James Ellison

Sorry meant to say 650mm walls.

Hi Jay,

That's great.

I'm not sure exactly what materials I will be using for the stem wall (will have to see what is available), probably brick for the walls with lime (NHL5) with Leca as the insulation.

I did some lime plastering at the weekend, seems quite easy actually.

I am not sure what you mean Jay by "Are you going to have a stone course for the stem wall plaster in cobb?"

I was planning on 600mm walls with no tapering. As I underdstand the only reason for tapering is to save on cob and would prefer the extra thermal mass.

I am planning on a green shed roof, to keep it nice and simple.

Just started to design it in google sketch which I will be more than happy to share.

Here is my initial design, seems very small now

Best Regards
James Ellison

Hi Jay,

Sorry for the late reply, I have been away for the past week.

Here are the answers to your questions.

1/2. It is not in a desert Environment, it is in the mountains in Bulgaria, in the Rose Valley.

3, I am quite new to cobbing but have done a couple of courses and feel confident to start building.

4, Not exactly sure of the date of the original building but only the back wall which is made of stone will be staying as the current side walls are made from adobe bricks which need renewing (cob walls will be used instead)

5, I will try to find out about the concrete foundations as I have a architect friend who helped me to purchase this and knows her stuff. I will let you know.

My main concern was whether you can actually build a stem wall directly onto the concrete as I have heard some people say the stem/cob walls all need to breathe and with concrete I may have problems with rising damp entering the stem wall as it will not have the usual rubble trench. Although after cobbing for the last 4 days with a group, the instructor did say I shouldn't have a problem doing it this way. What are your thoughts on this please?

Again, thanks for helping me on this Jay.

Best Regards
James

Hello Jay,

Thank you for your reply.

Here are a few photos as requested. Basically the back and right side wall of the existing house will be kept and I was hoping to cob further out and extend the front all the way along the exiting concrete. The stem would will hopefully be made from existing rock from another building directly on top of the concrete.

I hope you can make sense of these.

Best Regards
James

Hi All,

Looking to build my first cob house this year on a existing building plot which basically already has a solid concrete foundation.

My question is, is a rubble trench necessary if existing foundations already exist.

So, Can I build a stem wall straight on top of a concrete foundations and then the cob onto that? I have been told the stem wall is required to let the cob walls 'breathe'

Thanks in advance for any help on this as thius would make my project alot easier as there is ALOT of concrete to get rid of if not.

Best Regards
James