Livewest – Trewyn Flats

Trewyn Flats
Location: St Ives
Funding: SHDF & Client

Trewyn Flats are a group of 16 flats, situated over two floors and connected by multiple corridors, in St Ives, Cornwall. VOR group were engaged to carry out full PAS 2035 services on the dwellings.

VOR carried out:

  • Archetype assessments  
  • Retrofit assessments  
  • Energy modelling  
  • Retrofit coordination  
  • Retrofit design  
  • Planning application and regulatory consents  
  • Moisture modelling  
  • Thermal bridge modelling 

After the initial desktop assessment VOR were able to identify which flat was likely to be the worst performing in the block and to establish a ‘worst case’ baseline for the properties. From there, a retrofit assessment was carried out to support the theory. This enabled early information to be presented back to the client to aid strategic and commercial decision making.

46% reduction in co2 emissions
Trewyn Flats EPC Result


Gaining access to the properties and locked communal areas (loft spaces, basements) proved to be one of the biggest challenges and required VOR to ensure the residents were engaged and on board with the process. The site is also situated on a slope which meant the topography of the basements to the ground floor flats differed considerably. One of the flats was operating on a single-phase meter which led to anomalies on comparable units.  

Early measures recommended included improvements to the communal areas, internal wall and solid wall insulation and upgrading of windows & doors. Whilst these measures alone would improve energy performance they would not meet the Client’s funding requirements so further measures were recommended including improvements to the properties’ high retention storage heaters, To achieve net zero a further phase of external wall insulation, a MVHR system and underfloor insulation were proposed.  

Heat Demand
Energy Bills

Energy Efficiency Measures


Air Tightness of properties to be 3.0Ach/hour



Solid Wall Insulation on unheated corridor to 0.18 at Phase 1. EWI to 0.18 on entire envelope at phase 3. Floor to 0.15 at phase 3



All Intermittent extract ventilation to be replaced with decentralised mechanical extract fans. This is to be applied to all wet rooms. MVHR to be implemented at phase 3



Secondary heating to be removed and old retention storage heaters to be replaced with High Heat Retention Storage. Cylinder insulation to meet 1.3kWh/day


Southeast facing. It is calculated that there is space available for 2kW of solar PV per apartment at phase 2

What the Client said

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“VOR have been great to work with, helping us take forward individual retrofits, architype work and develop some of our large scale funded projects, they have bought quality technical knowledge about PAS 2035, undertaken detailed and rigorous assessments and have been key to supporting our planning to help us deliver high quality retrofit work across our stock.”

Tim Wotton, Green Funding Manager