WATERPROOFING FOR THE CONSERVATION OF BUILDINGS HAS FEW FOSSIL-FREE OPTIONS
With regard to waterproofing for flat roofs, 85 percent have bitumen-based waterproofing in the Nordic region. Nordic Waterproofing also manufactures EPDM rubber membranes and offers PVC and TPO plastics. Together, these four materials accounts for 95 percent of all building waterproofing. Currently, there are no materials at the same cost level based on completely fossil-free alternatives.
The most important inputs in Nordic Waterproofing’s production are bitumen, polymers (rubber compounds and plastics), environmentally certified wood and plants.
Bitumen – a residual product …
Bitumen is a residual product that follows in the industrial refining of crude oil when producing different fuels. Bitumen production requires thus a lower energy consumption in the production itself, however, heat energy is required in the processing of waterproofing products.
… with a long-life cycle …
Today’s bitumen-based waterproofing, blended with elastomers and polymer for increased flexibility, has a life cycle of up to 50 years, where design and installation also affects. When renovating the waterproofing, the old layer normally is kept, and a new layer is added.
… and which doesn’t harm man and nature
As bitumen is a hydrocarbon not intended for combustion but for use in structural materials, no greenhouse gases are emitted. The remaining constituents of bitumen-based waterproofing (fillers, polymers, slates, sand, etc.) are either inert (not inclined to form chemical compounds) or have low propensity for chemical reaction. This means that they pose minimal danger to man or nature throughout their life cycle, provided that it isn’t burnt. Bitumen is insoluble in water, non-biodegradable and therefore the ideal material for collecting and holding water (collection ponds, irrigation water, polluted water etc.). In order to reduce use of polyester in the liners, a large part consists of recycled polyester from PET bottles.
Reduced material utilization…
Product development is also focused on reducing the thickness of roofing felt (and thus the amount of bitumen) while maintaining function through better blending recipes.
… and increased proportion of sustainable materials
Sustainable materials are a growing part of Nordic Waterproofing’s operations. Both green infrastructure and wood-based building elements have a positive environmental effect due to their CO2-binding properties. Wood as a building material is a natural raw material that has a significantly lower emission level compared to other building materials.
Green infrastructure contributes to biodiversity while protecting the underlying waterproofing membranes, the building gets a better insulation against extreme temperatures and absorbs some of the city’s noise, dust and air pollution while improving both the micro and macro climates. Green roofs also act as barriers in large amounts of precipitation. They can absorb up to 50-80 percent of the precipitation, which reduces or delays the runoff of rainwater to the stormwater system. Growing plants for green infrastructure also requires no major energy consumption. In addition, biochar is used as a nutrient in the crops. It has been added from Vegtech’s bio-based boiler through so-called pyrolysis.
Reduced CO2 emissions are also possible in bitumen-based products. Nordic Waterproofing’s Finnish brand Kerabit has developed Kerabit Nature. Its fossil bitumen has been partially replaced by bitumen extracted from tall oil, CTO. The positive CO uptake through the tall oil raw material makes Kerabit Nature CO-neutral (bitumen already has low 0.2 kg CO equivalents / kg) Kerabit Nature is available as for both top and bottom layers.
Development is also taking place for application of roofing felt without gas burners, which both reduces CO2 emissions and reduces the risk of fire.
Roofing felt is normally left on the roof when applying with a new layer during renovation. NWG’s subsidiaries also have agreements with recycling companies that recycle bitumen to be used for road paving. EPDM rubber can only be reused as a filler material as it is vulcanized and cannot be melted down.