Since completing the external stairways at the end of September, the southwest corner of the roof has been sitting waiting for suitable schist slabs to complete its covering. The last load of stone (from the community stone mine about 1.5km away further up the mountain, dug out and brought down by man-of-many-machines Senhor Angelo from the village directly above) contained some huge slabs of good-quality roofing stone that were ideal.

The schist is enormously variable. Even across the space of a few metres, it can vary dramatically in colour and density. The stone of the small building the other side of the quinta is quite different to the larger building, even though the mines for each – directly behind and above each building – are less than 150m apart. So it’s easy to tell the new stone from the original roof stone by its colour. In time though, lichens and mosses will grow on it and even it out somewhat.

The curve of the building and its eccentric proportions – accommodated to the shape and curve of the slope it’s built on rather than vice versa – is clear from these images and illustrates nicely why random schist slabs work so well as a roof covering for these dry-stone schist buildings. Imagine trying to cover this roof with uniformly-sized roof tiles!

In this last image, you can also see the foundations for the toilet that have been put in behind the building. The walls for this will be constructed in cob and there’ll be a turf roof extending from the back of the building to the slope behind it. This is a crucial part of keeping the building dry: at the moment, rainwater runoff soaks through the thin soil and comes straight down the rock face and into the back of the building. A substantial gully cut into the rock itself and lined with a stiff mix of concrete to prevent water soaking down through and along the bedding planes (which run mainly vertically and perpendicular to the line of the back wall) should be enough to divert runoff away from the back of the house and, with the roof, keep the building dry without resorting to the use of artificial synthetic waterproof barriers.

Yes, it’s using Portland cement, but as I’ve written elsewhere, there are times when its strength and impermeability make it an ideal material for the job. Yes it would have been possible to construct without it if we were enormously skillful, but when the skills required are in short supply and beyond budget, both financially and temporally, compromises become unavoidable. This is a compromise I’ve been prepared to make; mostly, though not exclusively, in structurally critical instances. The cement we use is dug and fired 40km away (around 60km by road) using energy more than 50% of which is generated from renewable sources. As the main contributor of embodied energy to the project, it could be a lot worse.

Many times I’ve gone over what we’ve done, especially following discussions with those of a more rigorously natural perspective, thinking could I have done it differently, and come to the conclusion that for this project in this context, it’s appropriate. A new natural build on a level site has different challenges to renovating an existing natural building perched on a narrow terrace half way up a mountain. Damp and water ingress is a feature of much of the Portuguese rural housing stock and something people appear to simply live with, traditionally providing ways for water to pass through buildings rather than trying to keep it out (though latterly trying to keep it out with large amounts of cement render which has produced a whole raft of problems). Here we are changing the use of the building and having water running through the ground floor rooms is not really compatible with the use we want to put them to.

There goes another principle … but I can live with it.

In doing so the building revealed more of its life story: something we hadn’t been aware of until letting all this extra light in.

See the line running diagonally up the back wall from right to centre? It marks a line of different quality stone (and stone building if it comes to that). There’s another one running down again from the hole at the midpoint of the wall as well, though it’s not so easy to see with the light coming through the doorway.

It seems this half of the building started life as a 1½-storey building with an east-west axis double-pitched roof, the gable end facing the village. It was then converted into a 2-storey building with a north-south axis single-pitched roof before an extra back and side wall to the right of it were added with the schist slab roof extended over both structures. All in dry-stacked stone at that. (And dry-stone work with no clay infill either. While I can’t help but admire the skill in its construction, it’s going to be a long time and a lot of barrow-loads of clay before the building is windtight …)

This half of the building is cut more deeply into the bedrock, which reaches most of the way up the back wall of the downstairs room and also forms the floor. This room has no windows. It used to house the animals that were kept on the quinta. We are going to make use of this immense thermal mass and use it as a store room for all the produce of the quinta. We’ll be creating an earthen floor to even the surface and for humidity regulation. The underside of the upper floor will also be cork-insulated.

Again. we’re able to re-use many of the chestnut timbers that held up the old floor, though there was more water coming in from the roof into the building on this side so roughly 50% of them will have to be replaced.

Looking at the full height of the building with the floors removed, the skill in creating a structure this size purely from stones laid one on top of another with nothing to hold them together never ceases to impress me.

Extending the roof area right round the house in this way will, aside from providing covered walkways, give all round protection to the walls from most direct weather action: a major consideration with dry-stone walls, especially ones that are going to be clay-pointed.

The stairs to the right of the building were already enclosed by the log store, so all that remained was to construct the wooden supporting framework, bridging the gap between the log store and the building. Again, we’ve used round-pole sweet chestnut for the framework and maritime pine planking.

I’m not overly impressed with the ‘ecological’ wood preservative we’ve been using so far. I’ve still not been able to discover the active ingredients, and although it produces a nice-looking finish when dry, the PVA it contains makes it unsuitable for external use as it becomes milky and opaque if rained on. It also appears largely ineffective against wood-boring wasps since we’ve noticed fresh activity in treated timbers. Consequently, I’ll be preserving these external timbers with 2 applications of borax, then linseed oil, and using a more concentrated borax gel or paste to deal with the active infestation in the treated timbers. When your roof weighs 8-9 tonnes, it doesn’t do to have the supporting timbers eaten away …

The left hand stair well is now in the process of being created. The stairs have been repaired and a schist wall constructed (with cement, since it has to support the weight of the chestnut framework).

We didn’t have enough large lengths of chestnut for this stair-well, and our local source of recycled timber has none of the required length, so rather than looking to buy some, we found a long straight chestnut tree in a crowded area of the quinta and felled it for the purpose, leaving enough of a stump for the tree to regenerate. It feels perfect that the renovations should include timber from the quinta, as well as stone and clay.

It has been quite a transformation.

Before … The area in front of the main building in November 2008 before we bought the quinta (above), and below, the building as it was in January 2009 during the purchase process.

During … (above) Where we’d got to by the end of last year. The schist stone roof has been replaced and the beginnings of the log store are complete.

After … (below) Where we’d got to by Friday. The log store, as intended, has all but ‘disappeared’ into the hill. Balcony and patio area now complete

The schist patio creates a large outside eating area and connects the log store and battery house to the main building.

I wonder where that electricity pole went …

Yes, Portland cement-based mortar has been used. It’s a material I feel as ambivalent about as a lot of the green and eco-building movement seems to. Is it ‘natural’ and ‘eco-friendly’ or isn’t it? The stuff’s credentials are as grey an area as its colour. In composition, it’s not a whole lot different to lime mortar, which gets a general thumbs-up from the green community. It requires a higher temperature – and hence more energy – to manufacture, and emits more CO₂ in the process, but it also absorbs CO₂ when it sets, a fact not always taken into consideration. It’s non-porous while lime is porous, so it doesn’t breathe, but whether that’s ‘good’ or ‘bad’ depends on the context in which you’re using it. It doesn’t bio-degrade very quickly, but then neither does rock, and its breakdown products are no less environmentally benign … It has both advantages and disadvantages which, depending on your priorities in any particular context, can tip the balance either way.

In the end, it tipped in favour for the patio floor area and the log store. The steep terrain, the effects of rainfall and the weight of rock and soil the walls of the log store will be holding back once we finish backfilling required a material with a lot of strength. Building a terrace wall out of just schist and soil in the manner of those which shape this landscape is a rare skill now, and even then walls can and do collapse with some regularity after a lot of rain. Alternatives – eg. gabions – would require a lot of rock to be brought in from elsewhere and although it’s mined close by, would still be using a lot of fossil fuel to extract and transport. Not to mention the cost comparison. So cement it was …

Practicalities – which can be as dry as (cement?) dust – aside, it’s been exciting seeing this work come together so quickly. The feeling of space I was already sensing as the first timbers of the trellis went up is now more … ummm … concrete.

No floor!

(This image also shows the rain that’s been getting into the walls. The walls are still uncovered, even though the roof is substantially complete, as we’ve been waiting on the delivery of more schist to finish the back, and still have the roof extensions over the stairs at each end of the building to construct before we can finish the sides.)

Wayne and Chris take down a heavy chestnut beam

Michael removing the final beam

Wayne’s best cheesy grin. Be afraid. Be very afraid …

Em and Chris in the new stair well

Em and the old woman, who’s still trying to figure out the final design of the building

The log store also gained a roof this week. We’re waiting on a new delivery of sand and cement to finish this off, pouring two more concrete columns in the back wall and screeding the roof in preparation for its soil covering. We can then start backfilling behind it, facing the walls in schist and continuing the wall nearest the building up the side of the external staircase on that end of the house. This will provide the base for supporting timbers to extend the roof over the stair.

When it’s finished, the log store will effectively disappear underground as we’ll bring the driveway down over the top of it with the main entrance to the building at first floor level. The exposed schist stonework will look like just another terrace wall. Well that’s the idea, at least.

Log store with roof

While I fetched and carried buckets of water, Ema took charge of the cement mixer.

Chris barrowed the cement down the slope and Wayne laid the slab.

We were done by 11:30am. Not bad for a hairdresser, a car mechanic, an engineer and an old woman.

(The old woman then went on to lay the floor in the yurt porch, but didn’t get finished until after dark so photos will have to wait until tomorrow.)

And yes, we’re still waiting on the delivery of stone to finish the roof, and STILL waiting on the previous owner removing his stuff from the downstairs room of the smaller of the two buildings on the quinta …

The Portuguese are lovely people, but they do seem to have this habit of telling you what they think you want to hear rather than an accurate reflection of the situation under discussion. Yes, it was very nice to hear that my sand and cement were going to arrive on Monday when I ordered them on Friday, but if there wasn’t a hope in hell of them turning up on that day I’d far rather have been told so at the time. Waiting isn’t so much of a problem. It goes with the territory. It’s disappointed expectations that provoke the frustration. Hrrummmph …

It’s been an interesting experience dealing with continual delays we’ve experienced this summer with the building. While on the one hand it’s been very frustrating, especially while neighbours’ and friends’ dwellings undergo transformations from ruins to habitable homes in the space of about 6 weeks under the hands of the local builders, it’s also made space for the buildings to evolve organically at their own pace in their own special way. Having the time to sit and ponder various options for layout, practicalities, materials and aesthetics has resulted in a much more useful, beautiful and efficient end result, and one which continues to evolve as we build.

Anyway, with the sand and cement we had left onsite, we were at least able to build the retaining walls for the slab for the second level of the main log store.

Cork insulation and breathable membrane go on

The view from the inside

With the membrane fixed in place, the roof was ready to start re-laying the original schist slabs.

Laying the schist. Chris looking over the first few courses

Handing up the large schist slabs

Wayne drilling slabs for nailing in place

We are fixing the bottom, middle and top courses of schist slabs in place to prevent any slippage. We’re also creating slightly more overlap between courses than was used in the original roof, both for better coverage and waterproofing and to hold the stone in place. This roof should never move!

Lunchtime today: two thirds of the way up the first half

The end of today: almost half complete

How it used to look before we started renovations

We have no particular objection to sharing the building with the local wildlife, but aren’t so keen on the winter winds and losing all our heat.

With the roof now planked and the wall heads being built up and capped ready for laying the insulation, we’re starting work on pointing the stonework in the interior of the building. It’s a messy job, so one preferably done before we get around to replacing the floors.

It’s been our aim to source our building materials as locally as we can, to use as many natural materials as practicable, and to avoid, where possible, the use of materials (like concrete) that don’t allow the building to breathe. Since local clay-rich subsoil was the original material used as mortar and pointing in schist buildings, we’re using it to renovate this one.

As luck would have it, while skidding about in vehicles during the winter rains, we discovered that we don’t even have to leave the quinta to find our clay. The cut off the track where we park the van is a source of clay-rich subsoil. Not only that, but what’s there needs dug out and cleared anyway so we can park vehicles at slightly less crazy angles. Two jobs completed in the one.

Digging out the parking area

Yesterday I cleared away topsoil and vegetation, started digging down into the piles of broken schist and subsoil that have slipped down the face of the cut, and used a course riddle to remove larger stones. It’s been dry and hot now for around a couple of months, so it wasn’t hard to do. 4 barrow-loads were tractored around to the building, and heaped up ready for a finer riddle and mixing today.

Initially, we’re using the mix as is without the addition of sand as the clay proportion felt about right. A test ball left in the sun to dry formed a solid hard set without any cracks and took a fair hit to disintegrate. We’ll see how much shrinkage we get with the first application and adjust accordingly.

Riddle your subsoil

Add water

Mix to …

… a good gloop

Be sure to have fun …

… while getting to work

Before

After

The clay subsoil is a delight to work with, especially compared to cement. It’s non-toxic, you can happily use your bare hands, any mess can be gathered up and reused, dirt and all, again and again (the set is mechanical, not chemical), and to top it all you can enjoy a mud-pack cleanse and exfoliation while you’re at it. Health spas eat your hearts out!