A site owner in Cumbria emailed me last spring about two couples' pods she'd bought for the 2024 season. Larch cladding, king-size bed, wood burner, hot tub on the deck. By January 2026 she had a soft spot in the floor beside the tub and a smell in the wardrobe she couldn't trace. Her question was simple: is this a bad manufacturer?
It wasn't. That's the frustrating part. The pods were built to the standard they were sold under. She was just using them in a way nobody had written down.
I'm a quality and brand compliance manager at a modular accommodation manufacturer. I sign off every unit before it leaves the yard — roughly 150 a year, glamping pods, transportable cabins, small residential units, occasional 3-bedroom transportable homes. In 2024 I rejected 19% of first-article builds before we went to full production. Most of those rejections weren't anyone's fault in any obvious sense.
Here's what I mean.
The Problem You Think You Have
If you've ever compared pod brochures, you know they all promise the same seven things. Fully insulated. Scandinavian timber. Turnkey. Built to last. Hot tub ready.
That last one is doing an enormous amount of unexamined work.
So the buying decision turns into a comparison exercise: 12-year structural warranty versus 10, £38k versus £52k, four weeks versus nine. Which is the wrong frame entirely, because the pods that fail are rarely the ones that looked weakest on the spreadsheet.
The problem isn't product quality. It's a mismatch between the standard the unit was built to and the job you're asking it to do.
What's Actually Going Wrong
It's built to a leisure standard, not a housing standard
This is the one nobody explains at the point of sale.
BS EN 1647 is the standard for caravan holiday homes — the habitation requirements relating to health and safety. BS 3632:2015 is the standard for residential park homes, designed for year-round occupation. Different thermal requirements, different ventilation assumptions, different condensation expectations.
Neither standard is bad. But if you buy a unit certified to the holiday-home standard and then let it 200 nights a year, starting in February, to couples running a 38°C hot tub with the door open to the deck, you've taken a structure designed for seasonal leisure use and dropped it into one of the wettest inhabited places in England. Nobody broke a rule. You bought the wrong standard for your use case.
To be fair, plenty of manufacturers are upfront about this — the good ones will tell you which regime you're in before you ask. The ones who list 'fully insulated' without saying insulated to what are the ones to watch.
And it isn't a caravan — which changes everything downstream
This catches people buying 3-bedroom transportable homes and portable buildings marketed alongside pods.
Under the Caravan Sites Act 1968, a caravan is capped at 20 feet long excluding the drawbar, 6 ft 8 in wide, and 10 ft high internally. A three-bedroom transportable home is almost never inside those numbers.
Which means it isn't a caravan. It's a building. Building Regulations apply. Planning permission almost certainly applies. The insurance is a different product entirely. And the site licence covering your glamping units may not cover it at all.
I watched a site owner find this out at the point of an insurance claim. That is a very bad day, and it is entirely avoidable.
Nobody engineered the hot tub
This is the failure that costs the most and gets discussed the least, and it's specific to the 'glamping for couples with hot tub' model.
A domestic floor is typically designed for around 1.5–2.0 kN/m² under BS EN 1991-1-1. Call it 150–200 kg per square metre. A six-seat hot tub, filled, runs 2,000–2,500 kg. Sit that on a 2.2 m × 2.2 m footprint and you're at roughly 400–500 kg/m². Two and a half times the design load, before four adults get in, and before you account for the fact that the weight lands on four feet rather than spreading.
Now the trap. The deck is usually built by the site, after delivery, by a local joiner. So it sits outside the pod manufacturer's warranty and outside their scope. Both parties are technically correct. Neither has done the calculation.
I went back and forth on this for about a month at our place — make structural load calcs part of the standard spec, or keep them as an optional line item. Standard added roughly £340 per unit. Optional meant about half our customers skipped it. We made it standard. It was the right call, but it took two warranty disputes to get there.
The water has nowhere to go
Timber frames go together at 16–20% moisture content. That's normal and fine. What isn't normal is the environment a hot tub creates: a large body of warm water, in a small sealed volume, in a climate that sits above 80% relative humidity for much of the year. Run that through a season and you're driving vapour into the structure continuously.
If the vapour control layer ends up on the cold side, or the sub-floor is sealed with no drainage path, that vapour condenses inside the build-up. You won't see it for 18 months. You'll smell it first.
There's a second, much dumber path: splash and overflow. Chemically treated water running off a deck and sitting against the bottom rail. That's where the soft spot in the floorboard comes from more often than people expect (ugh).
What It Costs When It Goes Wrong
Real numbers from two failures I've been asked to look at over the past three years:
- Rebuilding the floor and re-cladding a single 24 m² pod: £11,000–£19,000, plus 6–10 weeks out of service.
- Lost booking revenue across that window. At £240–£320 a night for a couples' pod in the Lakes, a six-week gap through August and September lands somewhere around £10,000–£13,000. Don't hold me to that figure — it depends entirely on your occupancy, and peak-season Lakes pricing moves.
- One denied insurance claim, because the hot tub and its deck were never declared as modifications to the unit.
- One planning enforcement enquiry, because the 'transportable home' sat outside the caravan definition on a site licensed for caravans.
The surprise, in both cases I know best, wasn't that the budget units had problems. It was that the £52,000 ones did too — because the extra money had gone into cladding, interiors and the website photography rather than the floor build-up and the sub-floor detailing. You can't photograph a vapour control layer, so nobody sells on it.
What I'd Check Instead
Four things. None of them require a technical background.
- Ask what standard, in writing. 'Which standard is this unit certified to, and does that certification cover year-round, high-occupancy use?' If the answer comes back as a brochure PDF, that's your answer.
- Get the hot tub load into the drawing package. Ask for a structural calculation for the deck and the floor, from a named engineer, with the specific tub model and its filled weight in it. Not 'hot tub ready'. The number.
- Inspect in the factory, before it ships. Moisture meter on the frame, eyes on the sub-floor vapour control layer, and a look at the drainage and ventilation paths. You cannot see any of this in a showroom, and it's the only 40 minutes that actually matters.
- Check your own regime first. Under 20 ft, 6 ft 8 in, 10 ft internally? If not, you're not buying a caravan, and everything downstream changes.
Where I'd Step Aside
I'm not the right person to design your deck. I'm not the right person to wire your hot tub. I'll tell you what I think of the pod, tell you what I'd want to see underneath it, hand you the number of a structural engineer and a Part P registered electrician, and get out of the way.
I'd rather work with a supplier who knows their limits than one who says yes to everything. The manufacturer who once told me 'deck's not our strength, here's who does it better' is the reason I used them for everything else afterwards.
That's the whole point. The pod maker who says 'we build pods, not decks' is telling you they understand where their warranty stops. The one who says 'we do it all' is telling you where the gaps are going to appear — you just won't find out for 19 months.
One caveat: this was accurate as of spring 2026. The standards get amended, UKCA marking rules keep shifting, and the legal definition of a caravan has been under review for years. Verify the current position before you sign anything.
Looking back at that site owner's two pods, I should have asked her one question at the start: show me the load calculation for the deck. She'd have found the problem in month one instead of month nineteen.
