Swift bricks, bat boxes and conditioning integrated features

Integrated bird bat boxes planning conditions are among the easiest to satisfy and the most often botched. A condition requires bird and bat features, the drawings show a swift brick symbol somewhere on the east elevation, and two years later there is a nest brick at 2.4 metres above a kitchen window with a downlight pointing at it. Nothing is nesting in it and nothing ever will.

The difference between a feature that works and one that decorates a wall is specification, and that is entirely within an architect's control.

Why enhancement sits alongside mitigation

Mitigation replaces what the development takes. Enhancement adds something that was not there before, and the two are separate obligations that councils increasingly condition separately.

The duty comes from the biodiversity duty on public authorities, strengthened by the Environment Act 2021, together with national policy expecting development to provide net gains for biodiversity. Integrated features are the least costly and most durable way of delivering part of that on a building, which is why they appear in almost every local plan adopted in the last few years.

They are not a substitute for a protected species licence. Where a roost is lost, the compensation is whatever the licence requires, and a Protected Species Survey and the licensing process determine that. Enhancement features are additional to it.

Product types, positions and orientations that work

Integral units built into the wall outperform externally fixed boxes on every measure. They do not decay, they cannot be removed by a resident, they do not need maintenance, and their thermal performance is steadier because the mass of the wall buffers them.

For swifts, the positions that get occupied share four characteristics: a height of at least five metres above ground, a clear unobstructed drop and flight line in front of the entrance, a north or east aspect or another position shaded from afternoon sun, and no window, door, balcony or bin store directly below. Swifts are colonial, so cluster several bricks on the same elevation rather than distributing one per house across a street.

For bats, the useful positions differ. Warm aspects facing between south and west suit maternity use, heights above four metres are preferred, the entrance needs a clear drop of a couple of metres because bats fall to fly, and the feature should sit away from the main entrance and from any area lit at night.

A general rule that saves arguments later: keep both types away from gutters, soil pipes, utility boxes and anywhere a scaffold tie or a future solar array will sit. The British Standard on integral nest boxes sets out selection and installation requirements and is worth specifying by reference rather than describing in your own words.

Lighting and the flight line

Lighting undoes more integrated features than bad positioning does. A bat tube on a warm gable is useless if an amenity light washes the elevation from dusk, because bats will not emerge into illumination.

Coordinate the external lighting layout with the feature positions at the same design stage rather than in separate packages. Keep luminaires off the elevations carrying features, use warmer colour temperatures and tighter optics where light near them is unavoidable, and avoid uplighting entirely. Where a lighting assessment is being prepared for other reasons, include the feature positions on its drawings so the two are checked together.

Landscape planting is the slower version of the same problem. A tree that reaches the elevation in fifteen years blocks the flight line to a nest brick that was working perfectly, so mark the features on the planting plan.

Numbers, and where the expectation comes from

Many councils now ask for a stated number of features per dwelling, commonly expressed as at least one integrated nest brick per home, sometimes with a separate bat feature requirement on larger schemes. Others set a proportion of dwellings or a figure per hectare.

The requirement is local rather than national, so take it from the adopted local plan policy, the supplementary planning document or the council's validation checklist, and cite the source in the submission. Proposals for a national requirement have been debated, but check the current position before describing anything as a statutory duty.

Where no local figure exists, propose one and justify it. A scheme that offers a considered number with reasoning behind it is in a better position than one that waits for the council to impose a figure at condition stage.

Specifying so the condition can be discharged

The discharge is straightforward when the application drawings already contain everything the condition will ask for.

1. A schedule listing each feature type, the manufacturer's product reference or an equivalent performance specification, and the quantity of each.
2. Elevation drawings showing every feature in position, with the height above finished ground level dimensioned.
3. The orientation of each elevation marked, so the aspect can be checked without a site plan.
4. A typical installation detail showing how the unit sits within the wall construction, including any insulation, cavity closer or render finish.
5. A note stating that entrances must not be obstructed by render, insulation, mesh or paint.

That last point sounds trivial and is responsible for a large share of failed features. Nest bricks get rendered over, entrances get filled with expanding foam by a well-meaning contractor, and mesh intended to keep birds out of the scaffold is left in place.

Ask for the condition to refer to those drawings rather than requiring a further scheme. A condition worded as development in accordance with the approved drawing numbers is discharged by building it.

What the biodiversity metric does and does not count

Be clear about this, because councils and applicants both get it wrong. The statutory biodiversity metric measures habitat area, type and condition. Nest bricks and bat tubes are not habitat in the metric's terms and generate no biodiversity units.

So integrated features cannot contribute to the ten per cent gain requirement, and a biodiversity net gain assessment that counts them is wrong and will be corrected on review. They are a separate enhancement, valuable in their own right and required by different policy.

Say so in the ecology documents rather than leaving the two sets of numbers to be reconciled by a reviewer. A Preliminary Ecological Appraisal that lists the enhancement features in their own section, distinct from the metric outputs and from any licensed mitigation, keeps the three strands apart.

Recording installation

The discharge evidence is photographic. Dated photographs of each feature in position with a recognisable elevation reference, taken before scaffold strike while access is available, plus an as-built drawing marking the location of each one.

Take them at the right moment. Once the scaffold is down, photographing a nest brick at six metres needs a long lens and good light, and the site manager has moved on.

Handing the resident an information sheet costs nothing and prevents a fair amount of harm. People paint over entrances, fit alarm boxes next to them and drill through them for satellite brackets, usually because nobody told them the brick was anything other than a brick.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. Where protected species are present, survey and licensing work must be carried out by a suitably licensed ecologist. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.

Enter your postcode on PlanScope to see which ecology reports a housing scheme is likely to need.