3 ms·

Came here to say this, I've heard it called 'glue lam' also. Who the hell thought up the mass timber name though?! That just says to me a solid (mass) of uneng

Came here to say this, I've heard it called 'glue lam' also. Who the hell thought up the mass timber name though?! That just says to me a solid (mass) of unengineered wood.

masklinn 7y ago
I guess they mean the main structural mass is timber-based? It's really odd terminology but might simply crop up from details of the field's lingo which makes no sense to outsider. Apparently CLT and gluelam are different methods of engineering wood: in CLT the boards are laminated in cross-frames (so one layer is laid north-south and the next is east-west) to improve structural resistance across non-longitudinal orientations; while for gluelam all layers have the same orientation so the end-result is closer in behaviour to regular sold timber.
- benj111 7y ago
  Yes, I would guess constructions like this make use of both gluelam and CLT.
jaggederest 7y ago
https://www.youtube.com/watch?v=4j_UjIshzMc https://www.youtube.com/watch?v=4j_UjIshzMc That's literally what it is. You can do it in all sorts of interesting different ways, but the idea is, where with other techniques you'd use e.g. insulation, gypsum wallboard, oriented strand board sheathing or plywood, instead you just... put more wood on it.
- benj111 7y ago
  There's no mention that this doesn't contain insulation etc, and does explicitly mention that glue is used. I'm not sure you could use that building technique for anything over a few stories.
  - masklinn 7y ago
    UBC's Brock Commons opened in 2017 and has 18 stories over 53m. And Mjøsa Tower was just finished (March 2019), also 18 stories but 85m. They all uses concrete though. Brock has concrete stairwell cores. Mjøsa apparently limited concrete to upper floor decks, for weighting (elevator shafts and stairwells are apparently CLT).
    - coredog64 7y ago
      AIUI, concrete is there for fire code reasons. You want the stairwell to burn last to give everyone a chance to get out.
    - benj111 7y ago
      The youtube video, and comment I was responding to talks about buildings made entirely out of wood, no glue, no insulation, no screws?, just wood. With those sorts of constraints, you're going to be limited by how high you can build.
alkonaut 7y ago
Gluelam is usually used for the older (more established) technicque of just making structural wood beams that are larger than can normally be sawn in one piece. E.g. the largest dimension of regular lumber may be 50x200mm, but you can make a 100x500 gluelam cross section by simply gluing five 100x50 on top of each other. That also has the benefit of being stronger than the individual parts because their weaknesses are averaged (much like how a spun rope works). So Gluelam beams are used as an alternative to steel beams. This more recent tech is cross-laminated-timber (CLT) where flat pieces of timber and sheathing is glued together to form large construction elements (walls, floor sections) CLT is used as an alternative to building modules. E.g. CLT can form a floor slab between storeys of a highrise, or a wall section where you would otherwise use a prefab concrete or steel/glass piece. It is true that CLT is both "glued" and "laminated" (so it is a kind of glue-lam) but using just "gluelam" was established already as short for "gluelam beam".

Came here to say this, I've heard it called 'glue lam' also. Who the hell thought up the mass timber name though?! That just says to me a solid (mass) of unengineered wood.

masklinn 7y ago

I guess they mean the main structural mass is timber-based? It's really odd terminology but might simply crop up from details of the field's lingo which makes no sense to outsider. Apparently CLT and gluelam are different methods of engineering wood: in CLT the boards are laminated in cross-frames (so one layer is laid north-south and the next is east-west) to improve structural resistance across non-longitudinal orientations; while for gluelam all layers have the same orientation so the end-result is closer in behaviour to regular sold timber.

benj111 7y ago
Yes, I would guess constructions like this make use of both gluelam and CLT.

jaggederest 7y ago

https://www.youtube.com/watch?v=4j_UjIshzMc https://www.youtube.com/watch?v=4j_UjIshzMc That's literally what it is. You can do it in all sorts of interesting different ways, but the idea is, where with other techniques you'd use e.g. insulation, gypsum wallboard, oriented strand board sheathing or plywood, instead you just... put more wood on it.

benj111 7y ago
There's no mention that this doesn't contain insulation etc, and does explicitly mention that glue is used. I'm not sure you could use that building technique for anything over a few stories.
- masklinn 7y ago
  UBC's Brock Commons opened in 2017 and has 18 stories over 53m. And Mjøsa Tower was just finished (March 2019), also 18 stories but 85m. They all uses concrete though. Brock has concrete stairwell cores. Mjøsa apparently limited concrete to upper floor decks, for weighting (elevator shafts and stairwells are apparently CLT).
  - coredog64 7y ago
    AIUI, concrete is there for fire code reasons. You want the stairwell to burn last to give everyone a chance to get out.
  - benj111 7y ago
    The youtube video, and comment I was responding to talks about buildings made entirely out of wood, no glue, no insulation, no screws?, just wood. With those sorts of constraints, you're going to be limited by how high you can build.

alkonaut 7y ago

Gluelam is usually used for the older (more established) technicque of just making structural wood beams that are larger than can normally be sawn in one piece. E.g. the largest dimension of regular lumber may be 50x200mm, but you can make a 100x500 gluelam cross section by simply gluing five 100x50 on top of each other. That also has the benefit of being stronger than the individual parts because their weaknesses are averaged (much like how a spun rope works). So Gluelam beams are used as an alternative to steel beams. This more recent tech is cross-laminated-timber (CLT) where flat pieces of timber and sheathing is glued together to form large construction elements (walls, floor sections) CLT is used as an alternative to building modules. E.g. CLT can form a floor slab between storeys of a highrise, or a wall section where you would otherwise use a prefab concrete or steel/glass piece. It is true that CLT is both "glued" and "laminated" (so it is a kind of glue-lam) but using just "gluelam" was established already as short for "gluelam beam".