Homeowners · 4 min read · Updated 6 November 2026
Can you put a hired hot tub on decking, a patio, grass or a balcony?
How heavy is a full hot tub?
Water weighs about 1 kg per litre, so hot tubs get very heavy once filled and occupied. These are rough guides.
| Tub | Water | Approximate total with 4 to 6 adults |
|---|---|---|
| 4 to 6 person inflatable | 800 to 1,100 litres | Roughly 1.2 to 1.6 tonnes |
| 6 to 8 person inflatable | 1,000 to 1,300 litres | Roughly 1.4 to 1.8 tonnes |
| 5 to 6 seat hard-shell, plus the empty shell | 1,200 to 1,600 litres plus 250 to 400 kg | Roughly 2 to 2.5 tonnes |
Spread over a footprint of around 3 to 4 square metres, a full inflatable puts roughly 400 to 500 kg on every square metre. That is about three times the load a typical UK domestic floor is designed for, which is why balconies and lightweight decks are a concern.
Base options compared
| Surface | Usually suitable? | Things to check |
|---|---|---|
| Concrete base | Yes, the best option | Level, no cracks, drains away from the house |
| Patio slabs | Usually yes | Level, firmly bedded, no rocking or hollow slabs |
| Block paving | Usually yes | Level and not sunken |
| Decking | Only if strong enough | Joist size, spacing, posts and footings |
| Natural grass | Sometimes, for inflatables | Firm, level, dry ground and a protective mat |
| Artificial grass | Sometimes, for inflatables | What is underneath, and protection against heat and water |
| Gravel | Rarely | Uneven, sharp stones can damage an inflatable |
| Balcony or roof terrace | Rarely | Structural engineer and building owner consent |
Decking: how to tell if it is strong enough
Most garden decking is built for people, furniture and barbecues, not a concentrated load of 1.5 tonnes or more. Older decks may also have soft or rotten joists that are not obvious from above.
- Check the decking is level with a spirit level in several directions
- Look underneath if you can: joists should be sound, closely spaced and supported by posts on solid footings
- Avoid placing the tub in the middle of a long span between supports
- Do not put a tub on decking that flexes, creaks or bounces when you walk on it
- If in doubt, use a patio or concrete area instead, or ask a structural engineer
A layer of boards over the deck does not make a weak deck strong. It only spreads the load slightly.
Grass and artificial grass
Inflatables can sit on firm, level lawns, but the ground needs to be truly flat. A slope of even a few centimetres across the tub puts more water at one side, which can strain the walls and seams. Ground can also soften after rain, and the tub can sink unevenly. Expect a pale, flattened patch of lawn afterwards.
Artificial grass is often laid over sand or a sub-base that may move, and some products can be damaged by heat or chemicals. Use the ground protector supplied and check with your supplier.
Balconies and flats
Balconies are designed for people standing and light furniture. A filled hot tub is far heavier than this and could overload the structure. Most leases for flats also prohibit heavy items, water features or alterations on balconies. Do not put a hot tub on a balcony or roof terrace without written permission from the building owner and a structural engineer's confirmation.
Preparing the spot before delivery
- Clear the area completely, including pots, furniture and stones
- Sweep away anything sharp that could puncture an inflatable
- Check the spot is level, using a long spirit level or a straight board
- Make sure there is a suitable outdoor socket within reach without an extension lead
- Check the hose reaches the tub
- Leave a clear path for the supplier to bring the tub in
Send your supplier a photo of the spot before the hire. Many will tell you straight away whether it looks suitable.
If the only level area is a little uneven, do not try to pack the tub up with bricks or bits of wood. Uneven support can damage an inflatable's floor and put strain on a hard-shell cabinet. A thin layer of sharp sand under a ground protector can even out small dips on a firm base, but anything more than a small dip means the spot is not suitable.
Think about drainage too. Water splashes and drips around a hot tub, and draining at the end of the hire releases hundreds of litres, so avoid placing the tub where water will run towards the house walls or air bricks.
Frequently asked questions
Is decking strong enough for an inflatable hot tub?
Sometimes. A well-built, level deck with sound, closely spaced joists on solid footings may take an inflatable hot tub, but many garden decks are not designed for a concentrated load of 1.2 to 1.6 tonnes or more. If the deck flexes, is old or you cannot see the frame, use a patio or concrete base instead or ask a structural engineer.
Can I put an inflatable hot tub on grass?
Yes, if the ground is firm, level and dry, and you use a ground protector or insulated mat. Lawns often look flat but are not, and soft ground can sink unevenly after rain, straining the tub. Expect a flattened patch of grass afterwards. A patio or concrete base is a more reliable option where one is available.
Can a hot tub go on a balcony?
In most cases, no. A filled hot tub with people in it weighs well over a tonne, which is far more than a typical balcony is designed for. Leases for flats also usually prohibit this. It should only be considered with written consent from the building owner and a structural engineer's confirmation that the balcony can take the load.
decking patio hot tub base weight
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