BNG units for housebuilders, from a fraction of a unit to full phases
Volume and SME housebuilders in England need off-site units that fit the metric, the programme and the budget. BNG Sourced by Green Acres BNG sources them from providers across England, free for developers.
- One requirement, one point of contact, supply from across England
- Every option checked against your metric, the trading rules and the spatial risk multiplier
- Whole and fractional units of all three types, with planning-ready documentation
- Free for developers: where our involvement results in an introduction, the provider pays us an introduction fee
Start the free sourcing check
About 30 seconds. We save your details at step one.
Free for developers. Your details are only used to source your units.
Small sites and fractional units
Most housing schemes of 9 or fewer dwellings need less than one unit. Since 6 August 2026, for minor development off-site gains sit on an equal footing with on-site gains, so you no longer need to exhaust on-site options first. We source fractional units of area habitat, hedgerow and watercourse and sites of 0.2 hectares or less may be exempt altogether where no priority habitat is affected.
Phased and volume schemes
Larger sites usually deliver some gain on site and buy the balance. The balance can be large and supply of the right distinctiveness local to the site is not guaranteed. We search early, show the multiplier arithmetic for local, adjacent and elsewhere options and can arrange forward allocation so units are reserved before permission is granted.
What we check for you
- The trading rules: like for like or better for high and very high distinctiveness habitat
- The spatial risk multiplier for every option
- Register status and the Section 106 or conservation covenant behind each site
- Allocation terms and documentation for your biodiversity gain plan
Planning condition to discharge?
Tell us your requirement and we'll start sourcing today.
A worked example: 14 homes on former pasture
A regional housebuilder has permission for 14 homes on 0.9 hectares of improved grassland in a shire district. The ecologist’s metric records a baseline of 3.6 area habitat units and 0.4 hedgerow units along one boundary that will be removed for the access. Post-development, gardens, a small open space and new planting deliver 1.9 area habitat units on site and no hedgerow. With the 10% uplift the scheme needs 3.96 area units and 0.44 hedgerow units, so the off-site deficit is 2.06 area units and 0.44 hedgerow units.
Because it is major development (10 or more dwellings), the biodiversity gain hierarchy applies and the gain plan must explain why more cannot be delivered on site. The developer tells us the two figures. We find a registered gain site in the same National Character Area offering medium distinctiveness grassland units (local, 1.0), so 2.06 units are allocated. Hedgerow supply is thinner; the nearest is in an adjacent authority, so 0.44 divided by 0.75 means buying 0.59 hedgerow units. Both allocations are recorded on the register and evidenced in the gain plan, which the authority approves within its eight-week window.
What to send us
- The metric or the planning condition if that is all you have
- The site postcode and planning reference
- Your decision date or the deadline for discharging the condition
- Whether phases will need further units later, so we can discuss forward allocation
Timings you can plan around
| Stage | Typical time |
|---|---|
| First response from a specialist | Within one working day |
| Matched options for medium distinctiveness area units | Days |
| Matched options for hedgerow, watercourse or high distinctiveness units | One to several weeks, depending on region |
| Allocation on the register once terms are agreed | Depends on the provider; usually days to a few weeks |
| Gain plan approval | Up to eight weeks from submission |
Housebuilder questions
Can I buy 0.3 of a unit?
Yes. Fractional units are common for minor development and we source them in all three unit types.
Does the equal footing rule apply to my site?
It applies to minor development only, which includes residential schemes of 9 or fewer dwellings on a site of 1 hectare or less. Major development still follows the biodiversity gain hierarchy.
Can units be reserved for a later phase?
Often, through a forward allocation or option agreement with the provider. We flag which providers offer this when we present options.
Is the self-build exemption still available?
No. The self-build and custom build exemption was removed on 6 August 2026.
What if my site is under 0.2 hectares?
It is exempt from 6 August 2026 as long as no on-site priority habitat is negatively affected. Use the exemption checker to confirm.
Can I use units from a site I own elsewhere?
Yes, if that land is registered as a gain site and secured for 30 years. Many housebuilders find it simpler to buy from an existing provider.
How does a BNG condition affect my start on site?
Development cannot begin until the biodiversity gain plan is approved, so allocate units before you submit the plan.
Related: how it works, BNG unit prices, exemption checker, all guides.
Ready to source units?
Tell us what the metric needs and we will do the rest.
- One requirement, one point of contact, supply from across England
- Options checked against your metric, the trading rules and the spatial risk multiplier
- Free for developers: where our involvement results in an introduction, the provider pays us an introduction fee
- A specialist in touch, typically within one working day
Free for developers. Your details are only used to source your units.