Ecobricks & Flamability

Ensuring Ecobrick Fire Safety

“I want to build with my ecobricks, but I am worried about what would happen to them in case of fire.  What do you guys advocate for ecobrick fire safety?”

– Amanda, UK 

Dear Amanda,

Thank you for your question. The issue of ecobrick fire safety is an important one– and rightly so as plastic releases toxic fumes when it burns. However, the risk of ecobrick flamability is often overestimated due to misconceptions of how ecobricks are used. Traditional bricks and ecobricks are not the same thing, and they are used in very different ways.  I use ecobricks for my garden and my furniture and I am honestly more concerned about my traditional furniture catching fire! 

So let’s take a look at the issues…

 caFoamAs we all know, plastic in the wrong place is toxic. Especially if it is in a fire!  When plastic burns it releases all sorts of nasty chemicals and fumes.   And so too when it degrades in other ways.  The goal of securing plastic from degradation is the reason why we are ecobricking aterall!  Likewise, this is the same pursuit when building with ecobricks.  The GEA has thus developed best practices for making ecobricks and for building with ecobricks so that our constructions safely and securely contain the ecobricks for a long long time.

Of course, it is helpful to remember that given the right conditions, everything burns.

When we build with wood we do so attentive to the various properties of wood and the conditions in which it will start to burn. When we build with ecobricks we do the same:  we build in ways that minimize or even completely remove the risk of fire.

An ecobrick that is densely packed is solid plastic and very difficult to set a light.

The first step in fire safety is ensuring that the ecobricks that you use are packed to the proper density.

The GEA best-practice guideline is to pack ecobricks to the minimum density of 0.33g/ml. This means a minimum of 200g for a 600ml bottle, and 500g for a 1.5ml bottle. By packing the ecobrick tight to these specifications, the amount of oxygen in the bottle is minimized. This makes it much more difficult for an ecobrick to catch on fire, than say a bottle loosely packed with plastic.

In fact, a properly packed ecobrick is almost impossible to light on fire!  Engineers test material flammability by holding it to an exposed flame.  Foam or polyester lining with catch fire in a few seconds.  Try holding a densely packed ecobrick to a flame.  It won’t catch fire for more than 30 seconds. 

In this way, a module made of densely packed ecobricks is far less flammable than an upholstered foam or Dacron filled mattress or couch!

The second step is ensuring that you are building properly with your ecobricks. The GEA’s recommended building method is with earthen mortar. In this way, ecobricks are laid horizontally in cob (a mix of clay, sand and organic binder). For foundation, the ecobricks are half laid in cement and half in cob. There is typically a 3-5cm space of cob mortar between the bottles. When walls are built this way, they are virtually impossible to set on fire.

Cob walls have been known to stay intact long after wood beams and wood floors have turned to ash. For absolute fire safety, you can opt to cover the exposed caps and bottoms with an earthen or cement render.

Our colleagues in South Africa have done some experiments with ecobrick earthen walls and fire. You can see the results of their tests here…


A A Travellingtoes production fimed by Tarryn Jolly – “This is our 3hrs burn on timelapse. Take a look & see for yourself… I’ll dig away the bottom of the wall where the fire was concentrated & we’ll inspect the bricks together. The wall at the base baked hard and clay like in the fire, the back of the wall (out of vew of the camera- was also kept burning) but was not hosed down till all the cob plopped off so the ecobrick “reveal” will be easier; less mud to clear”See the video on Facebook

Finally, please note that contrary to popular assumption, the vast majority of ecobrick applications are for non-structural applications– like gardens bedding, playgrounds, and outdoor benches.  These applications not only have extremely low flamability, the risks of their catching fire (i.e. collapsing or turning into a blaze) are far less than that of a structure.  Afterall, a garden bench is pretty easy to get away from!

Earth and Ecobrick garden bench are an easy application that reduces fire risk to nil.

The recommended GEA ecobrick applications are small, outdoor, and non-structural. The vast majority of ecobrickers put their ecobricks to use as densily packed, small scale modules or as green spaces. Modular applications, have a low flamability compared to traditional furniture.  With outdoor ecobrick green spaces, their flamability is almost nil and the dangers of their catching fire is minimal (see the 3hr fire test by Waste-Ed above) .

Thank you again for your question.

Thinking about the potential end-life of our ecobrick in fire, is an essential part of circular design.   It is a good reminder of why we are ecobricking in the first place: Plastic can be toxic and dangerous!   We thus take responsibility for it and sequester our plastic inside an ecobrick. When it comes to building with ecobricks, we are doing the same thing.

We want to build in such a way that the ecobricks are safe and secured indefinitely from all forms of degradation — especially fire — so that years, or decades, or centuries from now, the ecobricks can be taken out, and put to good use again and again.



Burning Plastic Releases Toxic Fumes

Depending on the type of plastic being burned and the temperature, carbon dioxide, dioxins, carbon monoxide and various trace toxins are released. To prevent plastic from being  burned locally or industrially incinerated is one of the important reasons we ecobrick.

What Not to Do

When putting your ecobricks to use there are some simple guidelines to keep them fire safe.

  • Avoid wrapping them in flamable materials
  • Avoid taping your ecobricks together
  • Avoid using low density ecobricks
  • Avoid using empty bottles along side ecobricks
  • Follow the GEA guidelines on recommended ecobrick applications


One of the core concepts of ecobricking is to secure plastic inside a bottle and inside a construction to keep it from degrading (or burning!) for the next thousand years.

Plastic Sequestration