Transition Culture

An Evolving Exploration into the Head, Heart and Hands of Energy Descent

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29 Sep 2008

Hemp Lime Plastering my Kitchen

We knew it was time to do something to address the energy inefficiency of our kitchen when energy-in-buildings expert Rob Scott McLeod was doing an energy efficiency makeover plan for our house in January, and he put his hand on our kitchen floor and said “touch the floor… now put your hand in the fridge” – the floor was colder.  It used to be a garage, so the roof is uninsulated, and the floor is clay tiles laid onto an uninsulated concrete slab.  The cavity in the walls is uninsulated. So, all in all, a freezing kitchen, impossible to raise to any tolerable temperature.  With winter looming once again, it was time to sort it out.  Over the next few days I will tell you about what we did, but having just spent a couple of days hemp and lime plastering, I want to wax lyrical about that.

I love hemp and lime plaster. If you are used to plastering with normal plaster, hemp and lime is odd stuff.  It is a bit like trying to plaster with tuna and mayonnaise. What it produces is a wonderfully soft, warmand sculptural plaster.  It is wonderful for taking the square edges off right angles and corners, and for breathing some beauty back into unloveable spaces.

When I was in Ireland I knew a few places to get hemp for construction, but in England it took a bit more looking for.  In the end I got it from the Cornish Lime Company, who were very helpful and who got it to me pretty quick.  Because I had rather left it to the last minute I didn’t have time to find a cheaper way of doing it, which would have consisted of finding a source for agricultural lime or more locally grown  hemp…   Using agricultural lime greatly reduces the amount of hydraulic lime you need to buy in.  Provided you have some kind of trailer to go and collect it in, agricultural lime is dirt cheap.

The recipe for hemp/lime plaster I used to use in Ireland replaced a lot of the expensive lime with agricultural stuff;

  • 1/6th bucket of NHL 3.5 hydraulic lime
  • ¾ bucket hydrated lime (i.e. White Rhino)
  • ½ bucket ground limestone (the kind farmers use on their fields, dead cheap…)
  • 1¼ bucket of water

Mix to a slurry, then add 1 and 2/3rds bucket of hemp.

When I rang Cornish Lime to ask for recipes for hemp/lime using the stuff I got from them (NHL 2 lime and dried, chipped hemp), they directed me to the website of St Astier, and to their fact sheet on hemp building.  This was very informative, however I always get a bit fed up with mix recipes that refer to 200 litres of hemp and so on, I want to know how many buckets of this and that.  Much easier.  So, after a bit of fiddling about and experimentation, here is the recipe that worked for me, and which made a gorgeous sticky plaster which went on lovely…

  • 2 buckets of water
  • 3 buckets of NHL2 hydraulic lime
  • 4 buckets of dry shredded hemp.

Gorgeous.  When you mix it in a mixer, you put the water in first, then the lime (watch out for that lime dust, horrible stuff…), then the hemp. Wet the wall first, and then apply the hemp.  Getting hemp to stick to the wall is not like normal plaster.  You kind of press it onto the wall, takes a bit of practice, but once it is stuck to the wall you can then add to it or smooth it.  You can get various finishes to it, from the rough to the very smooth.  I tend to like it being smooth, you do that by waiting until it has been on the wall for 30 minutes to an hour, and then go over it with a rubber glove on and rub it vigorously.  The final result is worth the effort.

You can put it on at various thicknesses.  I put on about 2 inches, but in a couple of weeks I intend to do our porch bit, and it will go on a lot thicker there….  fabulous stuff.  Thanks to Rowan (my eldest) and his mates Sam and Alex who helped, and also to Sky and Robert for their help too.

Categories: Natural Building

Comments are now closed on this site, please visit Rob Hopkins' blog at Transition Network to read new posts and take part in discussions.


29 Sep 4:03pm

Hi Rob,

What a great and useful post! This is exactly the kind of thing we need to be doing for the back (cold) walls of our apartment. Apart from the challenge of figuring out how to translate the ingredients into French, I do have a few more questions, such as:

-whether a half-inch or one-inch layer gives any significant insulation
-how long it takes to dry
-whether you can paint the resulting surface

If you have a website or something to direct me to, rather than going into all the detail yourself, that’s fine, too.

Thanks, and happy, warmer winter!

Corinne in Paris

Josef Davies-Coates
29 Sep 5:26pm

Great useful post.

We need a lot more howto stuff like this.

In fact, what we need is something like this:



Steve Blaes
1 Oct 2:44am

That is an incredible idea, I too am also curious about the insulative properties of this plastering technique… I am familiar with gypsum and lime but the use of hemp is not all that prevalent or available here in the states. I very much would like to experiment with this concept though!

chris hayes
2 Oct 10:48pm

Good to get a recipe by the bucket! Any ideas on what the ratio’s would be for a hemp-lime mix that would be poured into a timber frame-shuttering it as you moved up the wall?

3 Oct 9:51am

Chris, you will find the recipes for wall mixes in the fact sheet linked to in the article…
All the best

2 Nov 9:59am

Hemp Bricks can be made that are lighter and stronger then normal bricks.

The world is insane if we dont get over cannabis prohibition.

Its the best renewable resource and the only plant that gives a complete amino acid protein…..

8 Nov 8:46am

hi Rob
I have an old house in Ireland which I hope to renovate and came across your blog while looking for suppliers of hemp hurds. Can you please help?
Also where did you get NHL 3.5 hydraulic lime?
Nice blog btw.

8 Nov 11:35am

Hi Errigal
I used to buy mine, when I lived in Ireland, from Steve Allin at Hemp Building (, or you could also get it from Hempire ( Lime? I used to get it from Loch Place near Bandon, but there are a few other people who do it now too, but I can’t remember the names….
Best of luck with your hemp plastering!

8 Nov 7:26pm


Great simple way to add a tad of insulation, along with art work. This comment is about the use of lime:
I personally tend to only use it for the exterior, where it works as GoreTex. Interior I prefer an earthen plaster, and I add straw from any grain as well as hemp, depending what I have handy; (presently have 2,5 hectares of hemp!)…in order to gain insulation and/or sculptural effect.
Earthen plasters are simply earth in the right balance between sand and clay, you got to make a few sample smears and let them dry to know what mix you have in your own soil. You may have to buy fine sand, perhaps look for some clay.

The advantage to using earth plaster is better breathable walls, and more local, free low-energy products.

The disadvantage is that it takes longer time to dry, and during the time is not good to live in the rooms due to humidity. Such plaster also isn’t as ‘hard’ to the touch as lime plaster, however a slight whey based spray will solve this, while still leaving the wall porous…

Thank you for a great intiative and blog,

Max Vittrup Jensen, PermaLot Centre of Natural Building (Czech Republic)

29 Mar 1:12pm

just the type of blog i had been looking for. what type of mixer did you use when mixing the plaster? is it possible to overmix the plaster for too long? did you have any difficulties applying to plasterboard, particularly on the ceiling?