Strandek® eValue

Strandek® eValue is an in-house, estimated calculation intended to approximate the savings and benefits provided to customers from the date we started counting. It shows why a warm-roof design is usually more efficient to heat than a typical cold-roof design. It is not a performance certificate, not SAP, not a life-cycle assessment, and not evidence of savings achieved on completed contracts.

Illustrative warm-roof versus cold-roof heating model. Assumes no skylights or roof windows. Not measured savings.

Why a cold-roof benchmark
Warm-roof designs offered a significant insulation upgrade on the older cold-roof way of building: insulation above the deck rather than at ceiling level. That is the difference this page is meant to show. The cold roof is a fixed comparison case. It is not always what was on the building before. Roofs Strandek replaces may already be older warm roofs or other constructions. In those cases the extra heat, cost and CO₂e difference would be smaller, sometimes much smaller.

Skylights and roof windows
The model assumes no skylights, roof windows, lanterns or similar openings. The deck is treated as a continuous insulated plane. Many real roofs have these openings. Omitting them overstates heat retention compared with a typical installed roof.

What the model does

  • Case A: typical Strandek® warm flat roof (insulation above the deck).
  • Case B: typical cold flat roof (insulation at ceiling level).
  • Area: one total of flat-roof area installed. Individual thicknesses, occupancy and heating systems are not used.
  • Openings: none. No skylights, roof windows, lanterns, upstands or outlets in the calculation.
  • Factors: published UK average kWh and CO₂e conversion factors and a stated unit rate for heat. National averages, not utility bills.
    [Before publish, insert: factor source, year, p/kWh.]
  • Scope: in-use heating only. Embodied carbon of materials, transport, installation and disposal is excluded.

What the numbers are
Mass of equivalent CO₂, heating bill costs and energy saved are outputs of this single illustration. They are not “already saved.” Total cumulative guaranteed years is separate: the arithmetic total of guarantee lengths across more than one contract. It does not extend any customer’s cover beyond their own guarantee wording. It is not how long one roof will last.

What we do not claim
No claim that Strandek, the roof, or the company is “low carbon”, “sustainable” or “environmentally friendly” as a whole. No claim that your bill will fall by installing a Strandek flat roof. No figure on this site is an offer, quote or forecast for a named address.

Your building
Only a survey that uses that roof’s area, build-up, skylights or roof windows, and use can support a site-specific figure.