Evidence you can build on.
We survey it, model it, and tell you what the site will allow before anyone draws a layout on it.
How the practice is built
Field
Twenty-six people who spend most of their week outdoors. Six licensed ecological surveyors, Class 1 acoustic instruments, our own diffusion tube network, and a drilling rig we do not have to book three weeks ahead.
Model
ADMS and AERMOD for dispersion, HEC-RAS and Flood Modeller for hydraulics, the statutory biodiversity metric, and verification against measured data rather than against a default.
Consent
Fourteen environmental statements coordinated, nine negative screening opinions obtained, and thirty-one of thirty-four verification reports accepted by the local authority first time.
Our position
Environmental work is worth something only while the design can still change.
Most of the environmental reporting produced in this country is a compliance exercise carried out after the decisions have been made. It is competent, it is expensive, and it changes nothing, because by the time it lands the layout is costed and the option is exercised.
We would rather be in the room in month one. That is where a relocated attenuation basin turns a 6.1% biodiversity shortfall into a 12.4% surplus, where a ballasted mounting system removes an Environment Agency objection across 22 hectares, and where a tested infiltration rate stops a drainage strategy being designed on a hope.
It also means occasionally telling a client that the site does not work. We did that twice in 2025. One of those clients has not instructed us since. That is the price of the advice being worth taking.
Services
Six disciplines, one office, one project manager
Ecology & biodiversity
Preliminary appraisals, protected species surveys and statutory biodiversity net gain, with the metric run before the layout is fixed rather than after.
Read moreAir quality & odour
Construction dust assessments, road traffic and combustion dispersion modelling, and odour assessment for waste and wastewater.
Read moreAcoustics & vibration
BS 4142 industrial noise, BS 8233 internal levels, construction noise to BS 5228, and vibration to BS 6472 with the measurements to back it.
Read moreLand & groundwater
Phase 1 desk studies, intrusive investigation, remediation strategies and verification, plus hydrogeological risk assessment for the Environment Agency.
Read moreWater & flood risk
Flood risk assessments, hydraulic modelling, SuDS design to the national standards, and water framework directive compliance.
Read morePlanning & EIA
EIA screening and scoping, environmental statement coordination, and the pre-application work that decides how difficult the rest will be.
Read more
Working at Thornfield
Fifty-four people who have mostly chosen not to leave
One office, no regional structure, and an average tenure of 9.2 years in a sector where three is normal. We are not going to pretend that is entirely a matter of culture — Reading is an expensive place to live and we pay above the CIEEM salary guidance because we have to.
- 2011
- Founded in Reading
- 54
- Staff, one office
- 14
- Environmental statements coordinated
- 9.2
- Years, average tenure
Recent projects
Housing
Marlow Reach
A 212-unit scheme that reached 12.4% biodiversity net gain on site by moving a drainage basin at concept stage, and kept an oak that the first layout had removed.
Read more
Energy
Ridgeway Solar
18 MW on a capped 1970s landfill. The gas risk assessment was the whole job; the ecology and glint work took three weeks.
Read more
Water
Kennet storm overflow
Permit variation and WFD assessment for a 14,000 m³ storm tank, delivered against an AMP deadline with four weeks of contingency and no extension of time.
Read moreGet in touch
Tell us about the site before you buy it
A twenty-minute call at option stage is the cheapest environmental advice you will ever take, and occasionally it is the advice not to proceed.