Robert Alcock

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since Mar 25, 2014
Ecological designer, self-builder, forest gardener, writer, home educator
Cantabria, N Spain
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Recent posts by Robert Alcock

Hello all,

Just to let you know I am posting up this year's version of the Natural Cycles Calendar for your delight and edification.

Unfortunately website issues mean I am no longer able to post the calendar up on our website,, for you to download it.
However, if you sign up for our quarterly newsletter then you'll get the calendar attached to that.
Happy new year to you all,


2 years ago
We are looking for an individual or couple to take care of Abrazo House, our ecological learning centre in Cantabria, northern Spain, for a minimum of 12 months to be extended by mutual agreement, starting in autumn 2017.

You will live for free in Snail Cabin, our cob cabin, including electricity, water, internet, and use of garden produce, in exchange for approximately 20 person-hours a week looking after the site, including cleaning the houses, cutting and raking the grass, cultivating and harvesting produce from the forest garden and vegetable garden, maintenance and repairs.

This is an outstanding opportunity for young people who want to get into the field of ecological education. If you wish, you will have the chance to organise ecological learning events (courses, workshops, etc.) at Abrazo House using the site facilities. It also includes the chance to earn additional income managing holiday rentals.

For more information or to apply, please visit our website.

3 years ago
Two hybrid cob-straw bale houses with roundwood post-and-beam structure and green (living) roof, with superb potential for autonomous low-impact living, each on 2200m2 of south-sloping woodland, in a small village with stunning views and excellent communications.

Each of the two houses is 60m2 with 60m2 attached workshop/garage. Each is on its own 2200m2 plot of land with outstanding views over the beautiful Aras valley, in a small village with excellent communications: 10 min from the A-8 motorway, 15 min from Laredo, 35 min from Santander, 50 min from Bilbao.

The houses are fully legal with architects’ plans and municipal and provincial permits.

The houses are located in a village with mains water and electricity at the entrance to the site, but are designed to facilitate the option of going fully off-grid.

The guide price for each house is €135,000. There is an option of interest-free payment of part of the total cost, over a time period of up to five years.

Please see for full details or to get in touch.

3 years ago
We are seeking partners to drive the next stage in the development of Abrazo House (, an ecological education project based in Cantabria, N Spain.

We are looking for a few committed, grounded people who will build on our work since 2006, and lead the transformation of Abrazo House into an economically self-sustaining project that will carry forward our vision of Learning for Earth Restoration, running bilingual programmes in English and Spanish that nourish four areas of holistic learning: Intellectual, Emotional, Spiritual and Practical.

With our help, support and guidance, you will take full responsibility for setting up and running an autonomous social enterprise based at our unique facilities in a small village near the north coast of Spain, attracting students of all ages from near and far to courses that offer the best in ecological education, while taking advantage of what our unique region has to offer the world.

This task is not for the faint-hearted. We are looking for partners who are committed to the urgent work of learning for ecological restoration, who are willing and able to do what it takes.

If you think this might be you, please read the attached pdf and get in touch via our website:

3 years ago
Hi Akua,

Good to see you're enthusiastic about cob, but a warning: cob is not necessarily the right material for a house in a humid tropical climate. You may end up with a house that is too hot and humid inside. Look at local housing methods that have stood the test of time; in many humid tropical areas these involve lightweight structures that allow the breezes to flow through...

The first rule of ecological building is to respond to the context.
4 years ago
You really want those gutters as a way to channel excess water off the roof safely. Much better to install a rainwater catchment system, plant a climber near the overflow (so it can help use the water you can't store) and then train that climber back up over your roof, doing the same job as you propose. But watch out, you'll need to clear out all the leaves or else you'll end up with plants in your gutters for sure!
4 years ago
Hi Irene

The website doesn't seem to be working anymore (or maybe it does but I can't read Dutch). Any progress to report on this project?


4 years ago
Hi Glenn

Yes, that's basically what I was getting at. Thanks for clarifying. Except that since rocks do not flow, the tyre will not have to support the whole weight of the building in tension, either. If it was a tyre full of (say) very wet sand, it would be a different story...

I would say that straw/sawdust is not an either-or issue. They do different jobs in a cob mix.

Straw (or other fibre) is for tensile strength and I would say is necessary in any cob wall.

Sawdust (or other lightweight additive) doesn't add tensile strength but improves insulation value and reduces weight, possibly at a cost in compressive strength. OTOH if you have less weight, you need less compressive strength, as much of the weight the wall needs to hold up is the wall itself.

In the wall of our cob house, we replaced half the sand with wood shavings (basically coarse sawdust) to improve insulation value. So the mix by volume was 40% clay soil, 30% sand and 30% wood shavings, plus straw -- compared with a normal mix of 40% clay soil and 60% sand that we used in the cabin we built first.

I did some basic compressive strength tests (measuring the load required to crush various bricks of each type) which indicated that the compressive strength of the sand-sawdust-clay mix was not significantly different to the normal sand-clay mix. (See photo of compressive strength test. Please note the highly sophisticated and expensive scientific equipment.)

This result was good enough for me, so we built the main wall using this mix. It's held up extremely well, is definitely warmer than standard cob, and has an added minor advantage over the standard mix, that you can drill or nail into it. Only disadvantages are that it dries more slowly and shrinks more when drying than a standard cob mix.

Good luck,


4 years ago