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Extension Costs

This is usually the first question our customers ask. To help answer it, we've created a simple and cutting-edge costing tool. Extension costs in London can vary, and our cost calculator will hopefully provide some much-needed clarity.

Our tool makes it easy for you to see exactly what extensions are available to you, and at what cost. We've also provided 3D models of how your extension would look, helping you bring your new vision for your home to life. Once you've settled on your chosen extension, simply contact Plus Rooms today and we'll do the rest!

House type

Select from below options
Detached
Detached
Semi-detached
Semi-detached
End of terrace
End of terrace
Terraced - Flat Back
Terraced - Flat Back
Terraced - L Shaped
Terraced - L Shaped
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All example costs:

All estimated costs include building work, plumbing, electricity, glazing, external doors and applicable VAT

Flat Roof
Medium Smaller Rear Extension
Estimated Cost:
£70,000
Flat Roof
Medium Rear Extension
Estimated Cost:
£125,000
Crown Roof
Medium Rear Extension
Estimated Cost:
£95,000
Flat Roof
Large Wraparound Extension
Estimated Cost:
£190,000
Crown Roof
Large Wraparound Extension
Estimated Cost:
£170,000
Gable Roof
Large Wraparound Extension
Estimated Cost:
£108,000
Flat Roof
Large Wraparound Extension
Estimated Cost:
£112,000
Pitched (Hip) Roof
Large Wraparound Extension
Estimated Cost:
£95,000
Gable Roof
Medium Wraparound Extension
Estimated Cost:
£90,000
Flat Roof
Medium Wraparound Extension
Estimated Cost:
£93,000
Pitched (Hip) Roof
Medium Wraparound Extension
Estimated Cost:
£85,000
Gable Roof
Small Wraparound Extension
Estimated Cost:
£80,000
Flat Roof
Small Wraparound Extension
Estimated Cost:
£80,000
Pitched (Hip) Roof
Small Wraparound Extension
Estimated Cost:
£75,000
Pitched & Flat Roof
Large Side & Rear Extension
Estimated Cost:
£100,000
Pitched & Flat Roof
Medium Side & Rear Extension
Estimated Cost:
£85,000
Pitched & Flat Roof
Small Side & Rear Extension
Estimated Cost:
£78,000
Flat Roof
Large Side Return
Estimated Cost:
£80,000
Pitched Roof
Large Side Return
Estimated Cost:
£80,000
Flat Roof
Medium Side Return
Estimated Cost:
£68,000
Pitched Roof
Medium Side Extension
Estimated Cost:
£68,000
Flat Roof
Small Side Return
Estimated Cost:
£60,000
Pitched Roof
Small Side Return
Estimated Cost:
£60,000
Flat Roof
3m x 3m Rear Extension
Estimated Cost:
£60,000
Pitched Roof
3m Rear Extension
Estimated Cost:
£80,000
Gable Roof
3m Rear Extension
Estimated Cost:
£83,000
Flat Roof
3m Rear Extension
Estimated Cost:
£82,000
Crown Roof
3m Rear Extension
Estimated Cost:
£70,000

Plus Rooms offers a comprehensive service, designed to simplify the process of planning and constructing your extension. We can even set up temporary kitchen facilities allowing homeowners to remain living in the house throughout the build. We cover many of the London boroughs and some of the home counties, please scroll down to see some examples of the type of work we do.

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