5 ms·

So I guess boiling and pressing will get rid of the trapped air inside wood and it won't work very well as an insulator?

nemomarx 1y ago
You probably only use this wood for the frame, or spread through the rest of the wooden structures like rebar?
- gadflyinyoureye 1y ago
  Wood used in framing has a small r value because of the air. The timber on the exterior prevents all the energy transfer. The loss of r value can be off set with two 2x4 frames. As strong as a 2x6 wall and about the same price. Added benefit is air gaps.
heywoods 1y ago
Sounds like a great candidate for decking.
HWR_14 1y ago
Probably not. But it eliminates a lot of what makes wood flammable. I wonder how it impacts the effects of humidity and time to make wood warp.
seniortaco 1y ago
Wood is already a poor insulator, so if it takes up less space and you can fit more insulation, that is better.
- dlubarov 1y ago
  Yes, but if it's a much worse insulator, the extra heat transfer through studs might be more significant? I'm not sure if it's been measured, but I imagine this densified wood would probably have at least twice the thermal conductivity of typical construction lumber, since naturally dense hardwoods already approach that. So it seems like we'd basically need to replace 2x studs with 1x studs, assuming the same stud spacing, in order to match the thermal performance of a traditional wall. I don't think this would be a dealbreaker at all though, one could always use continuous insulation instead of cavity insulation, which has a lot of benefits anyway. Maybe it can end up being a competitor to metal studs for commercial builds, at least.
  - djtango 1y ago
    Not a materials guy but would densified wood lead to such a drastic increase in thermal conductivity?
    - dlubarov 1y ago
      Air has very low thermal conductivity, so for a lot of materials, thermal conductivity is primarily a function of how much air they contain and how it's structured (ideally in tiny pockets to minimize heat transfer through convection). Like spray foams, fiberglass insulation, etc are basically designed to hold air while minimizing convection. I believe that's somewhat true of woods as well - different woods seem to range from 0.12-0.25 W/(mK) or so, which is somewhat less conductive than the underlying compounds like cellulose (0.4), thanks to the trapped air in wood. It seems like densifying wood would mitigate the insulation contribution of trapped air, causing thermal conductivity to approache that of the underlying compounds like cellulose, though I'm not sure exactly what those compounds are with their process and how close they get to that air-free extreme.
    - 8note 1y ago
      if you dont make any other changes, it will have some detectable impact, but conductivity is linear with all of conductivity, depth, and area; and the other dimensions can also be changed like the screw diameter/pitch or the dimensions of the stud. its very unlikely that this change will be an important consideration for house building or shopping though. theres simpler spots to reduce heat loss, like double paning your windows
  - zip1234 1y ago
    If this just replaces steel beams or allows more post frame construction, the walls wouldn't change. Actually, if used in post frame style construction, it would allow for more space for insulation with less thermal bridging.
  - bluGill 1y ago
    In modern construction we already put continuous insulation outside the 2x4 so that we don't have to deal with the studs and how much worse insulation they are.
- jkmcf 1y ago
  My uncle built his home from hardwood. No insulation. In sub freezing temps, you can put your hand in the wood and it isn't cold. Compared to my (poorly) insulated home, it b is significantly better.
  - bluGill 1y ago
    That isn't a good way to measure because the inside of the house is warming up the walls. Hardwood is a poor insulator, but it is an insulator. If you touch wood it will feel warm, but it still loses a lot of heat compared to a properly insulated wall.
  - Loughla 1y ago
    Are the walls solid hardwood? Is it a cabin? How thick are the walls?
  - olddustytrail 1y ago
    Hearing this reminds me of the Dara O' Briain line that American houses seem to have been built by the first two little pigs.
- jolt42 1y ago
  "poor insulator", seems like an odd statement, but it's all relative I suppose. It's certainly better than the masonry or steel that this will replace. But if you take the air pockets out of it, then it's not going to be as good, but likely better than steel.

nemomarx 1y ago

You probably only use this wood for the frame, or spread through the rest of the wooden structures like rebar?

gadflyinyoureye 1y ago
Wood used in framing has a small r value because of the air. The timber on the exterior prevents all the energy transfer. The loss of r value can be off set with two 2x4 frames. As strong as a 2x6 wall and about the same price. Added benefit is air gaps.

heywoods 1y ago

Sounds like a great candidate for decking.

HWR_14 1y ago

Probably not. But it eliminates a lot of what makes wood flammable. I wonder how it impacts the effects of humidity and time to make wood warp.

seniortaco 1y ago

Wood is already a poor insulator, so if it takes up less space and you can fit more insulation, that is better.

dlubarov 1y ago
Yes, but if it's a much worse insulator, the extra heat transfer through studs might be more significant? I'm not sure if it's been measured, but I imagine this densified wood would probably have at least twice the thermal conductivity of typical construction lumber, since naturally dense hardwoods already approach that. So it seems like we'd basically need to replace 2x studs with 1x studs, assuming the same stud spacing, in order to match the thermal performance of a traditional wall. I don't think this would be a dealbreaker at all though, one could always use continuous insulation instead of cavity insulation, which has a lot of benefits anyway. Maybe it can end up being a competitor to metal studs for commercial builds, at least.
- djtango 1y ago
  Not a materials guy but would densified wood lead to such a drastic increase in thermal conductivity?
  - dlubarov 1y ago
    Air has very low thermal conductivity, so for a lot of materials, thermal conductivity is primarily a function of how much air they contain and how it's structured (ideally in tiny pockets to minimize heat transfer through convection). Like spray foams, fiberglass insulation, etc are basically designed to hold air while minimizing convection. I believe that's somewhat true of woods as well - different woods seem to range from 0.12-0.25 W/(mK) or so, which is somewhat less conductive than the underlying compounds like cellulose (0.4), thanks to the trapped air in wood. It seems like densifying wood would mitigate the insulation contribution of trapped air, causing thermal conductivity to approache that of the underlying compounds like cellulose, though I'm not sure exactly what those compounds are with their process and how close they get to that air-free extreme.
  - 8note 1y ago
    if you dont make any other changes, it will have some detectable impact, but conductivity is linear with all of conductivity, depth, and area; and the other dimensions can also be changed like the screw diameter/pitch or the dimensions of the stud. its very unlikely that this change will be an important consideration for house building or shopping though. theres simpler spots to reduce heat loss, like double paning your windows
- zip1234 1y ago
  If this just replaces steel beams or allows more post frame construction, the walls wouldn't change. Actually, if used in post frame style construction, it would allow for more space for insulation with less thermal bridging.
- bluGill 1y ago
  In modern construction we already put continuous insulation outside the 2x4 so that we don't have to deal with the studs and how much worse insulation they are.
jkmcf 1y ago
My uncle built his home from hardwood. No insulation. In sub freezing temps, you can put your hand in the wood and it isn't cold. Compared to my (poorly) insulated home, it b is significantly better.
- bluGill 1y ago
  That isn't a good way to measure because the inside of the house is warming up the walls. Hardwood is a poor insulator, but it is an insulator. If you touch wood it will feel warm, but it still loses a lot of heat compared to a properly insulated wall.
- Loughla 1y ago
  Are the walls solid hardwood? Is it a cabin? How thick are the walls?
- olddustytrail 1y ago
  Hearing this reminds me of the Dara O' Briain line that American houses seem to have been built by the first two little pigs.
jolt42 1y ago
"poor insulator", seems like an odd statement, but it's all relative I suppose. It's certainly better than the masonry or steel that this will replace. But if you take the air pockets out of it, then it's not going to be as good, but likely better than steel.