I Built an Annex for My Daughter and Her Family in My Backyard

This as-told-to essay is based on a conversation with Sacha Warren from Surrey, England. Warren’s financials have been verified by Business Insider. It has been edited for length and clarity.

I bought my house in Epsom, a town outside London, in 2001. It has a huge garden, and I knew I’d never leave.

I was lucky to get on the property ladder. My dad gave me the deposit for a one-bedroom apartment in 1997. UK property prices surged around that time, so when I sold it, I got a healthy deposit for this house.

In 2005, a developer approached me about buying part of my land and putting two bungalows at the end of my garden. I loved the idea of being mortgage-free in my 20s, but they couldn’t get permission to build because of access issues.

Family at the bottom of the garden

A couple of years ago, my daughter started showing me videos of people building loft conversions or annexes. I didn’t have the money to even consider it.

Then, my daughter, who is now 22, and her boyfriend got pregnant. They were living with us and paying £350 a month in rent. We had the space, but it was important for them to be independent.

We started to think more seriously about the idea of building an annex. My daughter and I are close, and I liked the idea of all being together.

The cost of property in the area is ridiculous. Worrying about my daughter having a big mortgage kept me up at night.

I started researching annexes and found a local company. It would be a quick build and meant my daughter and her partner could get established as their own family unit.

They had an eight-month waiting list, but that gave me time to organize my finances.

Financing the project

I had paid off my mortgage in 2018 when the equity in my parents’ home was released, and they gave it to me as an early inheritance.

I took out a 20-year mortgage loan on my house last year to help cover the cost of the annex. I agreed with my daughter that they would cover this monthly payment.

The mortgage repayments are locked in for five years at 5.5%. They pay me £700 a month, or about $950, including utility bills. If they were paying rent on a two-bedroom apartment here, they could be paying twice that.

We never discussed a contract. In my will, my daughter is the sole beneficiary of my estate. We earn the same, and she completely understands the importance of earning money and paying bills.

If they want to move out, I’ll make the payments as the mortgage is in my name.

The 2-bedroom annex layout

We chose a prefabricated, two-bedroom annex with a bathroom, open plan kitchen, and lounge.

We could choose options for each room. I thought it was going to be stressful, but it was enjoyable. The company did everything for us. They even applied for permission to build it.

They needed to install water and electricity, but they were able to connect them to our mains supply. We installed a meter in case we rent the annex out in the future. The build took six weeks from start to finish.

The annex needs to be repainted every six years, and the sewage system costs £750 a year to maintain. My daughter and her boyfriend put money aside each month for when the bill comes through. 


Sharing the property is a slice of heaven

My daughter gave birth in January 2024, and they moved into the annex in September. We wanted them to be settled in it before the baby arrived, but it ended up being a really special time sharing our grandson’s early days in the house.

Now, we’ll send each other WhatsApps, and if I’m sitting on the patio, my daughter or her boyfriend might come out to chat or socialize. We don’t tiptoe around each other. They do their own food shopping, but if one of us makes too much food, we’ll share it.

I work as a dementia care assistant for the same company as my daughter, who is a manager there, and her partner is a plasterer. She and I are both contracted to work 28 hours a week, so we’ll mirror each other’s shifts. I can help with babysitting duties, but her boyfriend’s mother also helps.

I love where I live — I’ll never move. My daughter is my only child, so the house will be hers anyway. If she wanted to have more children, perhaps her dad and I could move into the annex.

This is our little slice of heaven.