Left over straw used as building material, large CO2 reduction potential

The leftover straw used by Biobuilds to build sustainable houses blocks in the walls the equivalent CO2 emitted by thousands of flights all over the world.

A 10 sqm Biobuilds’ passive house straw wall stores 900 kg of CO2, equivalent to the amount released by a midsize diesel car in 70.000 km or by a flight from London to New York per one passenger 0,9 tons of CO2 per passenger, emitted by a plane from London to New York, can melt 6 sqm of Arctic sea ice 39% of global CO2 emissions are linked to the building conventional industry, using harmful materials.

Left over straw used as building material, CO2 savings

Burning the leftover straw was a widespread practice until the ‘90s, theoretically prohibited in some countries, discouraged or allowed by permit in others. Nowadays the situation has changed 180 degrees and the straw, from a waste and useless material, is getting a new sustainable and major new life in the building segment.

It’s well known that 39% of global CO2 emissions are linked to the conventional building industry. Yet, this situation makes a spectacular switch, offering solutions to remove CO2 from the atmosphere. Straw naturally sequesters carbon in grain, and this stored carbon has to be supplementary blocked in the building structure, hence removing it totally from the environment. The figures are amazing.

The straw pressed into the wall wood structure blocks around 90 kg of CO2 per sqm. That’s equivalent to the amount of carbon dioxide released by a midsize diesel car in 70.000 km or by a flight from London to New York per one passenger.

Not quite a UFO or a space capsule, but just as impressive as them. Tell us where you want to build your house, and whether it’s in the heart of the city or on a hilltop, we’ll land the Module right on your site. #Biobuilds #modular #sustainable #tinyhouse pic.twitter.com/vPuViW6D01

— BIOBUILDS (@BIOBUILDS_) October 21, 2022

Given that the biggest straw wall produced by Biobuilds is 12 m long and 3 m high, it will remove from the atmosphere 3.240 kg of CO2. Moreover, being 90% organic and biodegradable, the decomposing of these walls takes only one year and a half. Translating all the above calculations to a midsize house (with a footprint of 120 sqm) means that only exterior walls on a level can store no less than 12.5 tons of CO2.

The RIA House built by BIOBUILDS in Romania has been certified by the Passive House Institute in Darmstadt, Germany, with a heating and cooling energy demand of only 2 kWh/(m²yr). Therefore it becomes the most efficient passive house in the world, produced with series production technology.

According to Passive House Institute certification, RIA House has a space heating and cooling energy demand of only 2 kWh/(m²yr). It’s an outstanding performance considering the required standard value for a passive house is 15 kWh/(m²yr) and taking into account that only few houses in the world fall below the value of 5 kWh/(m²yr). Furthermore, some of them are only prototypes who cannot be replicated at mass production level.

On this occasion, BIOBUILDS CEO Alin Muste said that “It’s a great satisfaction that the whole house is not just a house where I live, but it is a project that requires a lot of time to invest and the system we have used can be reproduced. More precisely, in the future we will produce and build houses with this system just as energy efficient.”

The RIA House is a duplex house and has a gross area of 360 sqm. It uses a straw panels system, entirely developed in-house by BIOBUILDS, which means wood structure prefabricated walls using straw as insulating material. Furthermore, all materials used are organic and have been chosen to have minimal o or zero emission of volatile organic compounds (VOCs), providing a comfortable and healthy indoor climate.

About the Biobuilds’ straw walls production

Due to state-of-the-art technology the factory is one of the first in the world producing negative carbon footprint walls at a semi-finished quality level, rolling off the assembly lines ready to be assembled on the site. The straw walls are compliant with the Passive House Institute standards – U value of 0,089 W/(m2K) -, but also integrate a high level of quality. For trimming the inserted straw insulation, has been developed an uncompromising precision system, which assure a nearly flat straw surface of the trimmed straw. This provides ideal conditions to mount the next layer, and thus an optimum airtightness.

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