Those generous Carshalton gardens deserve more than just lawn and borders. A thoughtfully designed annexe transforms unused space into something extraordinary – whether that's a teenage retreat, home office, or granny flat.
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Carshalton's leafy streets and substantial Victorian plots create perfect opportunities for garden annexes. Many SM5 properties sit on quarter-acre plots with side access wide enough for construction vehicles. The local planning department has become increasingly supportive of quality garden buildings, particularly when they enhance rather than dominate the existing landscape.
Building regulations compliance forms the backbone of any successful annexe project. Insulation standards exceed those of most main houses, ensuring year-round comfort without excessive heating bills. Foundations go deeper than you'd expect – typically 600mm minimum to handle our London clay. Modern timber frame construction allows rapid weatherproofing, meaning your garden won't resemble a building site for months on end.
Twenty years of navigating Sutton Council's planning maze gives us distinct advantages. Long-standing relationships with local structural engineers and building control officers smooth potential hurdles before they arise.




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Basic 4x3m annexes start around £18,000, while fully-fitted 6x4m buildings with bathroom facilities typically range £35,000-45,000. Bespoke designs or premium finishes push towards £60,000.
Absolutely – from the conservation areas near Carshalton Ponds to modern estates in Hackbridge, we've built annexes across SM5 and neighbouring Wallington.
Standard annexes take 6-8 weeks once foundations begin. Complex designs with bathrooms or kitchens typically need 10-12 weeks, weather permitting.
Structural timber frames carry decade-long protection, while EPDM rubber roofing includes manufacturer-backed 20-year warranties. All electrical and plumbing work meets current Part P regulations.
Generally no – annexes used by family members remain part of your main property for tax purposes. Independent rental units may trigger separate banding, so discuss intended use during planning stages.
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