Circular insulation materials with a stronger evidence base
An exploration of circular insulation materials for the City of Amsterdam, carried out with Spaak Circular Solutions. Fifteen materials were assessed through a reduced life cycle assessment, the environmental cost indicator and building performance logic, so circular insulation choices can be connected to municipal instruments.
Fifteen materials, three preferred options
From an environmental and financial perspective, flax board performs best for roof insulation, cellulose for cavity walls and LDPE foil for floors. The exploration also shows that current assessment methods still miss part of the real story: biogenic carbon storage, actual reuse rates and health effects are not yet fully reflected.
The challenge
Amsterdam wants to renovate the existing city in a more circular way. Insulation is a practical starting point: it reduces energy demand, but the materials themselves also carry environmental impacts. This exploration helps connect material choices to renovation instruments, subsidies, loans and procurement routes.
The project assessed suitable circular insulation materials from an environmental and financial perspective, explored how these materials could be embedded in municipal instruments and made the knowledge usable for relevant market actors.
Fifteen materials
More than 35 insulation materials on the Dutch market were screened. Fifteen were selected because they are relevant now or promising for the future.
- Roof: aerogel, EPS, wood fibre board, mycelium, PIR, recycled cotton, straw panels and flax board.
- Cavity wall: aminotherm, cellulose, glass wool and stone wool.
- Floor: LDPE foil, perlite and PS beads.
LCA, environmental cost and building performance
The assessment used a reduced life cycle analysis. The environmental cost indicator combines eleven impact categories, from climate change and acidification to resource depletion, over the life cycle of each material. The building performance calculation distributes those impacts across the building lifetime and accounts for reuse potential.
The reference case was a 67 m² mid-terrace dwelling with energy label D and a 75-year lifetime. The analysis used data from NIBE, EPDs, producers, suppliers, contractors, processors and trade associations, with verification by the Amsterdam University of Applied Sciences and C-Creators.
What was compared?
Each material was assessed on CO₂-equivalent emissions, reuse potential, cost and building performance. This creates a more practical basis for choosing materials than climate impact alone.
Preferred choices
- Roof: flax board. Recycled cotton and flax board have low climate impact; flax board combines this with strong environmental performance and practical applicability.
- Cavity wall: cellulose. Cellulose has the lowest CO₂ impact and the best environmental performance in the cavity wall comparison.
- Floor: LDPE foil. LDPE foil scores well on CO₂ impact, cost and environmental performance.
Beyond the calculation method
The exploration highlights four limitations in current methods: biogenic carbon storage is not fully valued, actual reuse may differ from database assumptions, real service life can be shorter than the model assumes, and health and social effects are often outside the calculation boundary.
From analysis to implementation
The project translated material insights into possible municipal instruments: supplier lists, buyer groups for homeowner associations and housing corporations, pilots for innovative materials, decision trees for material choice and clearer guidance for contractors and renovation programmes.
Download the report
Circular renovation needs better material evidence
Insulation choices influence energy use, embodied impact, material reuse and indoor health. This project makes those choices more explicit for policy, procurement and renovation practice.