Freyja Williams

Okay great. Thanks for your reply. Given the abundance of sheep and goats around here I think wool makes sense. My concern with this is that filling a compartment in the roof with wool is likely to create good habitat for mice, who may then make a nest there. Is this likely? If so, is it as problematic as I think it is? Is there a way of getting around this? In terms of not creating habitat for food-eating little friends, ash sounds like a better option....?

To be clear, when you say filling the structure beneath the roof with pillows (I love this idea btw), I guess you mean that we would need to build a sort of false roof that would be the ceiling of the room..

Hi everyone,

My family and I are thinking about our first serious build for a communal space on our land in the semi-arid area around the city of Fundão, Portugal. I'm very keen on water capture because we have a very limited water supply and when it rains, it rains for a year (and then not again for another 7 months); plus I'm a complete amateur, so I like the idea of smooth, simple corrugated surfaces as a roofing material.

The issue that immediately arises in my mind is that corrugated metal does not offer much in the way of protection from extreme heat and cold (both of which we are blessed with). Can anyone suggest some good insulators that can be used for roofs?

Thanks,
Freyja.

Glenn Herbert wrote:Assuming your rocky slopes come with loose rocks in the soil, I would use the rocks to make the terraces. Slope the faces back, DO NOT try to make pretty vertical walls.

We do have some loose surface rocks but not enough to make the size and quantity of terraces that we need (about 1m tall x 10m long x 2 levels of terraces). Making sloped faces for the walls sounds very sensible. Thank you. Maybe we could make the earthen walls more durable by using what rocks we do have to create a stone facade for the walls to protect them more against heavy rains?

Thank you so much to both of you for your input. This has been so helpful.

Joseph Lofthouse wrote:
At my place, if water overflows a terrace it will scour out rammed earth. In my climate, earthen terraces work fine as long as overflows are constructed and lined with rocks that are larger than can be carried away by the largest flows. So at my place, rammed earth terraces have a slight bund on the edge, so that they are essentially gently sloped shallow swales. So overflow is directed towards spillways.

Given that I would like to make at least two levels of terraces, surely the spillway from the top terrace could lead into the terrace below, to make sure they both get optimum saturation (I would like to retain as much of the winter rain as I can, because in the summer there is none); similarly that terrace below could also have a spillway for when it becomes full... And then the excess from that lower terrace could go into the pond at the base of the slope... Something like that? Apologies for asking many questions - I have little experience. Insights and affirmations are very helpful.

Hi fellow permies,

My family and I have a piece of land in central inland Portugal. It is in quite a mountainous area and the land itself is one big slope with lots of smaller vallies and slopes dotted around the edges. There is a a couple of slopes in particular (one west and one north facing) that are very important in terms of water retention on our land, as the seasonal rains in the winter will simply wash down their barren rocky slopes onto the properties adjoining.

So I would like to make terraces. I have a lot of sub soil from one pond I dug at the base of one of the other vally slopes on the land, and I will dry to dig more at the bases of the west and north facing slopes as well. So I will have a wealth of soil. For this reason, I would like to use the soil in order to build my terraces but I am unsure of the best method. The idea that comes to me most readily is using the subsoil in order to make thick rammed earth walls and then filling the trough that has been created with biomass in order to create usable, deep soil.

I am unsure about some of the practicalities of this and am not having much success finding information regarding this subject online. Is it wise to build a terrace wall from rammed earth? Will it be strong enough? Will torrential seasonal rains be a problem. Should the wall be sloped at an angle, getting wider at the base, thinner at the top or can it be a standard wall dimensions? Another thing I was wondering is (assuming a rammed earth terrace is a good idea) whether I can slimply begin to build the walls onto the soil or if I should dig down to the bedrock (which is only half a foot or so down in some places) and build on that?

So many questions. Any insights valued and appreciated. Thanks.

"If is too rocky to put in Swales you can do the same thing by piling
rocks and/or wood on contour and then adding your biomass on the
downhill side. In that way it is kept in place. I have done this successfully
on a rocky, sloping piece of ground."

Thanks, this is encouraging, although I'm not sure I understand putting the biomass on the downhill side. Surely the rocks or wood would hold the biomass in place if the biomass was on the uphill side of the rocks/wood? Am I imagining this wrong? or perhaps misunderstanding the terms incorrectly.

I had originally imagined something like building a 1 meter(ish) wall/barrier type thing then filling it, making it level in order to create a level terrace composed of biomass that would become topsoil, and planting it up with herbaceous nitrogen fixers and Italian alder.

Also, does anyone have any thoughts on what sorts of mixtures of biomass would make for good in-place deep composting? Or is it more a matter of "don't worry - make it wet and airy and it'll be just fine"?

I am interested in doing something I would call deep in place composting as the soil on my land is pitifully shallow before hitting rock (over grazing by the previous owner + slopes + winter torrential rains = super erosion).

I will be trying to build above ground with subsoil banks creating a trough and then filling with biomass, woody fibrous things and canas (hollow for air release over time), with soil layered with straw and possible manure then a thinnish compost cover in order to allow for good water filtration from the beginning. But I feel very uncertain. Thoughts?