navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Hemp insulation for granite house in Haute Correze?  (Read 430 times)
Le Hobbit
Jr. Member
**
Offline Offline

Posts: 65


« on: July 26, 2020, 08:07:33 PM »

Hello all. We are in the process of buying an old house of about 170m2 over two floors in the Haute Correze in the Massif Central in Central France. We live here full time and have been looking for a secluded property with large land for several years now. We wanted a place we could eco renovate and make our own, rather than buying something already done with non eco materials. The house is not a complete wreck but much of the work the French owners have done is of very poor quality or has compromised the breathability of the building. It's only been an occasional holiday home. We will rip everything out and start again.

The house sits at a quite high altitude for Central France of 810 metres asl (2657 feet in old money!) but it is south facing and has a wooded hillside behind and to the west so it is pretty sheltered from cold winds. There are also large oaks on the eastern side of the land giving shelter from cold easterlies.

As is common here it is made of granite and partly built into the hillside. The rear wall of the ground floor is below ground level with all windows on the south facing aspect apart from one on the west facing gable end.

Our previous house that we renovated was done mainly with drylining and plasterboard but we despise the stuff with a vengeance and old houses lose so much character when drylined with smooth, flat plasterboard.

So alternatively we plan to use hemp lime which is popular here in France as an internal 80mm render on the stone walls to greatly improve the insulation value of the 500mm thick walls. This will be finished off with lime plaster. 

We will also create internal dividing walls using wooden stud work and hemp-lime infill with shuttering. For the rear north facing wall which is below ground level on the first level there are signs of damp penetration in the wall. A builder who viewed the property with us advised that a lack of guttering on the roof, combined with no drainage behind the house has caused the issue. Also the stone work has been pointed with cement externally so this needs to be removed and repointed with lime to help the building breathe. We will also be having a new steel standing seam roof with bonded PIR insulation and new guttering and all rain water will be directed into the well/tanks.

We wish to use 600mm x 300mm x 90mm hemp preformed blocks to construct an internal rear second wall with an air gap behind. The manufacturer of the blocks has said there cannot be an air gap and we must fill the void with a loose mixture of hemp lime as the wall is constructed? This seems weird logic to me? Surely there needs to be an air gap, so that any residual damp in the rear wall cannot penetrate into the hemp blocks?

They also advised that the first layer of the hemp blocks must be laid on a damp proof membrane strip and not directly onto the existing concrete floor. This is to avoid capillary action through the blocks. Any thoughts on our project and advice on using hemp lime and preformed blocks? Cheers LeHobbit.
Logged
offthegridandy
Hero Member
*****
Offline Offline

Posts: 1008



« Reply #1 on: July 26, 2020, 08:23:17 PM »

Hi Hobbit, sounds like a wonderful vision you have; I wish you well.

Although I have used a number of lime products in our barn high in the Welsh hills I would hesitate to offer advice.  But I CAN point you towards an expert with many years experience.  Get in touch with a guy called Nigel  Gervais at Ty Mawr lime https://www.lime.org.uk.  I've known him since 1985 and his knowledge is extensive . His tel nos is  01874 611350 you may get his wife Joyce or a member of staff but if Lime is your  game then these are the people to ask.

Good luck.

Andy

Please don't forget those photies
Logged

8 KVA Lister TS2 Startamatic Genny
24 Volt 1000amp battery bank
Outback VFX3024
4.6 Kw PV array ground mounted
Outback Flexmax 80
2 X Flexmax 30 PV CC
2.5 Kw WT H Piggot design 4.5 Mtr Dia AC coupled
12 Mtr free standing Tower.
u/floor heating from oil boiler cross linked to 12 K wood stove
Le Hobbit
Jr. Member
**
Offline Offline

Posts: 65


« Reply #2 on: July 27, 2020, 04:08:55 PM »

Hi Hobbit, sounds like a wonderful vision you have; I wish you well.

Although I have used a number of lime products in our barn high in the Welsh hills I would hesitate to offer advice.  But I CAN point you towards an expert with many years experience.  Get in touch with a guy called Nigel  Gervais at Ty Mawr lime https://www.lime.org.uk.  I've known him since 1985 and his knowledge is extensive . His tel nos is  01874 611350 you may get his wife Joyce or a member of staff but if Lime is your  game then these are the people to ask.

Good luck.

Andy

Please don't forget those photies

Thank you for the reply. I will contact them, but probably by email.
Logged
renewablejohn
Hero Member
*****
Offline Offline

Posts: 2963



« Reply #3 on: July 27, 2020, 08:36:29 PM »

If your going to use lime than another plus for Ty Mawr although I would suggest going on one of there Lime Mortar and Lime Plaster courses.  I went on a course there prior to renovating my old stone farmhouse and its the best money I have ever spent. I am now after several years an expert in using Lime and will never go back to using cement. Its brilliant stuff but you do need to know how to mix it properly and remember you only have a 6 month period during which you can use it. You certainly have the right idea of getting the house to breathe. Mine was damp all over the place but with large areas pointed with cement. After raking out the cement and repointing with Lime Mortar the damp just disappeared.
Logged
Le Hobbit
Jr. Member
**
Offline Offline

Posts: 65


« Reply #4 on: July 28, 2020, 06:34:38 PM »

If your going to use lime than another plus for Ty Mawr although I would suggest going on one of there Lime Mortar and Lime Plaster courses.  I went on a course there prior to renovating my old stone farmhouse and its the best money I have ever spent. I am now after several years an expert in using Lime and will never go back to using cement. Its brilliant stuff but you do need to know how to mix it properly and remember you only have a 6 month period during which you can use it. You certainly have the right idea of getting the house to breathe. Mine was damp all over the place but with large areas pointed with cement. After raking out the cement and repointing with Lime Mortar the damp just disappeared.

Yes Ty Mawr are great. We are unlikely to get back to the UK for one of their courses but we have done lots of lime pointing before in our last Charente renovation in France. It's very exciting, especially when adding hemp to the mix as that is the magic ingredient for insulation. We will even be making a 28m2 floor slab from hemp lime in the current stable which will be converted into a snug.
Logged
renewablejohn
Hero Member
*****
Offline Offline

Posts: 2963



« Reply #5 on: July 29, 2020, 08:13:49 PM »

For the floor slab have a word with Ty Mawr with respect to the foamed glass insulation.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!