Play space assessment: child yield and the calculation

A play space assessment calculation starts with arithmetic. You estimate how many children the scheme will house, multiply that figure by the provision standard in the adopted local plan, then show where the resulting square metres sit, how they divide by age group and who maintains them. Get the child yield wrong and everything downstream is wrong with it, including the commuted sum an officer asks for when on-site provision falls short.

Most councils want this work once a scheme passes the major threshold of 10 dwellings. Smaller schemes can still trigger it where local policy sets a lower bar, or where the site adjoins an existing play area that the new households will use. A Play Space Assessment is rarely long. It is one of the few supporting documents an officer will check line by line, because the maths is reproducible and either it adds up or it does not.

Estimating child yield from the unit mix

Child yield is the number of children a development is expected to accommodate, derived from the schedule of units rather than from a headline population figure. Two inputs drive it: the number of bedrooms in each unit, and the tenure. A three-bedroom affordable rented home is expected to house more children than a three-bedroom market flat, and the multipliers councils publish reflect that difference.

In London, the Greater London Authority publishes a population yield calculator that converts a schedule of units by size and tenure into expected numbers of children in defined age bands. Outside London the multipliers usually sit in a local plan policy, a planning obligations supplementary planning document, or the open space evidence base that sat behind the plan. Ask the case officer which set applies before you model anything. Two authorities either side of a district boundary can produce noticeably different yields for an identical schedule, and the difference is policy, not error.

Set the calculation out as a table the officer can rebuild without ringing you. The illustrative example below uses placeholder multipliers rather than any published standard, to show the shape of the working:

Round the total once, at the end, and say so. Rounding each row up produces a number that looks careless when the officer repeats the sum. Where the mix is still moving, run the calculation on the worst case for yield and note the sensitivity, because a late switch of two market flats to affordable rent can push provision over a threshold.

Tenure is the input most likely to change between validation and committee, which is why the play figures should be cross-referenced to the Affordable Housing Statement rather than restated independently. Two documents giving two unit mixes is a validation query waiting to happen.

Provision standards and how the square metres are derived

Once you have a child figure, the standard converts it into an area. London Plan 2021 Policy S4 sets 10 m² of good quality playable space per child for major residential development, and that is the number most commonly quoted in the capital. Elsewhere the standard may be expressed per child, per dwelling or per 1,000 population, and many authorities built their figures on the Fields in Trust benchmarks for equipped playing space.

Three errors recur in submitted assessments:

1. Mixing standards. A per-1,000-population benchmark and a per-child standard cannot be averaged together, and applying both to the same scheme double counts.
2. Counting the same ground twice. A square metre of communal garden cannot serve as both private amenity space for a ground-floor flat and playable space for the block.
3. Treating playable space as equipment. Policy asks for space children can play in, which includes informal lawn, planting, level changes and hard surfaces that take a ball.

Where the on-site figure falls short, the shortfall converts into a financial contribution under a section 106 obligation, usually towards improving a named facility within a stated distance. Say which facility, and check that the council's own evidence base identifies it as deficient. A contribution towards nothing in particular fails the tests in the Community Infrastructure Levy Regulations 2010.

Age groups and what each tier needs

Provision is split by age because a single fenced area with a spring rocker serves one band and ignores the rest. The usual division is under-5s, 5 to 11, and 12 and over.

Under-5s need space within sight and earshot of a front door, with a surface that takes a pushchair and something to sit on for the adult who is watching. The 5 to 11 band needs equipment, something to climb and enough run-around area for a game. The 12-plus band is the one schemes forget, and it is the band that generates complaints when it is left out: teenagers occupy whatever space exists, which is normally a bin store or the space outside somebody's window. A kickabout area, a sheltered seating group or a ball court answers it properly.

Present the split as a share of the total area, then as a location on a plan. Officers check that the 12-plus provision has not quietly been absorbed into the under-5 doorstep area.

Doorstep, local and neighbourhood provision

The tiers are about walking distance from the front door, and they map onto the age bands. The Mayor's play and informal recreation guidance works to roughly 100 metres for doorstep playable space, 400 metres for local provision and 800 metres for neighbourhood provision, and many authorities outside London use comparable distances drawn from the same sources.

Existing off-site provision can count towards the requirement where it is within the relevant distance, reachable on foot and has capacity. Three conditions, all of which have to be evidenced. Reachable means a route a seven-year-old can take, so a play area 300 metres away across a distributor road with no crossing is not 300 metres away in any meaningful sense. Walk the route and photograph it. Capacity means the existing facility is not already recorded as over-used in the council's open space study, which is the same document behind an Open Space Assessment.

Fields in Trust guidance also sets a buffer between play equipment and the nearest dwelling. That buffer is what stops a locally equipped area being squeezed against a ground-floor bedroom window late in the design process, so fix the buffer on the layout before the unit count is finalised. Check the current edition of the guidance for the figure that applies.

Where communal amenity space and play space overlap

Most policies allow playable space to sit within communal amenity space provided it is designed for play, and treat it as additional to private balconies and gardens. The practical test an officer applies is whether a child could actually play there. A strip of shrub bed between a car park and a boundary fence meets no standard, whatever its area.

Courtyards carry the same design constraints the team is already testing elsewhere. Overshadowing from the surrounding blocks decides whether the space is usable in March, and summer surface temperatures on dark hard landscaping sit in the same microclimate question as overheating under TM59. Run the sunlight study over the play area, not only over the dwellings, and show two hours of sun on part of the space at the equinox if you can achieve it.

Podium decks add a further constraint. Soil depth governs what can be planted, drainage falls govern where water stands after rain, and both are fixed by the structure long before the landscape drawings are issued.

Design quality, inclusion and equipment standards

Equipment supplied for public use is designed and installed to BS EN 1176, with impact-absorbing surfacing to BS EN 1177. Naming the standards in the assessment, and requiring them in the landscape specification, is the straightforward part. The harder part is inclusion.

Inclusive play means a disabled child can reach the space, get onto or into something, and play alongside other children rather than beside them. A wheelchair-accessible route to the gate and one ground-level item is the minimum that reads as a real attempt. The Equality Act 2010 public sector equality duty applies to the council's decision, so a scheme that ignores inclusion gives an objector an easy point and gives the officer a reason to ask for more.

Natural play features earn their place here. Logs, boulders, mounds and planting cost less to maintain than manufactured equipment, last longer and answer a wider age range. They also survive the value engineering exercise better, which matters more than it should.

Maintenance, inspection and the commuted sum

Every play area needs an owner. The three routes are adoption by the council with a commuted sum for future maintenance, transfer to a management company funded through an estate service charge, or retention by a registered provider where the space sits within its holding. Say which one applies, and say it in the same terms the draft section 106 heads of terms use.

Inspection follows the equipment standard: BS EN 1176-7 covers installation, inspection, operation and maintenance, and a routine visual, operational and annual main inspection regime is what a council's parks team will expect to see committed to. Where a commuted sum is offered, the council will usually calculate it from its own published maintenance rates over a set period, so ask for the rate and the period early. That figure feeds straight into the appraisal, and a late commuted sum is a familiar reason a scheme returns to the Viability Assessment after the design is fixed.

One honest uncertainty: play standards are among the most locally variable requirements in English planning, and the same scheme can face very different required areas on either side of a district boundary. That is why the pre-application question about which standard applies is worth more than any amount of careful modelling against the wrong figure.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope can draft the assessment structure and the calculation table for you once the unit schedule and the local standard are in: enter your postcode to see which reports your site needs.

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