The MOByök. Laser cut reclaimed cardboard, locally made.

Here is one last article about my current business venture in Barcelona. After having written about the VOC-free drywallstips on energy saving, the PVC-free piping, our reclaimed bathroom sinks, the natural wood fibre wall insulationbathrooms and kitchensbedsour office, and some of our furniture, I would like to mention a few more materials and actions we have taken at yök Casa + Cultura in Spain. Recyclability was always a key factor in choosing the materials, as well as proximity.

MOByök

imageyök’s Instagram/via

The MOByök is a multifunctional piece specially designed for our hotel rooms. You can use it as a stool, table base, foot rest etc. but mainly it is meant to raise your suitcase to a comfortable height while living out of it. Together with designer Marcello Cannarsa we designed it, and fabricated it at the FabCafe inside the MOB co-working spacearound the corner from yök. Marcello collected used cardboard boxes from businesses in the area, laser cut them and then assembled them using only a belt. By avoiding adding other materials such as glue, we made sure the whole thing can still be recycled after its (second) use.

Eco-paint

imageyök’s Instagram/via

It wasn’t easy finding VOC-free paints that were also within our budget and worked well. Sometimes with eco-paint you have to add more layers and it still doesn’t cover the wall perfectly. We managed to get VOC-free white walls thanks to CapaSilan by Caparol, whose VOC content is < 1 g/l. A few walls (like the one in the photo below) had a beautiful textured colour so we managed to preserve them as they were by sealing the pores with a natural latex.

image© Carlos Barruz for yök

Good tourism

image© yök Casa + Cultura’s business plan using the Business Model Generation canvas

Last but not least, especially in a city affected by mass (bad) tourism and high air pollution, at yök we are challenged to come up with a sustainable way to do business without sacrificing the experience of our guests, both visitors and locals. The 3 Ps (People, Planet & Profit) are our guideline. We are by no means perfect, but we hope to set an example and a platform for better tourism in our city. Nothing sums it up better than our Manifesto.

I would like to thank Treehugger and especially Lloyd Alter for the opportunity to document our eco-renovation here over the last 8 months since the first article and photos of the space before renovating in february. I received many encouraging emails, more questions and interesting comments from readers around the world. Please do not hesitate to contact me with any thoughts or to stay with us when you are in Barcelona next time.

natural bed by Astral Nature at yök Casa + Cultura

yök Casa + Cultura is more than just a place to stay the night, but, at the end of the day, whether you are in Barcelona on holidays or for work, you want a good night’s sleep. We looked for the right bed for a while and found it, locally! Natural materials were essential as a great deal of effort was put into using VOC-free materials during the renovation, like the paint, wood fibre insulation and drywalls.

yök Casa + Cultura’s Instagram/via

We had our eye on some of the luxury brands like Coco-mat, from Greece, and Naturalmat, from the UK. We also came across Ecomatalasser, a mattress maker that uses the traditional Catalan technique of the 14th century and locally grown materials like wool, algae, lavender and grain husks to make fully biodegradable mattresses. Since the two first brands were well over our budget, and had to be shipped over, and we weren’t too convinced about the comfort and maintenance of the ones from the Ecomatalasser, we were delighted when we found a local mattress maker that uses also all natural ingredients.

yök Casa + Cultura’s Instagram/via

Astral Nature’s mattress layers are made from viscose fabric, silk, camel wool, cashmere, cotton, natural latex, and coconut fibre. We went for the Nerva model, a pocketed spring mattress. Apart from the various layers of natural materials, it has some springs, protected by fabric to make the bed last longer and not loose its shape over the years. Longevity and comfort, apart from eco materials and local production, are important to us. Astral Nature also has mattresses without springs, like the Arctic model.

All Astral Nature mattresses are manufactured based on carefully selected insulation and temperature control materials of natural origin which, as well as being more comfortable, preserve the body temperature and process moisture effectively.

Of course materials like silk and camel hair are not produced locally, but the mattress factory is located 2 hours by car from Barcelona. This made it convenient for us to redesign the bed base with Astral. We weren’t too keen on the bases, both because of their design and because they weren’t made from eco-friendly materials. Luckily, Astral was willing to make some alterations. We asked them to use an FSC-certified plywood instead of wood vinyl and MDF, which contains a high degree of resin, making it often toxic and/or non recyclable. Instead of covering up the wood with a synthetic upholstery, we asked them to leave the wood visible and simply protect it with a VOC-free varnish by Rubio Monocoat. The beds come with a storage space under the platform that holds the mattress, which we need to hide away duvets and blankets during the summer. The cover of the base that lifts up is 100% linen and the head rests are made from wooden doors that were left over after the renovation.

© Carlos Barruz for yök

So far, our guests have commented very positively about the beds and we hope Astral will add our re-design to their catalogue. Our next goal is to design organic bedsheets, or, even better, find an eco-friendly hotel laundry that provides them to us. There’s a niche in the market here that needs to be filled… just hinting!

yök's green bathrooms save water and use friendly and recycled materials

It seems there is more to tackle than saving water when you want to go green in the bathroom. A while back, I wrote about why reclaimed sinks were the most eco-friendly option for wash basins at yök Casa + Cultura.

image© Carlos Barruz for yök

Regarding mirrors, the most eco-friendly option, since they are not recyclable, is also to choose them second hand. This, as with all reused objects, avoids more of them being made. In general, we tried to use as less material as possible without making the bathrooms uncomfortable. Instead of shelves for example, we placed plenty of hooks on the walls.

image© Carlos Barruz for yök

When it comes to the wet areas, we only covered those with tiles that needed to, like the inside of the shower and the bit above the sink. These square coloured tiles are the classic bathroom tiles used in Barcelona. Made in Spain by Fabresa, dry clay is locally obtained and undergoes a quick double firing process, saving energy and CO2 emissions both in the transportation and in the fabrication process. As with all tiles, it will be difficult to recycle them (only a downcycling is possible), which is why it is important to choose a timeless design, good quality material and as less surface as possible. The rest of the walls are painted with white low-VOC paint, suitable for humid environments.

Most of the floors have a fabulous mosaic flooring from 1900 which we restored. Where areas were missing (one of the rooms used to house the kitchen, which didn’t have a noble floor) we just filled up the small area with cement and sealed it. We managed to avoid shower curtains, usually made from PVC and not long-lasting, by installing recyclable glass doors.

imageyök Casa + Cultura’s Instagram/via

The lights are second hand porcelain arms which we rewired so that they can fit LED bulbs. The vintage switches and plugs are new and very long-lasting as they are made of porcelain. They are also made locally, by Fontini.

After careful studies by Xavier Mor from Renòwatt, we came to the conclusion that the greenest option to heat our hot water for the showers are efficient gas heaters if we offset the CO2 emissions; which we will!

image© Carlos Barruz for yök

Last but not least comes the water in the bathrooms. At yök we do not only work hard to save energy, but also water. According to Airbnb, guests in Europe renting a home use 45% less water than when staying in a hotel. Even though, there is a lot one can do to reduce the water consumption in holiday lettings, especially in a country that is feeling the stress of the water crisis.

Here is a recap: we installed Roca’s L20 series of shower heads and faucets. They are equipped with aerators and Cold Start, meaning the hot water is only triggered if you move the handle to the left. Most taps fire up the hot water every time you lift the handle in the middle position, wasting energy unnecessarily. The toilets have a dual-flush system as it is the easiest for guests from all different cultures to understand without having to leave instructions.

image© Carlos Barruz for yök

Upstairs in our office, we installed the w+w toilet by Roca (top photo). It recycles the water used in the sink to flush the toilet. However, as it is made from a huge amount of un-upcyclable material (porcelain), we are not sure saving some water will make up for that. In fact, Roca had LEED analyse their different toilets and some of them, like the Meridian series we installed in the apartments, save the same or more water depending on how you use it. In the end however, we installed it not only as a water-saving and conservation maker (this is definitely working) but for space-saving reasons. The only way we could fit a toilet and sink in the small space provided was to install the w+w.

Coming up next are our branded soap dispensers to remind our guests that water is precious while they soap themselves with 100% natural citrus soap made in Valencia.

A couple of years ago I came across Catalan designer Curro Claret’s upcycled shop design for Camper, fabricated by former homeless people. So when we needed 16 bedside tables for yök Casa + Cultura, we called Curro Claret, and he got to work, together with the guys from Arrels Fundació. Here is the result!

image© Juan Lemus

Claret’s metal joint allows for many designs according to the reclaimed material they found in the street. In the workshop, Aurelio, José Luis and Valerio then combined, cut, polished and assembled recovered pieces of furniture to turn those scrap materials into beautiful bedside tables and stools.

image© Juan Lemus

Since 1987, Arrels Fundació has been helping homeless people in the city of Barcelona. Up until now, they have accompanied over 8.000 homeless people in their path towards work, autonomy, offering them housing, meals, social attention and health care.

image© Juan Lemus

What does Arrels do to help people feel useful?

Pieces of wood with a second life
With a simple piece of metal, wood picked up from the street and a desire to create and transform, since 2010 a group of homeless people construct stools, lamps and other pieces of furniture. The project has won awards; however, until now, the most important recognition has been a collaboration with the company Camper to decorate one of its shops with the furniture.

image© Juan Lemus

image© Juan Lemus

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© yök Casa + Cultura

When you design an apartment for holiday letting, everything has to be easy and self-explanatory. At yök, we want our guests to be able to reduce the ecological footprint of their stay without sacrificing the experience. Investing a bit into home automation was therefore necessary.

A key card system in an apartment for a minimum of 4 people is no use- you can’t force people to take out one of the cards when they leave. Instead we believe that if we make it straightforward enough, people will participate. We installed a lovely ON/OFF switch by Fontini in the entrance of each apartment. When you go out, you turn it off, knowing that everything electrical switches off except the fridge and a plug in the kitchen in case you need to leave something charging. It’s easy and you don’t have to look after a key card, as the entrance door opens with a code.

imageyök Casa + Cultura’s Instagram/via

We also installed sensors in all of the windows and balcony doors, so that the AC/heating system switches off automatically when you open a window. Since the apartments are quite large (2-4 bedrooms), and the system is centralised for each one, this is important in a place with a climate like Barcelona (quite cold in the winter and really hot in the summer).

We were debating for a while whether to install AC at all, but in the end we had to give in, in order to provide comfort for people used to different climates. After analysing various systems and brands with local energy expert Xavier Mor from Renòwatt, we decided to go for Mitsubishi’s Ductless Air-Conditioning and Heating Units. It is ENERGY STAR® certified for its energy use both for cooling and heating. With one system doing both, we did not have to install a secondary system to heat the place in winter. However, we believe that our guests will hardly use the AC/heating if they follow our guidelines of traditional ways to deal with the local climate.

imageyök Casa + Cultura’s Instagram/via

When it is hot, first open the windows and get a breeze in there! Cross ventilation does wonders. If there is no breeze (like now in August!), use the ceiling fans in the communal areas. If you are out during the day, close the traditional sunblinds so the rooms stay nice and cool for when you get back later in the day.

Insulation is also key, both in the summer and winter as well as for acoustic reasons. We insulated all our walls with natural wood fibres, and managed to insulate the traditional wooden sliding balcony doors. Double glazing was relatively easy to install, but getting rid of the thermal bridge in the gap where the doors slide in was trickier. In the end, our very talented carpenter, Maño, managed to insulate the doors by fitting them with rubber bands and brushes.

imagePetz Scholtus/via

After having sorted out the climate, we looked at everything else that consumed energy and managed to only get A+ certified appliances in. Together with the local lighting experts Anoche, we fitted out the whole place with LED lighting. In places like corridors the lights switch on and off thanks to motion detectors. By doing most of the lighting ourselves and using a lot of indirect LED strips, we saved a lot of material. Revamping old lamps from the second hand market was also fun. The wooden ceiling fans and recyclable aluminium reading lights are traditional designs, locally produced by Faro Barcelona.

imagePetz Scholtus/via

To date, we don’t have solar power yet for two reasons. First, we don’t own the building and therefore the rooftop, where the panels would have to be installed, is not ours. While this might be able to be negotiated with the owners, the current spanish law on taxing solar power is not negotiable. Sadly, our current government, with the excuse of the crisis, wants to drastically cut its subsidies and even retroactively cut subsidies for existing solar projects, resulting in homeowners and companies facing insolvency. Spain would then possibly be the only country with a tax solely on those who generate their own electricity. So until the Spanish government comes to their senses and gets rid of the proposed “sun tax”, we are not prepared to invest into solar power.

imageSom Energia/via

But what we can do now, is join Som Energia, a renewable energy cooperative. By becoming a member, Som Energia provides us with electricity and certifies that the amount of sold energy has been generated by wind turbines, solar panels and biogas plants and invests directly in renewable projects to develop a sustainable economy.

We also believe in saving energy by making the consumption visible. The company Habitat Projects, who also set up our home automation system, installed electricity and water monitors for each apartment. We will use this information to get guests to compete for the most responsible amongst them, and will reward those that manage to use less during their stay.

If you have any more ideas regarding reducing the energy consumption of short term lettings, please share them!

We use non-toxic materials & products! Green cleaning, voc-free paint, PVC free, …

Enjoy some lush original 1900 carpentry! Fully restored and insulating to save energy and block street noise.

Get ideas from yök for saving resources at home! Less water, energy and stuff = more savings. 

yök Casa + Cultura office before and after

The eco-renovation of yök Casa + Cultura is still in full swing but this week we moved into our office. This small (35m2) yet multi-functional space, equipped with a kitchen and toilet, serves as our reception as well as event space. The best thing about it: our terrace, overlooking Barcelona.

imageyök Casa + Cultura’s Instagram/via

Up here on the 8th floor, an extension from the 70ies to the original building from 1900, there wasn’t much to salvage. However, we decided to restore the traditional terrazzo we discovered under a glued layer of cork in order to save extra material like for example a cement or wooden floor.

imageyök’s Instagram/via

In order to make the space cosier, we added wood to the interior. Our carpenter David used some salvaged timber sleepers he obtained from the Catalonia Railway Museum in Vilanova, a nearby town, and turned them into a beautiful interior.

imageyök Casa + Cultura’s Instagram/via

The kitchen countertop, ECO by Cosentino, is also made in Spain, from upcycled material such as mirror, glass, porcelain, earthenware and vitrified ash. The company claims that 94% of the water used in its manufacturing process is re-used. We also like that it is highly durable and easy to maintain.

imageyök Casa + Cultura’s Instagram/via

All our appliances are energy-efficient and A+ or A++ certified. The AC, which we hope to use only in the very hot or very cold weeks, is also A+ certified, both for heating and cooling. In order to minimise the use of the AC/heater, we made sure we can cross ventilate the space. Insulation is also key. The ceiling is insulated with a layer of Isonat wood fibres and Knauf’s A+ certified low-VOC drywall. We installed new wooden doors with double glasing and are in the process of installing a plant pergola on the terrace to create shade on the outside facade. If our budget allows it, we will install a vertical garden to further insulate the space from the outside.

imageyök Casa + Cultura’s Instagram/via

We also took care of basic things like VOC-free paint and a DIY lighting installation made from a minimum use of material and LED light bulbs. Our light switches and plugs (large image above), collection 5.1 designed by Oriol Guimerá for Font Barcelona, are made locally from brushed stainless steel which makes them very long lasting and recyclable.

We use second hand objects and locally made furniture from certified wood, and are looking forward to receiving the clamp-a-legs by DE VORM, to make flexible tables with salvaged table tops.

Although we had our doubts about Roca’s w+w toilet (a toilet with an integrated sink and gray water recycling system) due to the large amount of material it uses and its high price, we realised that it was the only way we could have the bathroom in the small space suitable for it. Of course we like the fact that it recycles the gray water.

imageyök Casa + Cultura’s Instagram/via

Barcelona’s tap water isn’t very nice to drink unfiltered, so to avoid bottled water we installed reverse osmosis. The wastewater is being collected in a tank on the roof so that we can use it to water the plants and for cleaning. The kitchen tap, L20 by Roca, has an integrated aerator and cold-start.

On our to do list are bee-friendly plants on the terrace to help cool down the place while providing food for urban bees, and, a washing line to dry our clothes energy-free. All of this will be ready when yök Casa + Cultura opens the apartments from july 28th!

An update from the #ecorenovation via our Instagram feed. Oto has started with the zero-VOC paint, José has stripped all the old paint of the original carpentry, Hector and the team from Anoche are busy with the lighting, David is finishing the wood work in our #aticoyök and Marcello and Petz have assembled the #MOByök after lasercutting the pieces at the FabCafe Barcelona.

Román and Isonat Flex insulation material made from wood fibres

Rockwool, or mineral wool, is still commonly used here in Spain for insulation due to its low cost. I read up on it, and as Lloyd, “am still confused” whether this classifies as a green building material or not. Since it is made from a non-renewable material (volcano stone), requires a high amount of energy during production, and is not recyclable or reusable (since we have to cut it to size and there is no take-back program set up), we concluded that we could find a better material.

image© Marcello Cannarsa

We looked into cellulose made from recycled paper that is sprayed in between the drywalls, but had to discard this idea due to the high cost, and because the cellulose is difficult to get out for recycling in the future. Since you need to hire special machines for the installation, this only makes sense economically if you have quite a lot of walls to insulate or are constructing a new building.

image© Marcello Cannarsa

We kept looking for eco-friendly alternatives and found Isonat Flex by the company Buitex, made in France from wood fibres of pruning and cleaning local forests. This semi-rigid material is still roughly three times the price of mineral wool, but at least as easy to install and much less harmful for the person handling it. It fulfills all the criteria for both fire-resistant, thermal and acoustic requirements and to us it turned out to be the greenest alternative available. Here is why:

Durability

According to Buitex, these plant-based insulation products last the same and even longer than the more traditional ones. Their research lead them to select the best performing ingredients to avoid clumping and degrading, and they estimate it performing during 30 to 50 years.

image© Marcello Cannarsa

Recyclability

In order to obtain high durability, Isonat Flex is made of more or less 85% wood fibres and roughly 15% recycled polyester. We weren’t too happy about this fact at the beginning as adding a non-biodegradable material (polyester) results in the wood fibres not being compostable any more. (Even though the distribution company here in Spain claims it to be a compostable material…)

However, we understand that mixing in a technological material is probably necessary to achieve quality and longevity, and what convinced us is the fact that Buitex takes back used insulation materials to recycle properly (upcycle) at their factory in France. The same is done with surplus material during production and left-overs from building sites.

Easy installation

Our builders confirmed that it was not more difficult to apply Isonat Flex to our A+ low-VOC drywalls than mineral wool. All you need is a mechanical saw to cut the material to size. Having said that, correct installation is key for this, or any semi-rigid insulation material, to work.

image© Petz Scholtus

Natural comfort

We are glad to obtain insulation quality by means of a renewable material such as wood. The idea is to help regulate the temperature in both summer and winter and obtain a maximum comfort all year round.

In order to reduce heating and cooling costs, apart from insulating the walls, we will also install double glazing in the traditional wooden windows and balcony doors, and install a green facade to insulate our top-floor office space.

Here a few more photos from our Instagram feed. From top to bottom we have Fem Ferro building a long-lasting, fully recyclable cabinet for our terrace, Tudor figuring out how to install the w+w, Vitali the electrician, and Maño the carpenter.

I would like to share with you our reasoning behind choosing the sinks for our bathrooms at yök Casa + Cultura. The ninth point of our manifesto explains our criteria quite well:

9. Apply good design (useful, beautiful, fun, detailed, eco-friendly, functional, affordable, long-lasting, honest, local) to everything: interiors, business model, service, activities, and shop.

Good design is what we strive for and we are also on a limited budget. So what we thought was the most eco-friendly solution at first, was to go for as less material as possible. After all, the most eco-friendly material is the one we don’t use! For that reason, a few years ago when designing the R3project, I came across the Kalahari sink, designed by Ramon Benedito for Roca:

A sink made from one single piece of ceramic. The fact that it is a shelf and a sink in one piece minimises the material used drastically. Whether the aesthetic end of life is prolonged as well is arguable but it definitely creates less waste than a standard sink.


© Roca

Porcelain has the big advantage of being long-lasting, at least on a technical level. But how many sinks get thrown out due to an emotional reason; because it is out of fashion or we grow tired of it. To foresee the emotional longevity of things is often harder than making stuff last physically. Even though we found some nice locally-produced designs, the fact that porcelain is difficult to recycle (we would be talking about downcycling), kept us looking for other solutions.

When it comes to materials suitable for sinks, plastic is very funky and especially recyclable. We found the LTB sink by WET, made in Italy. These sinks have the advantages that they are very lightweight (2kg!) and made from 100% recyclable LDPE. They are easy to clean, child-friendly due to the round shapes and pretty much unbreakable. I am not so keen on the optional LED lighting but I don’t think it does any harm either.


© WET

Still, while discussing this with my colleague Jenna Watson, among other things, she reminded us that we should think about the entire life cycle of the sink, and consider its longevity. Does it make more sense to opt for porcelain ones that last more than a lifetime of the bathroom? Waving back and forth between whether to prioritise recyclability or durability, we thought we’d look into finding reused porcelain washbasins. And alas, at Otranto here in Barcelona, we found 5 beautiful sinks that were salvaged from an old B&B. Of course we were lucky to find enough reused sinks that fit in our spaces.


yök Casa + Cultura’s Instagram/via

Buying second hand can be exhausting but to me it is also fun. Once you find the object, you usually also have to invest some time to fix it up. In this case, we need to find fitting low-flow faucets, cover up the remaining holes (back in the days there were two taps, one for cold and one for hot water) and find a fitting drainage system. We believe that all of this is well worth it because we saved some unique sinks from the dump and prevented new resources from being used. Moreover, our washbasins tell a story, thank you for reading it!

After putting up low-VOC drywalls, we are on to the water installation for yök Casa + Cultura’s eco-renovation. One of our goals is to keep the apartments 100% PVC-free. We also aim to use materials in such a way that they can be recycled in the future. And we don’t believe that all plastics are bad. When it comes to the water pipes, we think that a non-toxic plastic plumbing system is the better solution to the traditional copper one.

image
© Petz Scholtus

For our pipes, we use PEX, or crosslinked polyethylene, by Uponor. The tubes are flexible, easy and quick to install, and long-lasting. Uponor explain on their blog that “the process by which copper is mined, refined, transformed into end products, and then used—such as pipe—is very energy intensive, using a great deal of non-renewable energy during its lifetime. In fact, if a Life Cycle Assessment (LCA) is undertaken for both PEX and copper, PEX fare much better. Simply put: during its lifetime, a PEX-based system has a lower overall energy content than a similar system made from copper.”

Copper is indeed more expensive, and even though it is also recyclable, requires a lot of energy to do so. Our workers say that installing PEX is much more comfortable than copper.

image
© Marcello Cannarsa

Benefits of Uponor PEX over Copper and CPVC according to Uponor:

- Flexible for fewer fittings, reduced leak-point liability
- Resists corrosion, pitting and scaling
- Retains more heat in hot-water lines
- Resists condensation on cold-water lines
- Expands up to 3X its diameter to help resist freeze damage
- Connections do not require the use of dangerous chemicals or solvents
- Offers a complete lead-free system from inlet to faucet
- NSF International certification for water purity
- Backed by a 25-year limited warranty on PEX tubing and ProPEX fittings

Last but not least, the PEX we buy in Spain is made in Spain, just like our drywalls.

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Drywalls have in the past often been criticised for being “cheap”, nondurable or flimsy, and bad for your health. So we tried to find another solution to divide up the different apartments and rooms for yök Casa + Cultura. Most of the ideas we came up with however, were too experimental, meaning costing too much money or/and time. So we went back to studying drywalls available in Spain and found Knauf.

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© Marcello Cannarsa

Knauf’s panels for room partitions and suspended ceilings have been rated A+ regarding VOC emissions in interior spaces. The panels are made of 100% recycled cardboard and natural plaster, of which a part comes from pre-consumer recycling.

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© Petz Scholtus

Moreover, this technique allows us to put the new walls on top of the mosaic floor without damaging it. In the future, walls can simply be removed without damaging the original Catalan Modernisme features. No wet material like cement, sand or glue is needed. Another advantage for us is that the material is made in Spain, which reduces the transportation impact, and has obtained the UNE-EN ISO 14006 Eco-design certificate by Aenor.

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yök Casa + Cultura’s Instagram/via

The panels are set up using standard metal guides that can easily be recycled in the future. The panels itself can also be fully recycled, separating the plaster from the cardboard. This however, is hardly being done in Spain at the moment because it is currently cheaper to dispose of the panels as landfill, than to bring them back to the factory. Let’s hope that by the time our walls need to be recycled, the company has a take-back program for its material in place!

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© Marcello Cannarsa

Instead of mineral wool, we opted for natural sheep wool for insulation. In the end, using drywalls and sheep wool results in much less volume of material than most other materials, and hence in less transportation and packaging. The walls fit all our criteria regarding health (VOC-free), safety (fire-proof), environment (local production and non-toxic), comfort (sound-proof) and cost (easy installation).