Join the urban space men building offices and annexes in their back gardens

Some are building offices to work from home, while others are adding "granny" annexes for elderly or disabled relatives. More ambitious "self-builders" want to raise income by attracting holiday lets or renting out space to long-term tenants. One in three would take on a major project even if it would shrink their garden space, says specialist mortgage lender Together. Distribution development manager Scott Clay said the first step is to put the right finance in place, by remortgaging, applying for a specialist self-build mortgage or taking out a bridging loan.

Happiness begins at home for Tim Lamont, who fulfilled his dream of building a cottage from scratch by using his own garden as the plot.

Yet he almost fell at the first hurdle when his existing mortgage lender refused to help. He turned to Together, which remortgaged his East Grinstead home to raise £177,000 last year.

After getting planning permission,

Tim split the land to create a separate title and teamed up with a local builder, while his wife Janet oversaw the finances and interior design.

Observing social distancing on a congested plot and obtaining materials were the biggest challenges, he said: "Planning is everything and keeping neighbours informed is essential."

Tim and Janet, who have three children, are living in Jasmine Cottage but may rent it out to boost their income in retirement. They now have further dreams, he said: "We'd like to add to our self-build portfolio by building our dream eco-home."

Duncan Hayes, National Custom and Self-BuildAssociation spokesman, said planning authorities have different approaches to building on garden plots: "Many want to prevent inappropriate or damaging garden development, so check your local council's policy on its website."

Andrew Baggott, managing partner and chartered accountant at Clarke Nicklin, said there are tax advantages as self-builders can recover the VAT on most labour and material costs: "Submit a claim to HMRC within three months of completion."

He added there is usually no stamp duty to pay but capital gains tax could be an issue: "Your primary home is exempt but if you build an entirely new one and have two properties, one may become taxable, so take advice."

Shed sales have risen fivefold as homeworkers convert them into a home office, or "shoffice", according to supplier Toolstation. Head of marketing Greg Richardson said: "They may also add value when you sell, as more people work at home and are looking for office space."

Johnpaul Manning, MD at building supplier Insulation4Less, said if buying or converting a shed for home office use, consider larger windows or even a skylight for more natural light.

Also install insulation, weather strips around windows and a door bottom draft blocker. "This will help keep your shed or summerhouse warm and in good condition," he said.