What does a hot tub need to stand on?
The base is the first thing you need to sort out, and usually the only thing that has to be finished before we arrive. Here is what a hot tub and a sauna need to stand on — and what you should raise with us if your plot is steep, soft or exposed to the weather.
How big does the base have to be?
A hot tub is approx. 2 metres in diameter on the outside. The deck therefore has to be at least 2 × 2 metres.
We recommend 3 × 4 metres. That leaves room for the steps, and lets you walk round the tub without balancing on the edge. The last point matters more than people think, especially in winter.
If you have chosen a hot tub with an external wood-burning stove, the stove needs room too. In that case you need approx. 300 cm in total. The stove has to sit at the same height as the hot tub, and it needs a suitable spot beside the deck.
How much does the base have to take?
This is the figure that decides it. A hot tub holds approx. 1 200 litres of water. The base has to carry the tub filled with water — and everyone sitting in it as well.
Water is heavy, and the weight sits on a small area. Decking that is perfectly pleasant to walk on is not necessarily built for this. If you are in any doubt about whether your existing decking will take it, ask a joiner, or send us a photo and we will look at it together.
If you are wondering about the weight of the model you have chosen, just ask and we will give you the figure.
Decking, concrete or gravel?
We get this question in many forms. The answer is not one particular material. There are three requirements to meet, whatever you build:
- It has to carry the load. The base has to take the filled tub over time, not just on the day it is set down.
- It has to be level. A hot tub that sits askew sits askew at the waterline too — and you see it every single time you bathe.
- It has to be stable. The base must not settle or slide when the frost comes out of the ground in spring.
Timber decking
The most common solution, and the one that gives the best-looking result around the tub. Remember that the deck has to be dimensioned for the filled weight, not for ordinary decking use.
Concrete or paving slabs
A cast slab or a well-laid bed of paving is stable and takes a lot. Watch the fall, so that the water runs away from the tub instead of standing underneath it.
Gravel and shingle
Many cabins already have a gravelled area that looks like the perfect spot. Whether it will do depends on how well compacted and drained it is, and on what lies underneath. That is not something we can answer without seeing the place. Take a photo and send it to us with your enquiry, and we will tell you what we think.
The water has to get away
It gets wet under a hot tub. Water is splashed, it spills over, and sooner or later the tub is drained. Make sure the water has somewhere to go, and that it does not sit between the base and the tub. Good drainage is what decides how long the woodwork underneath stays in good condition.
What does the sauna stand on?
Our saunas stand on point foundations. These have to be in place before we arrive with the sauna.
If you need the measurements to position the foundations correctly — external dimensions, internal dimensions and where the legs sit — ask us about the model you are considering, and we will send you what you need.
If you are putting up a sauna, check whether you have to apply as well: Do I need a planning application?
Steep plot, bedrock or a lot of wind?
If the sauna is going on a slope, is to be fixed to bedrock, or will stand somewhere exposed to the weather, there is no single standard answer. Tell us what the site looks like, ideally with a photo, when you request a quote. Then we can answer for your plot instead of guessing.
We can build the base for you
If you would rather not do the job yourself, we can help you with the deck and the foundation. Tell us where the hot tub or the sauna is going, and we will give you a price.
Do this before we arrive
- Prepare a base of at least 2 × 2 metres for the hot tub — ideally 3 × 4 metres.
- Check that the base will take the tub filled with approx. 1 200 litres of water.
- Put the sauna’s point foundations in place.
- Allow room for the external stove, at the same height as the tub.
- Book a crane or tractor for the lift.
How the delivery itself works is set out in How your sauna gets to you. You will find the same thing in brief under Foundations and preparation.