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The Circular Bathroom - materials & resource flow in a loop

Denne idé er en del af The Circular Construction Challenge – Rethink Waste

Simon @FlowLoop
Simon @FlowLoop
8. oktober 2018

”The Circular Bathroom”

- materials & resource flow in a loop

The bathroom has the most resource demanding square meters of a home – both regarding costs during construction itself, the carbon footprint of the materials, as well as the resources required during use once the home is built. 
In order to make homes of the future more circular there is therefore a significant need for focusing on both material use as well as resource consumption in the bathroom which is at present a very non-circular construction...


”The Resource Consuming Bathroom”

Showers and toilet flushing are together responsible for almost 2/3 of a household's water consumption (36% and 27% according to DANVA). Although the bathroom is one of the home's smallest rooms, then energy alone for heating water for showers makes up approximately 25% of the household's total energy for heating (SBi).

The bathroom's small size taken into account, it is remarkable how much it contributes to total CO2-emissions during use of a home. Only about 40% of the total carbon footprint from a typical detached house is related to materials (construction, replacement and demolition)  whereas more than 60% of CO2-emissions are related to actual resource consumption in the household, primarily for heating (Realdania 2014).

The still warm shower water is normally instantly wasted directly down the drain together with 90% of the energy used to heat the water. By thinking more circular there is thereby an enormous potential for savings in the bathroom. Both concerning use of materials as well as the consumption of water and energy during daily use of the bathroom.


The concept behind ”The Circular Bathroom”

Flow Loop is a startup company that the last 3 years has focused on developing solutions, which can reduce water and energy consumption in the bathroom.

There has however continuously been a great desire to think circular materials into the concept.

Flow Loop will now contribute to further develop the idea of "The Circular Bathroom" and attempt to make circular materials and circular resource consumption go hand in hand.



The challenging wet room:

As a wet room, it is crucial that a bathroom’s wall construction is kept closed and dry so that the structure is not exposed to moisture. If the protection of the bathroom wall structure is incomplete it can often go very wrong and require extensive renovation - or complete re-construction to avoid water damage on the building's construction or an emerging health risk from the indoor climate due to e.g. mold or fungus. A new bathroom  both costs a lot of money as well as a lot of resources and the process can take a long time to complete with possible need for rehousing for many weeks.

Unfortunately, a bathroom’s materials  are not easy to reuse. Most often, bathrooms are covered with glazed ceramic tiles on both walls and floors, mounted using adhesive mortar, which often makes it impossible to get the entire tile knocked off the wall - even with the careful use of a chisel. If the tile actually comes off in a single piece, then mortar should be carefully removed before the tile in principle could be used again. However, tiles from a wet room rarely gets a desired patina since lime scale and dirt over time bind well and require thorough mechanical or chemical cleaning. Therefore traditional ceramic tiles from a bathroom are usually not suitable for circular construction.

The mounting of tiles is both a cumbersome and expensive work process. In addition, the production of traditional ceramic tiles require a lot of energy for burning and releases approx. 20kg CO2 per M2 of tile (Kellenberger, 2007). In addition to CO2 from the tile itself, comes the CO2 intensive cement and other mortar ingredients.

All of these CO2 intensive material resources are at present wasted (or at best down-cycled) when renovating or demolishing a bathroom. Often the eventual demolition of a bathroom can be caused by only a few loose tiles causing devastating water damage that requires the entire tile wall to be broken down and rebuilt with new virgin materials.


A step in a more circular direction

Flow Loop has an ambition of changing the way we currently build bathrooms and make them fundamentally much more circular, both in terms of resource consumption during use, as well as material use under construction and eventually possible rebuilding.

However, it is never easy to change the use of traditional materials and building habits - especially not a critical place like in the bathroom - but with small adjustments that build upon centuries of experience within construction principles, we hope to come a long way.

We have already seen a number of revolutionary improvements to bathroom construction in the last few decades. For example the trend towards using larger tiles has created new needs and solutions. In Denmark the linear drain has now become a new standard in new construction with both an easier workflow during construction (one even floor sloping towards the wall) and a safer solution that eleminates exposing the critical corners between floor and wall directly to water.

New innovative ways to install glass shower walls without breaking the wet room water barrier have been developed. Alternative materials have also found their way into the bathroom. Waterproof plywood boards with waterproof joints have been used for a number of years as a cheap and more sustainable alternative to mounting tiles. A large floor tile of tempered glass can now cover an entire shower space by silicone sealing it on a stainelss steel frame, thus eliminate the risk of loose or cracked tiles and preventing water from penetrating into the floor structure. It makes sense that if you can construct large waterproof aquariums this way, then you can also create a water tight shower space this way.

Further more, wall-mounted toilets with built-in cisterns have now become the preferred choice for new buildings, for amongst other reasons because of the easier cleaning. All of these incremental improvements in the way to construct a new bathroom, give us hope that the traditionally conservative bathroom design can become more circular in the coming years.



Flow Loop's existing circular solutions

Before going into details about Flow Loop’s solution for this Circular Construction Challenge here is an introduction to Flow Loop’s existing circular solutions to set the context of Circular Consumption in the bathroom.

Flow Loop is a startup that has developed solutions for reducing resource consumption in the bathroom over the last 3 years. The first product is a re-circulating shower that can save up to 85% water and 75% energy while improving flow compared to a regular shower. This is achieved by continuously micro-filtering, UV-treatment and re-circulating the still warm shower water directly from the shower floor before it reaches the drain. This way the household’s total energy consumption for heating can be reduced by approximately 20% and the household's total water consumption can be reduced by 30%.

See more on www.flow-loop.com

Flow Loop's re-circulating shower has been tested in collaboration with Water DTU over a period of 8 months where it has been documented that purified water fulfills the criteria for excellent bathing water quality. Even under the ultimate stress-test for 6 days at Roskilde Festival with two shower wagons and hundreds of daily users, the numerous water samplings from DTU, proved that the systems still provided bathing water in the best possible category for bathing water quality (in average exceeding 10 times below the limit values).


Potential circular water savings

The total water savings when using Flow Loop can reach up to approx. 50% of a household's total water consumption if the purified water from the shower is subsequently used for toilet flushing the same day. During the construction phase an additional cistern with increased capacity can be built into the shower wall, which can then be connected to the toilet’s cistern and deliver purified shower water for flushing the toilet the same day. If the purified shower water is not used for toilet flushing the same day, the water is automatically disposed directly to the shower drain, as there is likely to be additional freshly purified water provided by the shower every day.


Maintenance and circular installation

The Flow Loop shower system is designed to have very low maintenance due to self-cleaning micro-filters that clean themselves with rotating high pressure nozzles (much like a dishwasher) both before and after each shower. The system's highly efficient UV-light purifier has a life time of approx. 20 years (at one-hour daily use) and when eventually we switch to LED UV-lighting the potential life time will be much longer.

Flow Loop’s shower panel has been developed to allow plug'n play retrofit installation without breaking the crucial wet room water barrier itself. The panel has a customizable front panel where any tile material is easily replaceable in a stainles steel cassette with a silicone seal allowing separation and circular use of materials.


Integrated installation

Flow Loop is currently developing a new solution for installation integrated into the the shower wall itself, during construction of a new bathroom with eg. linear wall drains (the new standard for construction in DK). This will allow freedom to get the system integrated inside the wall together with the wet room membrane and behind a protective tile material.

Since wall-mounted toilets are also the new standard in new construction, it makes sense to build both the toilet’s cistern as well as an additional cistern for storing cleaned bathing water into the same wall curing construction. A  patentable solution ensuring that there is no risk of any leaks in the system inside the wall structure is under development. In fact, this solution is more secure than not having the system installed, as any leak inside the wall structure become harmless.

Small leaks from fittings or pipes in the wall may otherwise cause slow but devastating water damage that is usually not detected before it is too late with mold, rot and fungus in the wall structure. Once this is the case then the entire bathroom including wall construction must be broken down and rebuilt with new extensive costs and waste of material resources as a consequense.



A more circular tile solution

Traditional glazed ceramic tiles have a carbon footprint of more than 20kg CO2/m2. A bathroom of e.g. 5m2 would normally have at least 20m2 of tiles, adding up to at least 400-500kg CO2 excluding the mortar used.

In addition, it is a long and difficult process to set up wall tiles, and neither tiles nor adhesives can after demolition be used for much else than being crushed and downgraded to eg. a filling material for road construction.

In short, current bathroom materials are not the most efficient use of energy intensive resources. Flow Loop has therefore examined which more circular materials could instead be used to protect bathroom  walls on top of the wet room membrane.

Coloured glass tiles have been used for centuries if not millennia for wall decorations and mosaics.We want to revive the glass tile in a modern and innovative version with huge CO2 savings.

In Denmark there are about 3,5 million buildings with a total window area of approx. 60 million m2. The Danish Energy Agency estimates that approximately 4.5 million square meters of windows in Denmark. Of these, the majority are replacing existing windows. Therefore an estimate is that about 3 million m2 windows end up being recycled each year. The majority of the glass panes are  crushed and melted into new glass products, but a large fraction still ends up as landfill.


Laminated glass

Laminated glass is two or more layers of glass panes glued together with an adhesive film to create a safety glass, so that eg. a car’s windshield does not splinter in an accident. This transparent film is normally made of BVP, wich is an expensive and environmentally problematic material

The Danish company Shark Solutions has the last decade specialized in a solution for seperating laminated glass so that the laminating film layer can be recycled. Since 2012 they have diverted over 6million m2 windshields and building glass from landfills where they would otherwise would take many thousands of years to decompose.

If the laminated glass does not need to be transparent, then other unproblematic adhesive films can be used instead. For example frosted or coloured films could be used between two layers of 3mm thick window panes to create a very strong 6mm thick tile material, where the coloured, textured or patterned material is sandwiched in the middle, creating 3D shadow effects from eg. droplets through the first 3mm layer of glass.


Glass tiles with huge CO2 savings

In 2014 RealDania built a test house in Nyborg with recycled glass panels as a climate screen outside the roof structure of the building and the outer walls as an overlapping glass surface.

This overlapping principle has been used for centuries with slate and even back in the Viking age with overlapping shingles of wood, still visible on the Norwegian stave churches.

According to Dansk Byggeri, approximately 20,000 new homes are needed annually in the coming years to meet the growing population's needs. There is already more than 2.6 million homes in Denmark that have their bathrooms remodelled in average every 20 years. This means that in Denmark potentially 150,000 bathrooms are yearly either built or rebuilt.

If glass can protect the vertical outer wall construction of a house from of rain, snow and moisture, using overlapping glass panels then glass must also be able to provide it inside the house's bathroom to protect the structure inside the wet room membrane. Instead of gluing burnt and glazed ceramic tiles onto the wet room membrane with adhesive cement, which makes it impossible to reuse the materials in a bathroom again, it must be possible to develop an intelligent mounting system that allows disassembly, separation and recirculation of materials. Large fish tank aquariums have glass panes sealing the water using silicone. If the glass breaks then the silicon can just be cut off and removed using  a simple stanley knife to recycle the glass. This principle could also be used in bathroom construction.


Installation of laminated glass tiles

Instead of using new ceramic tiles in a new bathroom with a carbon footprint of approx. 20kg CO2 /m2, we can CNC cut and laminate 2 layers of standard 3mm window glass with a carbon footprint of only about 1,8kg CO2 /m2.

This is a factor 10 reduction of CO2 for materials under construction – but when looking at LCA of the savings during rebuilding and eventual demolition, then savings will be significantly greater as all the materials can be recycled either as they are or are recycled separately for new products versus only down-cycling of traditional ceramic tiles and mortar/cement.


These tiles can have any kind of colour, pattern or frosted texture etc. because of the protected adhesive film layer in the middle. This gives full freedom to create new tile designs, and as trends change over time the glass tiles can be seperated into two again and have the adhesive film layer replaced (recycled) with a new design. This way you are not stuck with tiles that were trendy 40 years ago as is the case with bathrooms from the 70’s.

Many house buyers today choose to redo an entire bathroom because of an outdated tile design.

We want to make an easy way of updating your tiles without extensive and expensive rebuilding.

We therefore want to create an innovative mounting system using extruded profiles of recycled plastic (eg PE or LDPE) in neutral mono-chrome variants (black/grey-scale).


These extruded mounting profiles mimic a traditional 6mm tile grouting, but function as an easy installation rail that holds the laminated glass in place and protects both the (sanded/smoothed) glass edges as well as protecting the water membrane from water and moisture. This is ofcourse crutial that moist cannot go past the membrane via eg. the screw holes holding the rail with overlapping glas tiles. The carefully designed and extruded plastic profile can have a thin layer of silicone to ensure a  perfect seal around the glass edges. The plastic grout also serves a an easy place to screw in bathroom accessories without having to drill first and without breaking the membrane (short screws). The specific design must be thoroughly tested for the strength and density of holding the glass tiles and protecting the water barrier.



Production of laminated glass tiles

Most windows today are at least double glazed. This means that when the glass is still in the window frame you have two layers of 3mm glass that have to be removed. This is tedious manual work that is normally not feasible. Using automated industrial techniques like electric suction cup lifters, the window frames can be precisely placed on a CNC machine, where a fast glass cutting blade replaces the normal routing drill bit.

Once the glass is scored on both sides (both layers of glazing), the CNC machine can quickly tap on top of the scored lines making the desired glass tile size pop out of the frame and at the same time hammering the remaining glass strips in the frame out for recycling as cullets for remelting. This proces also makes it easier to recycle the window frame material (wood, aluminum, plastic) without the glass fraction.

Even the traditional Danish window frames (Dannebrog) are large enough to cut out large tile sections to be laminated into eg. the standard size 30x60cm glass tiles.  

Including the extruded profile of recycled plastic the re-circulated glass tiles have a factor 10 reduction of CO2 for the material under construction compared to ceramic tiles and mortar/cement adhesive.

The savings in the tile’s total Life Cycle Assessment will however be significantly greater as all materials can be recycled either as they are or are recycled individually to new products.

In addition, there is a considerable time saving on setup and, consequently, an economic savings at both set-up and again by removal of seperated circular materials.




Competence needs

We need competences from the construction industry that have an overview of current practices and requirements in bathrooms, such as plumbing, wet room protection, etc.

In relation to materials, we need competencies in resource utilization, practices in separation of primarily window glass and various plastic fractions.

In terms of production, we need expertise witnin CNC scoring/cutting of glass panes and subsequent treatment of edges and surfaces (lamination, sanding, sandblasting etc.).

In addition, we need experience and expertise in shredding, colouring and extruding recycled plastics.




We expect that participating in CCC can help us get the right skills onboard to develop both the process of upscaling CNC cut glass in an innovative combination with extruded recycled plastic for easy assembly, removal and separation for subsequent circular recycling.


We anticipate this project will result in a number of new solutions for a circular glass tile system that significantly reduces the carbon footprint from the bathroom's materials and opens up new opportunities both in recycling the bathroom resources and reduce the waste of ressources during remodelling and demolition.



Time Plan

The first periond of months will be investigating the possibilities of creating laminated glass tiles using different adhesive films with different strengths, textures, colours etc.

The crutial investigation of the mounting rail can take place before the infrastructure for plastic recycling and extrution is in place. Traditional plastic extrution techniques can be used to make sure the the functionality of the plastic profile is sufficient to support the tiles and keep the wall safe from moisture.

Once the concept is thoroughly tested and proved sufficiently functional under extreme circumstances, then the technique for automization of the CNC cutting and removal of the window glas can be optimized. This would include using electric suction lifters and compact CNC cutters/hammer wheels mounted with suction cups.



Flow Loop resumé:  

Flow Loop was founded in 2015 as a result of a master thesis in Sustainable Design at Aalborg University Aalborg, Cph.

Flow Loop shower panel was selected for the following accelerators:

-       Climate Launchpad 2015

-       Danish Tech Challenge 2016 at DTU

-       Accelerace 2017

-       EON Agile, Malmö 2017

-       Green Tech Challenge 2017, CBS

-       Climate KIC 2017&2018

The Flow Loop shower system has been tested at Water DTU over a 8month period to document water quality which is confirmed to be ”Excellent” - the best possible category for bathing water.

2 shower wagons with Flow Loop showers were stress-tested at Roskilde Festival 2018 in collaboration with Innovationsfund Denmark and DTU.  

CV Simon Kolff:

2018 Awarded Innobooster funding: 3 employees

2018 Climate KIC phase 2

2017 Climate KIC phase 1

2017 Accepted at EON Agile accelerator

2017 Accepted at Accelerace

2016 Accepted at Danish Tech Challenge, DTU Lyngby

2015 Founder of Flow Loop

2013-2015 MSc. in Sustainable Design, Aalborg University, Copenhagen

2007-2013 Independent design consultancy with focus on Sustainable Solutions

2007-2008 Teacher in Sustainable Entrepreneurship, Vestjyllands Højskole

2001-2006 BA Industrial Design, Design Academy Eindhoven, Holland

2000-2001 Aarhus School of Architecture


Awards and prizes:

Flow Loop’s shower panel has previously been awarded a number of awards and grants within different accelerators:

- Porto Water Innovation Week (1st prize): 100.000DKK

- GreenTechChallenge 2017 (2nd prize)

- Innovation Fund Denmark 450.000DKK

- Eon Agile €30.000

- Climate KIC €45.000