My Site, My Stuff

Hot-Tub Shack

In 2017, we got an inflatable hot-tub, one of the Lay-Z-Spa range that was on special offer. The idea was that it might help my bad knees and other joints. We used it in the garden for a while but there was no cover and leaves and muck would drop in while we were using it 🙂

There was an odd-shaped corner in the garden which was just overgrown brambles and other non-useful bushes so we thought that might be a good spot for some sort of shelter. It would need clearing and the dwarf-wall removing that formed the narrow raised bed along two sides of the small garden.

The Design

I sketched up a few ideas in a CAD app called Fusion 360, a very powerful app but difficult to master. Part of the chosen design is shown here…

Wood was chosen to make it easy to build and less permanent than brick etc. I planned each wall and the floor as a separate build, the idea was to put it together like a kit when the panels were finished, I work alone so it makes it easier to build bigger projects this way.

Clearing the Area

Clearing the raised bed and altering the dwarf wall was first, I got a contractor in for this as the soil was heavily compacted and solid with tree roots from the trees in the carpark over the fence.

The team at work, nice little digger.

It only took them a day, would have taken me many days of back-breaking digging to do this.

The Build

The next task was digging-in some block supports, the pattern was worked out on the weight of the full tub – about 1000kg, the high-density concrete blocks were bedded on mortar.

Floor support grid.

The floor support joists were 2×4, these were deemed big enough as the heavy weight was well supported directly underneath, treated timber was used throughout. The floor grid was also made as pre-built panels up on trestles – this makes it so much easier to build and no back ache or sore knees. The two clamps shown above are holding the two frames together ready to fix.

Before the floor was laid, the soil was covered in weed control fabric and a layer of ballast to keep it in place, this was done to try and keep weeds at bay.

Floor finished, first wall panel going in

The floor boards are standard 1×4 decking, grooved side up. The boards are fixed with a 5mm gap – I thought this would help if the tub sprung a leak and it also allows air to circulate. Once the floor was down, assembly was easy and very enjoyable.

Coming along nicely

Fitting the pre-built walls was easy, just lift into place, clamp at a corner then screw down to floor and at the corners. The front wall was mostly framing as the doors were large, this was built in-situ. The walls were all treated on the outside before assembly. The roof has a reasonable fall on it, draining to the rear. The front peak was at the maximum allowed for garden structures, this was needed to allow standard UPVC doors to fit.

Roof fitted

The roof is triple-wall polycarbonate. The roof is held on 2×3 timbers, these are at the limit for the span but worked ok. The angled support fixing brackets, just visible in the picture above, were custom made by me in my engineering workshop and powder-coated.

Step fitted

A wide step was fitted, using more decking boards, mostly offcuts from the floor. So far the whole build had been blessed with hot weather, I was getting a pretty good tan out there 🙂

The doors were the hardest part, they are very large and had side-panels. They came as a set of frame bars and panels but the double doors were one unit and extremely heavy. I de-glazed all the panels so they were easier to lift but even the empty door frame was a task.

All done


In the end the project was a total success, it has extended our hot-tub year well into the cooler months, we drain it in October and refill in March. Its a great way to unwind and spend a few hours in peace and quiet. Being sheltered also reduces heat-loss from the tub and therefore its running costs as well, in 2020 it was costing about £8-10 per week to run it, left on 24/7 at 38C.