The Casa de Cos—19th Century Catalan Row Housing

An example of a Casa de Cos, Vilassar de Mar

We had been living in Vilassar de Dalt for some time before we decided to buy a house in town. In the last four decades Vilassar´s population has increased dramatically as it is within easy commuting distance of Barcelona. Although it has been afflicted by urban sprawl, the town retains a well defined centre with narrow winding streets and close packed houses. We had decided early on that if we were to buy it would have to be in that old quarter which still retains its village character. Over a period of months my wife had been browsing the advertisements in the estate agents´ windows looking for something we could afford. Eventually she spotted a house that had the right combination of necessary restoration and price. We visited the house several times, and honestly it was a mess, but eventually we talked ourselves into its possibilities. After closer examination we concluded that the asking price was too high for the amount of work it was going to need. And so, when our offer was rejected we decided to wait and see what would happen. Our timing was right as the Spanish housing bubble had collapsed and forced down prices. Accordingly, a few weeks later the asking price was reduced and we made another offer. We and the sellers agreed on the terms and we found ourselves owners of a property in Spain.

The house is on one of Vilassar´s oldest streets but unusually the part of the street in front is at least three times wider than is normal in the old town. There is a good reason for that but it was some time before we found out why. Our neighbour to the north is the marquis de Santa Maria de Barberà i de la Manresana who lives in Vilassar’s most imposing private residence, a thousand-year old castle. Depending on who we talked to, our more modest home is between a hundred and two hundred years old. Like most of the houses in the old part of the town the front façade is built directly to the property line on the street. There is a small courtyard (eixeda in Catalan) between the back of the house and the retaining wall that separates us from the castle grounds. Soon after buying the house we learned that it is a typical example of what in Catalonia is called a Casa de Cos—sometimes also known as a Casa d’un Cos. Groups of near identical Casas de Cos were built in rows along urban streets throughout Catalonia. They are particularly prevalent in the Maresme comarca, or county, north-east of Barcelona. The Casa de Cos first appeared in the 18th century, was built in considerable numbers throughout the 19th century and new examples continued to be built during the first three decades of the 20th century. During all that time the basic layout hardly varied. The prevalence of the Casa de Cos is tied to the industrialization of Catalonia, specifically the growth of the textile industry. I find it intriguing that the Casa de Cos is so common and that it was built with so little variation in many places throughout Catalonia. Of course, row houses—lines of identical units built shoulder to shoulder—are not unique to Catalonia but it is perhaps interesting to examine this type of structure using our Vilassar house as a basis.

A Casa de Cos in Premia de Mar, dated 1823

The typical Casa de Cos was built to a very specific layout; the stairs so placed so as to divide the ground floor into two more or less equal areas in the front of the house and the back. A hallway runs from the front entrance clear back to the door opening out to the rear courtyard. The layout of the second floor is similar to that of the ground floor. The front facade was also strictly defined so that on the ground floor the entrance was set to one side and a window centred on the remaining space. There was a single window on the second floor centred on the entrance doors below. There could of course be variations in the details. Sometimes the ground floor window was eliminated leaving only the doors as an opening. The second floor opening would possibly be extended down to create instead a small balcony. There were also variations in decor and finishes. For example, some Casas de Cos had finely finished stone work for the lintels and jambs of the windows and doors, but most had painted stucco covering plain brick work. These were houses that were meant to be economical to build. We changed the street façade of our house during the renovation by adding a second window directly over the ground floor window and raising a parapet wall to enclose a new rooftop terrace.

Row houses developed in Europe during the industrial revolution as a means of providing medium density housing for industrial workers and their families. For Anglophones the term row houses is sometimes replaced with “terrace houses” and brings to mind images of working class neighbourhoods in England—think of the television show Coronation Street. With the movement of people from the countryside to urban areas, property owners maximized their profits by building standardised units and squeezing as many of them as possible on a given area of land. Because of the delayed state of industrial development in Spain the row house developed later in this country. In Vilassar de Dalt the appearance of the Casa de Cos coincides with the establishment of textile factories that in the 19th century became the backbone of the town´s economy. Rows of houses clustered around the factories to house workers and managers. Often the factory and housing were built at the same time as one single project financed by the factory owner who wanted both to attract workers and house them nearby. In neighbouring towns, such as Vilassar de Mar and Premia de Mar, the Casa de Cos also served as housing for fishermen and their families. It should be noted that these towns also had significant textile industries. On the other hand the Casa de Cos is absent from Alella, Arenys de Munt, Calella, Malgrat, Mongat or Premia de Dalt, all nearby towns but which did not have textile industries.

A row of Casas de Cos in Vilassar de Dalt. Most of the houses have been renovated, some of them beyond recognition.

Our older neighbours have told us that our house is one of at least four on the street that were built to an identical plan. This is not now apparent as over time the other houses have been altered almost beyond recognition with the addition of extra floors or changed façades but the houses as originally built would have been all much the same. Of the houses on our street, ours had been the least altered. The simple plan of the Casa de Cos allows it to be renovated with relative ease to modern standards of comfort. Across the street, neatly illustrating the symbiotic relationship between Casas de Cos and industry, is an old factory now converted into several individual houses. It is not obvious at first but Vilassar de Dalt retains one of Catalonia´s most extensive conglomerations of early industrial workers´ housing and industrial buildings. The last of Vilassar´s textile factories closed in the 1980s but several empty structures remain awaiting conversion to new uses. One is presently in the process of being changed into the town library.

The phrase Casa de Cos in Catalan means literally house of a body, the “body” in this case being a unit of length. However, in this instance the word cos derives from Latin cursum which meant this portion of land. It was an ancient unit of measurement used to divide land and later used in the construction of the traditional Catalan masias, or fortified farm houses. As unit of measurement the cos was based on the maximum span of a beam made from the native white pine (Pinus halepensis) trees. A Casa de Cos was usually built one “body” wide, but it could be a “body and half” wide or even more. The owner of a property would have asked the municipality for permission to divide a section of land into coses. A cos is approximately 20 pams wide. (A pam is literally a hand span with the pam de Barcelona set at 19.43 cm and the pam de destre at 23.5 cm.) Our house in Vilassar de Dalt is roughly rectangular in plan fitting between two parallel party walls, the corners not quite forming 90 degrees. The long axis of the house, from the inside faces of the front and rear walls, is 10.4 metres, the inside width of the house is 4.70 metres. These are typical measurements for a Casa de Cos. Presumably, our house was built using the pam de destre as 20 pams de destre equals 4.70 metres. Throughout Catalonia the Casa de Cos could vary between 20 and 30 pams with some exceptional examples up to 40 pams.

Invariably, the typical Casa de Cos consisted of a ground and second floor. Only in renovated houses would there now be a third floor. Entry into the Casa de Cos is via a pair of massive wooden doors. Although they now serve as decorative features originally the massive doors would have had a functional purpose as they led into the largest room of the house, a space that would have served the original owners as a workshop or storage area. The oversized doors would allow large objects to be moved in and out of the house. The front rooms have now, of course, been converted into living rooms. In our house we have created a threshold by adding a pair of French doors just inside of the main doors. Located near the centre of the house are the stairs to the second floor. The stairs were positioned so as to create a direct uncluttered passage from the front entrance to the eixida, or courtyard, behind the house.

Ground floor plan of a typical Casa de Cos. The front of the house is at the right.
The eixada, or rear courtyard is at the left.

A rebost, or pantry was built under part of the stairs. Beyond the stairs is the kitchen. By moving the door of the pantry from the kitchen to the hallway we added a downstairs bathroom with access from the hallway. The most notable features of the kitchen are the fireplace and bread oven. The bread oven consists of two parts; a lower chamber for the fire and the upper chamber where the bread was baked. The two chambers are separated by a masonry grid. The roof of the oven is a dome of roughly 1.4 metres in diameter. The bread oven was built in the space under the stair landing. The present fireplace has a chimney leading directly to the roof but the bread oven never had a separate chimney. Originally the fireplace and oven would have been vented by a large hood that drew the smoke up a single chimney. Smoke staining of the stone work around the bread oven attests to that. The kitchen has a large terrazzo sink under the window centred in the rear wall of the house. A door from kitchen leads out into the eixida. Another door in the kitchen leads to a covered area in the courtyard. This second door was likely a later addition. The covered section of the courtyard would have served as a pig pen or as a hen house. We have now converted this space into a dining room with two windows looking out to the courtyard. During the day the lower floor would have been in constant use as an area for working, cooking, washing and, for the children, as their play area. The upstairs would have been used only at night.

On the ground floor of our house the original flooring consisted of terracotta tiles 23 centimetres square and 4 centimetres thick laid on a skim coat of mortar laying directly on the leveled soil. We decided to conserve as much of the flooring as possible despite the wear in some areas. Some of the tiles had to be removed in order to install a new under-floor drainage system but our contractor was able to remove most tiles without damage and reuse them. Still, there was a deficit of tiles. The shortage problem was neatly solved by creating a runner of hydraulic tiles laid from the front door to the rear door. The hydraulic tiles are 15 centimetres square and added an interesting feature to the ground floor.

The second floor of our house is divided into three bedrooms. Many Casas de Cos would have had two bedrooms, and perhaps a large closet or storeroom, on the second floor. The front and back rooms originally had each a single window but we have added a second window to each room. The centre room, of course, did not have any windows but did have a small skylight set into the roof. The front room being larger would have been used by the parents’ of the family. The other room divided amongst the children and possibly the grandparents. Despite the size of the Casa de Cos it would have been a crowded place to live.

The structure supporting the second floor consists of three Catalan vaults. These vaults are the most singular architectural and structural features of the house. The Catalan vault (la volta catalana) is a traditional technique for building a shallow lightweight vault or arch. The vault over the front room is a barrel vault spanning 4.70 metres between the supporting walls and with a rise of only 45 centimetres. The vault is 6.15 metres long. Over the rectangular kitchen is a domed vault—the loads supported on four sides—where the corners are the lowest points of the vault. A small barrel vault, beside the stairs, spans the area between the two larger vaults. The term Catalan vault is somewhat of a misnomer because this building technique is found in various regions around the Mediterranean. To construct a barrel vault, rectangular terracotta tiles bricks are laid edge to edge on wooden form work. In the case of a domed vault the form work can be sometimes be eliminated. Using wooden battens to guide the laying of the tiles a domed vault can be quickly constructed. Depending on the span and loads to be carried by the vault, two or more courses of tiles would have been laid. The advantages of the Catalan vault are its light weight compared to a stone vault, the economical use of common terracotta materials and the short construction time.

A Catalan vault spanning over the front room of a Casa de Cos
 under renovation.

In our house to support the floor tiles of the second floor, ribs of ceramic brick are supported by the vaults. The result is that a good part of the second floor structure is hollow. This of course reduces the weight and also lowers the lateral loads that must somehow be carried by the supporting walls. The flooring of the second floor consists of 30 x 15 centimetre ceramic tiles laid in a herringbone pattern. Lifting the flooring tile allows access to the hollows over the vaults. With care, plumbing and electrical runs can be placed within the hollows except near the centre of the span where the space over the load carrying vault is thinnest.


A Catalan vault consisting of four layers of ceramic masonry supporting a small
 bridge.

Vilassar de Dalt has an interesting historical connection to the diffusion of the Catalan vault to North America. The engineer and architect Rafael Guastavino built Vilassar´s La Massa theatre. It was his last commision in Spain before emigrating to the United States in 1881. The theatre features a circular Catalan vault of 17 meters in diameter and a rise of 3.5 metres. It is a fine example of the technique and it inspired us to preserve and maintain the vaults in our house. The theatre is only about 150 metres from our house. In the United States Guastatavino patented the Catalan vault and used the technique on some of the most prestigious American buildings of the early 20th century including Grand Central Terminal, Carnegie Hall both in New York City and the Boston Public Library.

Not all Casas de Cos would have made use of the vault. Other examples would have floors supported by wood beams. But timber of sufficient size would have been difficult and expensive to obtain in 19th century Catalonia. (Old photographs of the surrounding mountains reveal how few trees were available in the 19th century.) Still others used a system of iron beams with ceramic infill blocks supporting the floor above. In many renovations the vaults and wood beams have been replaced by modern concrete or wood structural systems. This probably reflects the reluctance of contemporary contractors and architects from dealing with structural masonry systems.

Looking up at the structure of the second floor of a Casa de Cos.
The rough hewn pine beams support wood stringers which in turn
carry planking. The finished floor consists of ceramic tile laid on
 the planking

Originally, in our house the underside of the vaults were covered with a layer of plaster to smooth out the unevenness of the masonry. We elected to remove the plaster and expose the vaults. The exposed masonry is a testament of the masons’ skills. The ceilings are high enough that the ground floor rooms do not feel like caves. Our house faces south-east and is located on a relatively wide street so that lots of natural light enters though the windows and the glass doors of the threshold.

The roof line of the Casa de Cos is simple, a ridge over the centre of the house slopes both to the street and the courtyard. The original roofing consisted of teulada, the traditional roofing tile found throughout Spain. Both our contractor and architect agreed that it would be very difficult to remove the original teulada without damaging the individual tiles to some extent so we replaced them with new ones. Nevertheless, we did note that the contractor carefully removed the old roof tiles and trucked them away. We were happy to use modern roofing tiles if they could guarantee the integrity of the roof—i.e. that it kept the rain out.

Cross-section through a typical Casa de Cos. The front facade is
to the right. There is a vault over the kitchen, ground floor left, but
wood beams span over the ground floor front room.

As originally built, the roof of our house was supported by wood beams. The beams were essentially tree trunks stripped of bark and set onto the side walls. Scarcity of suitable timber in the vicinity of Vilassar de Dalt can be inferred by the use of some very bent logs in our house. The builder and original owner of our house would not have been too fussy about appearances. Shims were used to fill the gaps between the timbers and the underside of the roof planking. The planks carried a layer of what is essentially earth on which the roof tiles were placed. It was obvious from the time of our first pre-purchase visits that the beams would be a problem. A cursory inspection found them all to have been damaged by woodworm, some of them severely. We decided to replace them all with glue-laminated wood beams. As the old beams were removed it became apparent just how badly damaged they were. The new beams were treated against woodworm.

The loads supported by the roof beams and vaults are carried by the thick party walls (the side walls we share with the neighbours). These party walls are made of tapia, nothing more than packed mud and cobbles. Confined on either side by wood forms, moist earth is packed down with rams. Successive layers of tapia are gradually built up to the required height. Horizontal loads from the floor vaults between adjacent houses would cancel each other but still the walls had to be thick enough to eliminate the need for buttresses. During the renovation of our house when I looked at the exposed mud walls I had the impression the walls were made up of pre-formed blocks of tapia—akin to adobe blocks—cemented together with a mortar of some sort. It would certainly speed up the drying of the walls. One source that I found stated that it could take up to two years for the moisture content of a tapia wall to each a state of equilibrium. It would have made sense to use pre-dried and pre-formed blocks especially if the walls had to support the relatively heavy loads of vaulted construction. With brittle masonry vaults susceptible to cracking it would also be critical to reduce the amount of movement. Using pre-formed adobe-type blocks would help reduce movement due to shrinkage as the walls dried.

The use of tapia construction seems to have been common practice in Vilassar. I have seen other houses in town with mud walls. Certainly the workmen doing the renovations to our house were familiar with tapia walls and comfortable working with the material, for example when they made the openings for two new windows of the second floor bedrooms. However, I suspect that they would be at a loss if they had to build up a new wall of tapia, while on the other hand they were very adept with brick masonry construction. The exterior walls are thick, at the ground floor the rear wall is 58 cm thick, at the street façade it is 48 cm. From the second floor up, the walls are thinner, 56 and 41 centimeters thick respectively. I am not sure why the walls are were not built the same in front and rear but the tapia of the front walls had some larger pieces of stone embedded. The party walls, or rather the walls we share with our neighbours and carry the horizontal loads from the vaults are at least 90 cm thick.

It is important to allow tapia to dry out and then to protect it from rain and groundwater. Sometime ago we saw the result of water damage to a tapia wall not far from our house when the wall of an old house partially collapsed into the roadway. That house, which was then under renovation, had not been properly protected from the elements. After a couple of days of heavy rain a portion of the wall had been weakened. During our own renovation, removal of the old roof coincided with the April rains and particular care was taken to protect the tops of the walls by covering them with waterproof tarps. Our architect insisted that a continuous band of concrete reinforced with steel bars was added to the top of the tapia walls.

One source states that in Premia de Mar some of the old fishermen’s Casas de Cos were constructed with the ground floors below street level for two reasons. First, it helped stabilize the temperature within the house by increasing the thermal inertia of the ground floor thus making it more comfortable in summer and winter. During the day the lower floor was the centre of activity and keeping it cooler in summer and facilitating heating in winter would have been advantageous. The upper floor was used only at night. Secondly, by excavating below street level a ready source of material for building the tapia walls would have been at hand.

The bases of the tapia walls are also susceptible to moisture infiltration from soils supporting the walls. So it is also important to control groundwater near the building. In our house water leaking from the main under-floor drain likely caused some damage to the base of the wall in the kitchen. This was apparent when we first visited the house. It was obvious where the under-floor drain ran. It did not help that the original under-floor drain consisted of a rectangular channel formed from bricks—needless to say such channels leak tremendously.

The eixida, or courtyard, at the rear of the house is roughly 5 x 3.5 metres. About a third of the courtyard has a vaulted roof over it. There is a large safareig, or laundry sink in a corner of the courtyard supplied by an overhead water tank built into the corner formed by the walls. The tank would have been filled bucket by bucket and later connected to the municipal water supply. A few of our older neighbours who have lived in Vilassar all of their lives have told us that some houses on our street had wells in the courtyard. Access to these wells was shared between two or three neighbouring houses. That our immediate neighbour´s house had the well is obvious as there is a pulley wheel hanging from a bracket on the wall. A measure of how little altered had been our house can be inferred by the fact that when we bought it there was only one point of inside water supply, a cold water faucet over the kitchen sink. A shower and water closet had at some point been added under the vaulted portion of the courtyard but to access it one had to dash outside. A small electric caldera, or water heater, heated the water for the shower. Few Casas de Cos as originally built would have had inside sanitation facilities. The most common solution would be an outhouse over a dry well, or holding tank, that would be periodically emptied by a local farmer requiring fertilizer. Our house had been in the same family for most if not all of the 20th century and obviously the owners had not kept up with the times.

An interesting feature of our house is the front garden. The ownership of this small plot of land is problematic. Almost certainly it was originally part of the house but at some point it was severed from the lot and ownership passed to the municipality. The garden measures roughly 5 by 7 metres. It is very small to have served as a vegetable garden but still today there are in Vilassar similar sized gardens that supply their owner’s tables. Our immediate neighbour also has a similar space but, as far as I know, in Vilassar these are the only two houses with such an arrangement.

These 19th century Casas de Cos originally housed
fishermen and their families in Vilassar de Mar.

In other towns these small gardens were more common. In Premia de Mar the streets were laid out parallel to the sea and whole blocks of Casas de Cos were built with the front façade facing south (and the sea). Behind the house, to the north, was a garden and beyond that the eixida with a safareig, the outhouse and a fruit tree, usually an orange or lemon tree. From the courtyard there was access to the next street across which was another row of Casas de Cos. In Vilassar de Mar the streets were also laid out parallel to the sea. Again the front facades of the Casas de Cos were on the north side of the streets. However, the garden corresponding to each house was across the street to the south. In the 1950s Vilassar de Mar’s garden plots were taxed out of existence and built over with new construction that was generally higher than the Casas de Cos. I found one street in Vilassar de Mar that still retains the original arrangement of houses and garden plots, however, where once vegetables were grown now cars are parked. Our house with its garden plot in front and the eixida in the rear would have had a similar layout to that of those Vilassar de Mar houses.

Casas de Cos in Vilassar de Mar with their front gardens intact.

The Casa de Cos is a simple structure but in it we find some interesting links to Catalonia´s social and industrial history. Though they may be plain and unadorned they serve as repositories of traditional construction methods. The volta Catalana and tapia wall are no longer used but are part of the region´s architectural heritage. The very basic structure lends itself to easy upgrading, renovation and conversion. Most Casas de Cos continue in their original function, as single family dwellings, but many have been converted into offices (for example, our architect´s office in Vilassar de Mar), small shops or as workshops. Our renovated Casa de Cos is comfortable and homey. The major change that we made, add a third floor and terrace, resulted in a studio with a view of the sea. The house may be somewhat rustic with the odd dash of tiles in the kitchen or on the stair risers and treads but it has character. From the street the Casa de Cos seems to hide and rebuff attention but once inside it has secrets to reveal.