Examples ofthatched houses, legislationreference and all useful information on sustainable straw construction. Advantages and disadvantages of straw. Prices and news in green building.
Just like theraw earth, even the straw is carving out some space in thegreen building. When it comes tothatched house, the collective imagination falls on the small straw house of the tale of the Three Little Pigs: nothing so precarious! Therethatched houseoffers high living standards both in terms of comfort and energy efficiency, these pluses, however, are reflected onconstruction costswhich are currently higher than in a conventional house.
How much does a thatched house cost?Prices per square meter differ on the basis of many variables, if you want to estimate a merely indicative average we are talking aboutpricesper square meter between 1,200 / 1,600 euros. If we talk about self-construction, however, the savings increase enormously: if well designed, onethatched houseself-built using top building products, it can cost 700 euros per square meter.
Straw house: legislation
InItalythethatched houseshave now been a concrete reality for at least six years. Therestrawhas become a building material in all respects, suitable for bothrenovationthat of designing new buildings.
In fact, with straw, construction companies are able to produce a large number of finished or semi-finished products, the most common being the panel for the cladding of the load-bearing structures.
For now, thelegislationreference only provides that thestrawused must be flanked by an alternative load-bearing structure (typically a wooden skeleton): this is a prescription legislation because for technical purposes, according to experts, it could also do without it.
Please note: the Italian technical legislation of 2010 provides thatthatched housesthey must be built from an alternative load-bearing structure made of reinforced concrete, steel, wood or brick. Straw is therefore not considered a self-supporting material. In the field of green building, straw is often placed side by side with wooden structures. Using alternative structures to straw it is possible to create buildings up to 7 floors in height. Thislegislationis typically Italian because the use of thestrawlikecarrier materialforbuild houses and buildings up to 3 stories high are built without using any alternative structures.
Remaining within the scope ofregulationsisread, for the construction of straw houses or for the renovation using straw panels, no particular procedure is required by the end user who, forpermissions, will have to follow the common bureaucratic process for all constructions.
Straw houses: advantages
Straw is a highly breathable material, it is an excellent thermal and acoustic insulator. Straw walls plastered with clay and natural lime are not only virtuous in terms of environmental sustainability but also highlyinsulatorsand excellent for ensuring high energy performance of the building.
Talking about soundproofing, a 45 cm thick straw wall, plastered with a thickness of 35 mm of clay, is able to guarantee a noise reduction of 55 dBa (weighed decibel). Talking aboutthermal insulation, the same straw wall described above, as reported in Certificate Z-23.11-1595 DIBT, DE, sees values far higher than a wall of light porous bricks with insulating mortar plaster, the dispersion of thermal energy is 3.5 times lower!
The needle of the balance still hangs onthatched houseswhen it comes to anti-seismic sealing: seismic action finds the best answers when the building structure is flexible, the straw is able to absorb vibrations because the constructions are light and flexible, all of which suggests its greater resistance than the classic ones brick construction.
The straw, contrary to what one might imagine, does not retain moisture andthatched housesthey do not require special works bymaintenance.
Straw houses: examples
How long does a straw house last? To answer this question, I useexamplesof buildings already present. The first documented straw house dates back to 1896, built in Nebraska (United States), the house is still inhabited and in excellent condition.
Other examples ofthatched houses, Italian, are: the Venetian house designed by the architect Jimmi Pianezzola, the beautiful one thatched house Tuscany (Grosseto) by the architect Maria Luisa Bisognin and, finally, the terraced houses in the photo above, built using local straw and load-bearing structure given by lime and hemp (hemp bricks), on a project by engineer Giovanna Nardini and the 'architect Michele Ricci. The photo in the middle of the article shows the interior of one of the rooms of the thatched terraced house.
For the sake of completeness, I would like to point out a video of a service broadcast on Rai Tre, precisely on the theme ofstraw construction.