The patio base your hot tub actually needs
A filled six-person hot tub weighs about as much as a small van. Most patio bases are built for garden chairs. Here's what yours needs underneath it, and what that honestly costs.
3 m × 3 m · 9 m²
How big is it?
What's it made of?
What's there now?
Under your patio
- Slabs · 20mm
- Full mortar bed · 30mm
- Compacted MOT Type 1 sub-base · 100mm
- Lawn and topsoil dug out · 150mm
Where in the country?
Materials only
£640–780
Typical installed total
£1,400–1,950
That gap is labour, prep, waste and access — the slabs are the cheap part. It's the part quotes keep vague, and it's most of what you'll pay.
Prices checked August 2026 · Placeholder prices — real data landing soon.
That's the estimate. Now plan the patio you actually want.
With the pro pack — your patio, not a demo
Your real shape
Grow yours into an L, notch it round the shed, price the garden you've actually got — the wing below is costed from your own numbers.
Money back if it doesn't pay for itself.
The short version
A hot tub base is a patio built properly: full mortar bed, 100mm of compacted sub-base, and slabs that can take a point load. The calculator above is preset to a typical 3m × 3m tub base — change it to your numbers and the price follows.
What cracks bases
Dot-and-dab bedding, skipped sub-base, and building on unsettled ground. If a quote is suspiciously cheap, one of those three is usually why.
Placement is forever
Once it's full, you're not moving it. Leave 500mm of access on the side with the control panel, and think about the view from in the tub, not just of it.
Keep planning
- The full patio calculatorStart from scratch with your own numbers.Open it →
- New patio over the old one — sometimes brilliant, sometimes a disasterGoing over the top saves the dig-out and the skip. It also raises your levels by 50mm and inherits every problem the old patio has. Here's how to tell which side of that trade you're on.Plan this one →