Mark is 44, a plumber in Croydon, has two kids in primary school, and pays £1,840 a month on a 25-year mortgage he took out in 2020. Last weekend, sitting at his kitchen table, he showed me the spreadsheet he keeps in a notebook.
Three Packhood listings. £180, £165, £215 a month. Total gross: £6,720 a year. After the platform fee and basic-rate tax (with £1,000 trading allowance applied), ~£4,400 net. That's £367 a month — a bit less than half his mortgage payment, paid by stuff he's not using. He listed all three over a weekend in May 2024.
He's not a special case. He's just a guy who realised before everyone else in his estate that the house he bought in 2017 had three storage-able rooms in it earning him zero. Here's exactly what he did.
Listing 1: his own garage in Croydon (£180/mo)
Started with what was easiest. Single-car garage attached to his end-of-terrace, around the back. Used to hold a workbench he hadn't touched in three years, a chest freezer, and four boxes of his late mum's tools he was "going to sort one day." Cleared the floor on the Saturday morning, took five photos, listed at lunchtime.
First booking: 9 days. A young couple between rentals near East Croydon. They've been in for 21 months and counting; their booking has rolled twice. Combined Mark's earned £3,780 from this one listing.
His comment when I asked what surprised him: "The couple — I don't think I've spoken to them in 14 months. They pay every month, they're tidy, they don't bother me. I'd half forgotten they were renters."
Listing 2: his parents' empty garage in Beckenham (£165/mo)
Mark's parents moved into a sheltered flat in 2022. Their original 1960s semi in Beckenham has been empty since. The garage at the back was full of his father's tools and his mother's National Geographic magazines from 1989.
Saturday afternoon, with listing 1 done, he drove over to Beckenham, cleared the garage in two hours (binned 80% of the contents — "if I haven't used Dad's pipe wrenches in three years I'm not going to"), photographed it, listed it.
First booking: 14 days. A returning emigrant from Singapore shipping back furniture from a 5-year stint. Stayed 12 months. Replaced 3 weeks later by a small-business owner storing inventory. Combined: £2,640 across 17 months.
The lever: Mark's parents weren't paying for the garage to earn money — but they were paying council tax, building insurance, and gas standing charges on the empty house. The £165/mo from this listing now covers all those costs and contributes toward the parents' lunches.
Listing 3: a new shed in his back garden (£215/mo)
Sunday, after he saw listing 1 already had two inquiry messages, Mark drove to B&Q. Bought a 3m × 2.5m metal shed for £840 with anti-corrosion treatment + reinforced lockable doors + alarm sensor. Spent 2 hours assembling it on a corner of his back garden the same afternoon. Listed it as "Outdoor-covered storage in Croydon, alarmed, ground-level, 24/7 access" — the highest-rate-per-cubic-metre listing in his postcode.
First booking: 16 days. A wedding photographer storing equipment between weddings. Has been in 13 months at the same rate. Earned to date: £2,795.
Payback math: Shed cost £840. After 4 months of rent the shed had paid itself off. Months 5+ are pure cashflow on a depreciating asset he doesn't use. The shed will earn ~£2,580/yr for the next 12+ years with effectively zero maintenance.
Mark's portfolio summary (24 months in)
Listing 1 (his garage): £3,780 across 21 months. Renter-1 still in.
Listing 2 (parents' garage): £2,640 across 17 months. Two renters back-to-back.
Listing 3 (purpose-built shed): £2,795 across 13 months. One renter, going strong.
Total gross 24 months: £9,215. Net after platform fee + basic-rate tax (with £1,000 allowance applied to gross): ~£6,000. Effective monthly average: £250.
Total time invested: approximately 16 hours (initial weekend listing setup, three move-ins, eight chat messages, two renewals).
Why most south-London plumbers haven't done this
When Mark tells people about it at the pub, the response is some version of: "Yeah, I've heard of that, I'd do it, just busy with stuff." A year later, same conversation, same answer.
Mark's actual differentiator wasn't expertise, capital, or special access. It was that he opened the listing form on a Saturday morning and didn't let himself walk away until the photos were uploaded. Everyone else has the listing in their head as "something to look into." It never gets done.
Six other plumbers Mark knows have garages they could list. None of them have. He'll have collected approximately £18,000-£22,000 by the time any of them get round to it.
Run the math on your own house
Walk through your home and any second property your family has access to. Count every storable space — garages, sheds, attics with hatches, basements, large unused rooms, dedicated outhouses. For each one estimate £70-£200/mo at city median (London is the higher end). Add them up.
If your number is over £3,500/yr of theoretical gross: the question isn't whether to list, it's how soon. Open the listing form right now. Don't tell yourself "this weekend." The Marks of Croydon are the ones who clicked through within ten minutes of reading something like this.