Milo O'Shea

Thanks for another detailed response, Terry, much appreciated.

OK to answer the easy questions first, if you can guess I'm in the UK so codes are different though I expect many of the principles are the same. My particular region is starting to incorporate eco building techniques into building regs and planning so while a few things are still grey areas there are a few materials that are being approved more readily, including lime. Lime is abundant and easily available in my area, cheap and rated very low carbon.

My anchoring plan was to use 3/4" steel threaded bar rather than iron rebar for durability.

My plot is not on unstable ground according to the relevant geological surveys, wind speed is 22 m/s (think that is metres/ second) and regs don't require seismic activity to be taken into account, probably because we have so very little.

I was thinking to use NHL5 as the lime component to replace cement in the concrete and use leca or similar as the aggregate. As I said before it's mainly a case of maximising breathability for the straw bale infill which I don't think cement based concrete will do. I've looked at a few lime-based foundation designs that have been approved by regs in the UK, but none so far that specifically form piers/ plinths. Also I'm finding it hard to find any tables outlining limecrete compression strength with any specificity. I found some for hempcrete, though I don't have much access to hemp!

I'll go back to the regs and take another look, and also I'll take a look at Geoployner cements as I had completely overlooked that.

cheers, M

Thanks for the reply, Terry.

I can't say for sure what the compression strength of limecrete will be, though I have looked at different guidance from limecrete companies (either supplying limecrete for you to mix or pouring it for you) that say a slab would be as strong as a concrete slab so I didn't think there would be that much in it- interested to know more, though?

Also, I'm not looking to pour a whole slab if possible. What I'm hoping to do is to closely mimic something like a "swift plinth" this is a ready made concrete plinth- (I haven't linked out to it's webpage as i'm not trying to promote them!) The main issue I have is that I want to lift the structure so I can use straw bales, and I also want to use breathable materials again to protect the bales from moisture and allow moisture out of the bales over time.

In my area there is a presumption in favour of low or zero carbon building which incentivises using products with lower embodied energy where possible, hence my thinking to avoid concrete.

cheers. M

Hi All,

First off hello I am a new member on this forum, though i have enjoyed reading it for some time.

I have started a building project recently and have been scouring the internet for guidance. Having already built a small shack using roundwood posts partially buried (with some shifting over time but not major) I want this project (which is bigger) to seem a bit more solid and am thinking about foundations. The design is roughly a 20 x 36 ft rectangle, with loadbearing posts at 4ft intervals which will then be infilled with straw bales. At this stage I am thinking about pier/ pad foundations to fix each post to. Ideally I would use limecrete. I'm also thinking about how and whether to brace the posts at the bottom, as well as to lift the first layer of bales

Has anyone got an opinion on this plan or could even point me in the direction of some guidance about how to form pads with limecrete please? I have seen ready made concrete pads for sale and they don't look complicated. The plot is excavated down to shale and i have drained the whole terrace, so this should be a good bearing soil.

Any advice much appreciated.

cheers M