PlandyUK Planning Platform

For Homeowners

Understand what your home could become before you spend on plans.

Plandy helps homeowners check likely planning outcomes, compare extension options, and evaluate planning permission requirements before spending money on plans or speaking to designers, builders, or estate agents.

Local policy signals Nearby precedents Project risk score
Illustrated home used to preview extension likelihoods
Selected project

Single-storey extension

Usually the cleanest route when depth, height, materials, and neighbour impact stay within policy limits.

92%Very strong

Red to green likelihood based on common householder planning constraints and local precedent signals.

Planning Feasibility

Assess planning feasibility before the expensive parts start

Check whether your project qualifies as a permitted development extension or requires a full householder planning application.

Avoid wasted design spend

Assess planning feasibility early and understand your likely approval route before commissioning drawings or submitting forms.

See local precedent

Review nearby approvals and refusals to check whether a permitted development extension or full application suits your site best.

Prepare stronger applications

Get a practical action list covering policy issues, property constraints, planning feasibility signals, and avoidable red flags.

What Can You Build

Compare common projects against planning risk

Explore options for a single-storey extension, rear extension, or side extension, from permitted development rules through to projects that need a full householder application.

Single-storey rear & side extensions

Check feasibility for a rear extension, side extension, or wraparound single-storey extension under local planning rules.

Loft conversions & roof alterations

Loft conversions, dormers, hip-to-gable changes, and roof space extensions.

Work and storage space

Garage conversions, garden offices, studios, workshops, and outbuildings.

Buying Or Selling

Turn planning potential into clearer property decisions

Whether you are asking what size extension can I build or looking to build an extension without planning permission, Plandy helps buyers test property potential before exchange and allows sellers to showcase credible extension opportunities.

BuyingDetermine what size extension can I build on a prospective home before making an offer.
SellingShow buyers what can be built, including options for an extension without planning permission.
RenovatingPrioritise projects by likely approval, cost of planning risk, and practical complexity.

FAQs

Planning permission & extension FAQs

Clear answers to common questions about planning permission, permitted development rules, and extension sizes.

Not always. Many single-storey rear extensions and side extensions fall under permitted development rights, provided they meet specific limits on depth, height, and boundary proximity. Full planning permission is required if your proposal exceeds these limits or is located in a conservation area.

Get Started

Check your home's extension potential

Find out whether your planned rear extension, side extension, or loft conversion is feasible under permitted development or requires full planning permission.