The 5th Surface
BACK 
Biochar-Enhanced Growing Medium
Biochar from local urban biomass waste - including food waste - combined, where viable, with regional biomass waste - including agricultural residues to create a lightweight growing medium.
- Urban biomass waste
- Rural biomass waste
- Combined where viable
- Converted into lightweight growing medium
Light Enough to Unlock.
Heavy Enough to Hold.
Combining a lightweight growing medium with an existing modular tray system, T5S targets a saturated system weight of:
- 70-90 kg/m² without PV
- 80-100 kg/m² where PV integration is viable
Both remain well below the ~150 kg/m² design threshold relevant to many existing roofs.
T5S targets the useful weight window: around 50-55% lighter than conventional green-roof systems - light enough to unlock more weight-constrained rooftops, yet heavy enough to support PV where viable.
BACK Underused Rooftops
Cities are running out of space. Rooftops are one of the few large surfaces that already exist but remain underused.
Many roofs - especially older ones - are structurally constrained by load. That often forces a choice between:
- PV
- Greening
- Urban agriculture
- Or simply leaving the roof unused
Even where one use is possible, combining multiple functions on the same roof can be difficult.
T5S
Use the waste problem to solve the rooftop problem - and the rooftop to create a new end market for the waste.
T5S uses existing rooftop space to create a local circular platform - no new land, no new large-scale infrastructure.
Biomass waste becomes part of the material solution to the rooftop load problem, while the rooftop becomes a new end-use platform for solutions made from that same waste.
- Uses existing underused rooftop space
- No new land required
- Connects urban and regional biomass streams
- Reduces structural load through new materials derived from waste
- Enables PV-only, green roof, urban agriculture, or agrivoltaics
- Creates a shared urban-rural circular platform
Hard-to-Abate Biomass Waste
Biomass waste remains difficult to eliminate and often lacks a sustainable, high-value end market.
The problem exists on both sides of the urban-rural interface:
- Cities generate food and other organic waste
- Surrounding rural areas generate agricultural residues
- Both need viable local pathways beyond disposal or low-value use
BACK Selected as a Top 10 Research-to-Innovation Startup
T5S was selected among the Top 10 standout startups transforming research into innovation by DWIH San Francisco and The GUILD Academy, with an invitation to Silicon Valley including exchange at Stanford University and UC Berkeley.
First Presentation at the National University of Singapore
T5S was presented for the first time at the National University of Singapore (NUS), marking the beginning of its development in the Singapore context.
Selected for Carbon13 Cohort 6, Berlin
T5S was selected into Carbon13 Cohort 6 in Berlin, joining a cohort of 80 people from science, technology and business focused on building high-impact climate ventures.
Selected for BIOECONOMY GIANTS Phase II
T5S was selected as one of 40 stakeholders for BIOECONOMY GIANTS Phase II, joining a European initiative focused on building Cooperative and Circular Bio-based Business Models (CCBBMs) and stronger value networks around underutilised biomass.
BIOECONOMY GIANTS is funded by the Circular Bio-based Europe Joint Undertaking (CBE JU) under Horizon Europe.
BACK T5S is currently looking for the following partners for pilot Living Lab development and validation in Singapore, Malaysia, Europe.
Pilot & Rooftop Hosts
- Commercial buildings
- Industrial buildings
- Institutional buildings
- Public buildings
Biomass & Biochar
- Biomass feedstock owners
- Food and organic waste streams
- Agricultural residues
- Biochar producers
Materials & Manufacturing
- Lightweight materials
- Bio-based materials
- Composite materials
- Manufacturing
Rooftop System Partners
- PV systems
- Agrivoltaic systems
- Urban agriculture
- Green roof systems
Living Lab Partners
- Municipalities
- Universities
- Research institutions
- Companies