Building with straw is a real possibility with examples of homes in various parts of the world, that since at least 2 centuries demonstrate the effectiveness of straw as building material.
Towards the end of 1800 the first methods of packaging and the creation of the strawbales, with straw compressed in a rectangular shape, allowed the pioneers of Nebraska the use straw in form of giant building blocks. The use of straw allowed to reduce and sometimes entirely replace the wood, allowed reduced construction times and better insulation properties.
Currently there are three main systems of building with straw.
In Method Nebraska straw bales are load bearing, positioned in horizontal courses like big bricks. The floors are linked and compression damage to the walls. The whole thing is anchored to the foundations.
Other methods are mixed, with wooden frame and infill bales. The types of structure are beam-column, platform framing or balloon frame. These are typical methods of building culture amerizana and consist of walls made of planks and adjust pitch short, to form load-bearing walls. They differ only in the position of the floor, the platform that is positioned between the walls, anchored inside the balloon.
There is then a little-used method, said method Matrix, in which the bales of straw are positioned in vertical columns of mortar between the pillars. This method is not recommended for the type carrier, for the intensive use of cement and labor, for the matching between risky straw and cement.
Why build with straw?
The straw is an agricultural waste product, used primarily as animal bedding and base for mushroom growing.
As a building material possesses phenomenal characteristics: a single price, handy, phone and heat insulation, healthy.
From an ecological point the material is widely distributed and does not need processing (reduced energy cost), also in the use phase, that a mere level of calculation accounts for 50 years, the excellent insulating power reduces the emission of CO2 necessary to heat the home.
It consumes a house of straw?
The thermal conductivity value of the straw is around 0054 W / mK, completely aligned with the most common natural insulation in the building industry. The thickness of a baletta of straw is of 0.48 m. It follows that the transmittance (the insulating power) of a wall of bypasses (0.054 / 0.48 =) 0.11 W / mqk, corresponding to a wall to the energy standard passive house.
Assuming a wrapper around a good size and homogeneously isolated, so no “holes” energy, we can estimate an annual consumption of 15kWh / (m² * a) (= 15 kWh per square meter per year). Assuming a house of 150 sqm net consumption will be: 15 × 150 = 2250 kWh / MQA
These can be produced with 5.8 kWp of photovoltaic panels which feed a heat pump, or by 11q of wood which feed a stove.
(Data underlying the calculation: COP PdC: 3.5; PV efficiency kWh / kWp: 110; calorific wood: 2.1 kWh / kg)
The straw walls involves crooked and irregular?
The result of houses Pagli comes from the construction technique adopted by the creative and the client. There are special constraints and those who want it can have straw walls shaved as the most modern fashion store. Of course in most cases, customers who want natural surfaces, the more moves or even personalized.
How much does a house with straw bales?
The costs are minor compared to a house in cemebto concrete. but must be considered that the cost of insulation and brick (the straw that usually replaces) can account for 20% of total costs, while the finishing touches of a home affect at least 50% of costs. E ‘then only 1/5 of the total costs that the use of straw goes to affect with substantial savings.
If a house costs 1100 € / sqm * Commercial and straw saves 80% on 20% of total costs, the savings with the straw is (1100 × 0.8 = 0.2 *) 176 € / sqm .
(* Costs are approximate and may vary greatly according to location)
Another is to consider instead the additional potential benefit is that by easy DIY. Constructing “do-it-yourself” means to save on labor and VAT.
How long does a house of straw?
The houses of straw, the same way as those raw earth, can last indefinitely.
Only two things they need: a good pair of boots and a hat with wide brim.
The straw-but in general all-natural materials fears the water. The walls must be protected from rain by a good agetto gutter and base against the earth and water ski. Obviously, avoid building homes in flood zones straw (see under: construction on stilts).
To explore the theme duration straw house also read this article in which I have extensively addressed the issue:
The straw is resistant to fire?
It’s funny that no one asks if a wood roof is fire resistant. A house of straw plastered burns as a wooden house. In any case, the straw is never left exposed.