any experience of hemp-lime plaster or hemp board?

[tycarregydwr]

We had a good meeting with a conservation builder today, I will post more about this once we've spoken to one of two more and I have a whole list of questions!
In the meantime just for starters, has anyone used hemp materials, either lime plaster with hemp, or hemp board? I assume these are not 'traditional' (although since hemp has a long history of cultivation for fibre, maybe?), but this guy said it is a wonderful insulator and he uses it a lot.

 

[TheForge]

Yep. Have tried it on a few of our walls. Easy enough to apply, hemp isn't too expensive if you buy the shiv from source and not through a 'conservation supplier' who put hefty mark ups on. Can either mix it lime/hemp with no aggregate or lime/aggregate/hemp. It seems popular in Ireland.

As for the effect not sure as a plaster you get much insulative effect unless it's very thick. But every little helps. Still got a couple of pallets of coarse and fine hemp in our forge waiting to use.

Bit tricky to get a smooth finish, the coarse hemp looks like woodchip, the finer stuff a little rough but you can always skim over with a lime and sand top coat.

I bought the hemp direct from a farm in Yorkshire owned by the Voase family. If you google them they have a website.

 

[middi]

My experience of "hemp" usage is limited to few people I know.
They say it is not difficult to obtain and easy to use.
( It must be, some of them are still smoking it )

Middi

 

[JohnB]

The difficult to obtain stuff is due to it being illegal to grow without a licence, thanks to the people who smoke it! Otherwise anyone with access to an acre or so could grow their own building materials.

 

[Keith Bowman]

The difficult to obtain stuff is due to it being illegal to grow without a licence, thanks to the people who smoke it! Otherwise anyone with access to an acre or so could grow their own building materials.

The odd thing is that back in Tudor times, you could be fined for not growing hemp! (It was needed for ropes etc for the navy.)

 

[skier-hughes]

Our lime plasterer used hemp in the kitchen, but then said they prefered not to anymore as they'd had some bad feedback. Not sure our kitchen has benefitted form the hemp in the first two costs and we haven't had any problems with our walls.

 

[tycarregydwr]

thank you. sounds like a lot more research is needed (for a change!)

 

[Zebra]

I do have somewhere a comparison of the U-values, or R-values of lime hemp compared to other insulation materials. Just had a rummage, no luck so far, but will rummage further if you're interested. I bought mine from Ty-Mawr in Brecon, after doing the lime plastering course with them. They're very useful if you want to find out more. I have used it as a base coat on laths, not specifically for its insulation values as because it's easy to use, and has a lot of flex even once set.

 

[tycarregydwr]

Zebra, that's a helpful insight, thank you. Please don't bother searching for that info just yet, I'm not at that sort of stage of specifics yet! Perhaps once we've done one of the courses... whenever we might get around to that :roll:

 

[MdB]

http://www.cornishlime.co.uk/articles/HempforBuilding.php

 

[lou]

Hi there - I realise this is very late and you might already have made a decision but I thought I'd share my experience of hemp plaster in case it's helpful. It has to go on very thickly indeed to make any difference to the U values and, from what I remember reading on the Green Building Forum (maybe?), it's just better than nothing but not a brilliant insulator. The thickness you need to make a difference is about 60-70mm so it takes ages to dry out. In some parts of our house it is still not dry after a year, though admittedly the weather hasn't helped! The shower room wall has been so slow to dry that it's now covered in mould and I'm not sure what I'm going to do about it. Back to Ty Mawr Lime for some advice I suppose.

Additionally, we got into a very heated debate with our builder about the finish because I was expecting a much finer finish than we finally got and, to me anyway, much of it looks like 70's woodchip. I'm not very happy with it. Our conservation officer however, thought it looked fine. We compromised on the very oldest part of the building which now has a smooth finish which I much prefer. Make sure you are absolutely clear about the finish with whoever does the work before they begin or give you a quote.

Good luck!

 

[tycarregydwr]

thank you lou. I am :lol: at the thought that I might have made any decisions by now... we are still so far from making even the most basic of decisions, I'm sure we won't get to this level for many, many months. So your input is helpful and certainly appreciated.

At this stage my feeling is that we really don't care that much about the finish - though of course feelings might change if we ever get to a stage of approaching 'finish'. At the moment it's hard to imagine caring about that, when we've got bare walls, bare concrete floors, and no ceilings, etc!

I think we were most interested by the hemp-board, which sounded like potentially a quick and cheap alternative way to do things that is much more eco-friendly than normal plaster board... but more investigation definitely needed.

 

[skier-hughes]

We had two coats of hemp lime and then a top coat of normal lime which gave us a nice smooth finish.