Life Reusing Posidonia

Life Reusing Posidonia

IBAVI arquitectes
Sant Ferran, Formentera, Spain | View Map
Année du projet
José Hevia

Life Reusing Posidonia

IBAVI arquitectes en tant que Architectes.

Life Reusing Posidonia is a Climate Change Adaptation Project financed by the European LIFE + program for nature conservation projects.



The main objective is to improve habitability conditions in dwellings and provide regulators and public bodies with contrasted data to decrease the consumption of resources and to grow in comfort.


The data has been obtained by evaluating a prototype building of 14 public social dwellings on a rental basis promoted by the Balearic Social Housing Institute (IBAVI) and its comfort has been monitored with the collaboration of the University of the Balearic Islands (UIB).


The documentation is open source and freely available on the web


The project links Heritage, Architecture and Climate Change with the aim to recover the local resources as a cultural approach in the contemporary research for sustainable solutions.


Traditional architecture has been a constant reference, not for its forms, but as a way of working. By doing so, we look for the available local resources: the junipers are now fortunately protected. The sandstone quarries (marès) have been depleted. Therefore, we only have what arrives by sea: Posidonia. So we propose a shift in approach which has been applied to every single part of the building:

“Instead of investing in a chemical plant located 1,500 km away, we could invest the same amount in local labor, who should lay out the Posidonia to dry under the sun and compact it by hand. Sea salt acts as natural biocide and is completely environmentally friendly.”

The use of dry Posidonia as thermal insulation reminds us that we do not live in a house but an ecosystem.



1. To demonstrate:

The viability of constructing the prototype with an additional cost of 5% over the usual price of the IBAVI social housing buildings.


2. To reduce:

- 63% of CO2 emissions during the construction of the building.

775,354.6 kg/CO2 have been avoided. Calculation performed through the TCQ program of ITEC.


- 75% of useful energy during the lifetime of the building.

Nearly Zero Energy Building (nZEB), with emissions of 2.8Kg CO2/m2 and maximum consumption: 15 kWh/m²/year (17,226.30 kWh/year). The average thermal comfort measured in situ is 21ºC in winter and 26ºC in summer.


- 60% water consumption.

Maximum limit 88 l/person and day. Average consumption based on the tenants’ bills.


- 50% waste production during the construction phase

Statistical production 70.36t. Actual production 33.38t.



All the dwellings face two directions and cross ventilation thanks to the layout of the living/dining room and kitchen in a Z shape and a bedroom at each corner.


In summer, cooling is solved passively by taking advantage of sea breezes. All windows that receive solar radiation have sun protection. Cables have been arranged on the façades to facilitate the growth of deciduous climbing plants.


In winter, passive climate control relies on low-temperature radiators fed by a 90 kW centralized biomass boiler that also produces the hot water.


The organization of spaces and formal decisions have been the result of knowing the advantages and limitations of natural materials, which are more fragile. This fragility has become a design opportunity.

Material Used:

1. Marès sandstone from cas Busso quarry

2. Tiles baked in biomass mortar kilns by Can Soler

3. Bricks baked in biomass mortar kilns by Can Mascaró

4. Aerial lime by Unicmall

Crédits de projet
Execution management
Environmental consultants
Fiche technique du produit

Aerial limeUnicmall
Fiche technique du produit
Aerial lime
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