strands of and a lot of glue instead of from boards like CLT. As a result, they can be made from the remainder products of milling lumber. They can even be made from rapidly harvestable plans like bamboo: https://www.sciencedirect.com/science/article/pii/S0950061815001117 https://www.sciencedirect.com/science/article/pii/S095006181... This company appears to be making them: https://www.moso.eu/en/products/bamboo-beam-panel-veneer/bamboo-beams https://www.moso.eu/en/products/bamboo-beam-panel-veneer/bam...

hammock 7y ago
Where does that glue come from and how good is it for humans/the environment?
- jpollock 7y ago
  a more important question is what happens when it's exposed to water, either through flooding or a leaky building.
  - bdamm 7y ago
    There are many forms of fungi (mold, various rot) that can feed on wet wood. There are not many forms of fungi that can feed on cured adhesive, which also functions to prevent the wood that is there from getting wet. Thus, I'd expect engineered/laminated timber to be better at repelling rot than standard untreated timber. Done well, it could last longer than steel.
    - ethbro 7y ago
      If anyone on HN has never hoisted an LVL beam (or even glulam), I would highly recommend it. Suffice to say they're 'quite a bit' heavier than wood. That weight is the adhesive and/or compression. So we're very much not talking about 'tree wood' at this point.
  - analog31 7y ago
    It depends on how the material is designed. Some materials like commonly available particle board, can't get wet at all. They swell up and crumble. On the other hand there are grades of plywood that are rated for wet applications.
- cardiffspaceman 7y ago
  I found this FAQ [1]. According to my reading of it, VOCs and formaldehyde are not a problem. [1] https://research.cnr.ncsu.edu/blogs/clt-panels/home/ https://research.cnr.ncsu.edu/blogs/clt-panels/home/
- danans 7y ago
  This is the primary adhesive used: https://en.m.wikipedia.org/wiki/Phenol_formaldehyde_resin https://en.m.wikipedia.org/wiki/Phenol_formaldehyde_resin

by danans 7y ago

hammock 7y ago

Where does that glue come from and how good is it for humans/the environment?

jpollock 7y ago
a more important question is what happens when it's exposed to water, either through flooding or a leaky building.
- bdamm 7y ago
  There are many forms of fungi (mold, various rot) that can feed on wet wood. There are not many forms of fungi that can feed on cured adhesive, which also functions to prevent the wood that is there from getting wet. Thus, I'd expect engineered/laminated timber to be better at repelling rot than standard untreated timber. Done well, it could last longer than steel.
  - ethbro 7y ago
    If anyone on HN has never hoisted an LVL beam (or even glulam), I would highly recommend it. Suffice to say they're 'quite a bit' heavier than wood. That weight is the adhesive and/or compression. So we're very much not talking about 'tree wood' at this point.
- analog31 7y ago
  It depends on how the material is designed. Some materials like commonly available particle board, can't get wet at all. They swell up and crumble. On the other hand there are grades of plywood that are rated for wet applications.
cardiffspaceman 7y ago
I found this FAQ [1]. According to my reading of it, VOCs and formaldehyde are not a problem. [1] https://research.cnr.ncsu.edu/blogs/clt-panels/home/ https://research.cnr.ncsu.edu/blogs/clt-panels/home/
danans 7y ago
This is the primary adhesive used: https://en.m.wikipedia.org/wiki/Phenol_formaldehyde_resin https://en.m.wikipedia.org/wiki/Phenol_formaldehyde_resin