Hempcrete Extension E17: Floor

[@paulhorn6233]

love your channel! extremely helpful informations and try outs combined with a lot of "interesting" humor! I personally do not like holes in walls, boards, layers etc. cause vapor is not a fluid. vapor pressure is regularly distributed over the entire surface, i.e. the entire surface is moistened. you often see holes in damp masonry in older houses, but the drying effect is only localized. to remove moisture, you would need rear ventilation, i.e. air circulation instead of stagnant air. nevertheless, i believe that in your case the whole thing will work. sorry to be a smart aleck. just some feedback.

[@ryanbarnes8301]

Ingenious ❤️🌲

[@homofaber3076]

:)

[@ryanbarnes8301]

Have you to do you do this as a job? I think there is a huge call for this type of work in the uk…

[@homofaber3076]

@@ryanbarnes8301 Hi - this is the first one of these I've done, But yes, there is going to have to be a lot of retrofitting floors in Victorian buildings with insulation (and maybe heating pipes) and it will make a big difference if it's done with sustainable materials. That's kinda why i was interested in trying these out. (There's also a problem with non-breathable modern materials actually damaging older structures when they are retro-fitted, 'cos they trap moisture.)

[@michaelhunt2222]

This is helpful for architecture students, thanks for sharing! Can I ask, how durable is it? Will it crumble over time as an internal wall? Is it easy to damage?

[@homofaber3076]

Hey - yes I have had architects pick my brains in a few conversions, direct experience of it is useful. Hempcrete should last indefinitely unless something goes wrong. (it's basically a standardized modern version of ancient building techniques). If it's finished in lime plaster/render or membrane and cladding it last like any wall. There are a few projects where the raw hempcrete is used as a look to the internal walls, presumably they would need to be sealed with something (breathable) because it would otherwise be a bit dusty. It's quite solid once its cured, and it looks cool, but it would show marks where it got bashed. You can also obviously see that layers it was laid in, if it was mixed and placed onsite. Or did you mean cork? In which case, it is also quite durable, springy, slightly dusty. If you bashed it hard it would mark, doesn't crumble that easily. If you search you can also find cork panels with amazing designs pressed into them, made to be used as a finish.

[@aaronvanhoucke2065]

You could have just fillt the crawlspace with sea shels. They stop capilarity

[@Ascendix_Todd]

Why not hempcrete in the floor space as well? Too heavy? More expensive than cork?

[@homofaber3076]

No, hempcrete in the floor space as well is actually the preferred option, because it's easy to seal up all the gaps and complete the thermal envelope, and it would be quite fast. It's not too heavy (and you can place it less densely between joists where it doesn't have to hold itself up), it would be a bit cheaper than cork. It acts as a wood preserver and rodents don't like it. (You would still have to find a way to complete the air tight envelope underneath it tho). The main reason here is that I had a height restriction above, and an underfloor level to match below, so there was a restriction on how deep I could make the floor wedge; and I've put a lot of glass in the building so the floor had to meet a high U-value. Cork or fleece performs better than hempcrete thermally, and I didn't have enough space to make up that thermal value in the floor using hempcrete. Then i thought I may as well use the cork as a support for underfloor pipes as well. (I guess hempcrete would be ok as a support for pipes in another situation. Thanks for asking!