projects •  Basic facilities •  Growing things
•  Building renovation •  Sanitation
•  Energy generation •  Water

Building renovation and reconstruction

Blog entries on this subject  > >

For renovations to the existing dry stone agricultural builings (built to house pigs, sheep and goats and store the produce of the quinta), we're recycling and reusing existing materials as much as possible, working with traditional building techniques - both local and from other traditions - and sourcing materials as locally as possible.

The idea is to adapt our lifestyles as much to suit the existing structures and legislation applying to them as the other way round. For more on the subject of reconceptualising our shelter, see New construction below.

We're working with the existing buildings substantially as they are, with alterations focused primarily on making them wind and water-tight, comfortable in all seasons and weathers, and resource-efficient. Where possible we're designing in synergistic functionality which extends usability, adds flexibility, contributes to resource efficiency and confers a greater degree of autonomy in building systems by closing some of the resource use loops involved.

A lot of fancy words to describe a general principle, but what do they mean in practice? We're looking for opportunities to meet as many challenges as possible within a single elegant and cost-effective solution, while avoiding as far as possible boxing ourselves into any corners. That might involve some compromises on our part, but humans are generally much more flexible and adaptable than buildings.

Examples

Situation: - the main building has unmortared dry stone walls. The lack of mortar means the wind gets in. They were soaking wet in wet weather with driven rain working its way through to the interior, and uncomfortably hot in summer with the sun turning the south-facing wall into a giant radiator heating the building through the night. It has 4 small rooms, originally with no interconnections, ie. no internal doorways and no stairs.

Solution: External stone steps already existed either side of the building. So we decided to keep the communication pathways external and simply extended the roof out over the external steps. This one solution solved all the issues - provided covered stairways without losing internal space and created sufficient roof overhang to both shade the walls from summer sun and prevent driven rain from reaching them. It means we can now simply insulate and plaster internally and the building will be warm, dry and wind-proof. The compromise - the need to go outside to move from room to room - really only involves putting on a jumper in cold weather and is a very small price to pay compared to all the work and expense of a more standard approach of pointing and rendering and putting in internal stairs. All we did inside was put a single doorway through between the 2 upstairs rooms.


Situation: - the right half of the main building had no front wall.

Solution: We turned this into an opportunity to create an attached greenhouse for growing frost-tender winter vegetables and exotics while simultaneously processing grey water from the building. Extending the greenhouse over two floors creates a well-lit space suitable for use as a classroom as well as communal living room. The east- and south-facing full height glazing allows what limited low-level winter sun the building gets to heat thermal mass in the walls and floors (passive solar gain), while roof overhangs and seasonal vegetation prevent summer sun from doing the same.

New construction

We're exploring a more distributed, decentralised idea of 'house' here: partly because of space limitations in the existing buildings, partly because of their questionable status within existing planning regulations (*), partly because of the appeal of the concept itself, and mainly because we want to develop the quinta into a demonstration site hosting workshops and courses as well as being our home. This creates a need to balance privacy considerations with utility and the ability to cater for larger numbers of people.

The communal/social functions of a home, together with classroom-type space, will be grouped together in the one building, but the more private spaces like bedrooms, bathrooms, etc, are/will be dotted all over the land in the form of small natural buildings and more temporary/seasonal structures. Essentially the whole farm becomes part of the 'house'.

It's a very flexible arrangement. Rooms can be added and removed or repurposed as required. Everyone has their own personal and peaceful space that's detached and distant from the communal space. Buildings are either temporary, or small enough and natural enough to be below the bar when it comes to codes and permissions and, despite requiring more materials in aggregate, can be constructed sustainably from natural materials mostly sourced onsite in easy bite-size chunks. Larger numbers of people can be accommodated in summer with the addition of seasonal rooms in the shape of tents and tipis.

There's also flexibility to create synergistic relationships between rooms – like a bathroom-greenhouse combination where the bathroom water heater's exhaust heats the greenhouse and the humidity and grey water get processed through the greenhouse's plants. In summer, the greenhouse acts as a solar collector to heat the water for the bathroom.

This does mean there are times when we have to leave a cosy warm living room and step into the teeth of a gale to go for a shower or to bed, but that's actually part of the point – once this way of life becomes 'normal', then the teeth of a gale becomes a perfectly acceptable thing to step out into. Just another natural phenomenon doing its thing in the corridors of the 'house'. It blurs this conceptual separation we have between 'home' and 'out there' until eventually it ceases to exist.

* Existing planning regulations simply don't legislate for the kind of use many eco-immigrants are envisaging for their structures, so strictly speaking they're neither illegal, nor expressly permitted. The rules have to be bent a bit to make them apply and that's open to different interpretations. Clearly at some point the Portuguese legal system will need to catch up with what people are doing but its wheels turn extremely slowly, so in the meantime we exist in a kind of legal limbo land. Hopefully by the time it does a more enlightened approach to sustainable natural building will apply.


Cob bathroom

Cob bathroom


Some random thoughts on principles, techniques and materials ...


Wind and waterporoofing

Rather than compromise breathability and the free passage of water through the structures by applying waterproof coatings and installing damp courses and waterproof barriers, we are designing around the buildings to keep the structures naturally dry.

Back wall showing water ingress

Rainwater run-off, which finds its way in by running down the slopes behind the buildings, soaking through the soil and following the solid rock surfaces which form the back walls of the lower rooms, is being caught and diverted before it reaches the back walls. A combination of open channels cut into the rock itself and cement-lined drains intercept the water and take it away. Paved surfaces between the drains and the back wall of the buildings with a roof over the paved area prevents rain falling directly behind the building. In this way, we hope to keep the sub-surface sections of the rear walls dry, as well as the rock faces themselves.

Work on this was substantially completed in May 2012 for the main building, though with drought conditions before and after, it was a good 6 months before we saw this construction properly tested. So far, it's working well and the back of the building is completely dry apart from the very corner of the north side of the building where we still have some paving and the bottom drain to finish.

We repeated the process in early 2013 for the smaller building.

Timber-framed roof extensions (balconies, porches, stairwells, lean-to roofs, etc) are used, as noted above, to create sufficient overhang to keep driven rain off the dry stone walls.

This then means all we have to be concerned with keeping out is the wind. This will be achieved with a combination of lime mortars, light clay straw insulation and earthen plasters made from clay brought in from a nearby brickworks.

Mortars, renders and plasters

After thoroughly investigating lime-based mortars, renders and plasters, I've ended up leaning mostly towards clay, which is the material traditionally used in this region anyway. Clay has some excellent properties. It's a breathable material which regulates both humidity and temperature, absorbing or releasing water vapour depending on ambient humidity and moderating temperature swings in the same way. Cool walls in summer and warm ones in winter. It's also anti-static and detoxifies the air in a room. It's a mechanical rather than chemical set, so it can easily be moistened and repaired. Any waste can simply be returned to the soil. It's also very pleasant to work with, unlike lime which is too caustic to be used without protection.

We'll use lime mortars and plasters in areas where increased strength and/or water resistance is required, and to point internal schist stone walls which will be left unrendered.


Insulation

We've used cork insulation for the roofs, sandwiched between rough timber boards covering the original chestnut rafters and a membrane, battens and the original roofing material on top of that: slate for the larger building and clay tiles and schist for the smaller. Cork insulation is easily obtained in Portugal, cork production being one of the country's main industries.

For walls, we're using light clay straw underneath clay plaster.







© W Howard 2008-2017 | HTML5 | CSS | Website by W Howard | Hosted on 100% solar-powered webservers through AISO