Leil® Black Cube Premium 4–6 Person Outdoor Sauna Kit

Yes. This kit includes a floor-integrated HUUM DROP 9kW electric heater, sauna stones and UKU Glass WiFi control.

Final electrical connection must be completed by a qualified electrician.

The Premium features a completely redesigned interior with face-to-face opposing benches (instead of L-shaped), three-level seating (instead of two), a stunning Deconord hexagonal decorative back wall, a floor-embedded heater with guard (instead of wall-mounted) and 4 strips of dimmable LEDs (instead of 2). The 1.3m straight benches accommodate 4-6 people compared to the Classic's 4. The exterior dimensions and build quality remain the same excellent standard.

The Black Cube is delivered on a large pallet weighing approximately 750kg, using a tail lift truck. Upon arrival, the pallet will be transferred onto a pump truck trolley and carefully wheeled onto the tail lift. The tail lift will then be lowered, and our driver will move the pallet as far into your driveway as possible. Please note: if you have a gravel driveway, this may present a challenge for the trolley. To help ensure smooth delivery, we recommend laying down mats or boards in advance if you'd like the pallet wheeled across the gravel.

The pallet measures approximately 1.2m (H) x 1.2m (D) x 2.12m (L). You'll need enough space on your driveway for it to be dropped off. If that's not possible, our drivers will leave it kerbside, and it will need to be unpacked by hand—either by you or our assembly team.

While it's technically possible to assemble the sauna yourself, we strongly recommend having a qualified carpenter or joiner assist you—especially if you don't have prior experience with carpentry or working with wood. The assembly manual is detailed and user-friendly for those familiar with construction, but without that background, the process can be challenging and time-consuming. Most of our customers choose professional installation for peace of mind and to ensure everything is assembled correctly. Please note: improper assembly or failure to follow the manual may void the warranty, so if in doubt, we recommend seeking professional help.

Assembly for this model starts at £1,500 + VAT. The final cost depends on your location, as prices increase the further our team travels from London. A team of three carpenters will usually build it in one full day.

Use the Request an Installation Quote button above the options and complete the form with your postcode, access and site details. We will confirm the exact installation price from that information. Installation is invoiced separately and typically arranged closer to the delivery date. You can use a local carpenter, but our team has extensive experience assembling this model.

Typically, it takes around 30 minutes to reach 80°C. However, this can vary depending on factors such as the outside temperature, wind conditions, ventilation settings, and the intensity level you choose. Most customers report their sauna reaches the desired temperature within 20-30 minutes.

The Premium's face-to-face bench layout comfortably seats 4-6 people thanks to the 1.3m long opposing benches. The three-level design lets guests choose their preferred heat intensity, while the layout creates a more social atmosphere compared to the Classic's L-shaped two-level arrangement.

When planning the base for your Black Cube, there are two key requirements to keep in mind. First, the base must be completely level, and secondly, it must be able to support the weight of the sauna and the maximum number of users. The sauna itself weighs 750kg, so be sure to account for an additional 400kg for users when choosing your base material. This can include concrete, patio decking, tiles, asphalt, and more, as long as it is flat and sturdy enough to hold up to 1,150kg. To avoid any potential issues, it is recommended to avoid placing the base on a slope or an area prone to water pooling.

Flat-pack saunas cannot be pre-treated before assembly, because the treatment would be damaged during the assembly process.

Once assembled, the sauna should be treated in line with the manufacturer’s recommendations in the manual, usually by coating the interior and exterior timber with a sauna-suitable treatment as a minimum.

After that initial treatment, owners should expect ongoing maintenance and be prepared to inspect and re-treat exposed timber at least every 12 months, or sooner if local conditions or the manual require it.

Door and hinge alignment may also need minor adjustment over time in line with the manual. In coastal or sea-air environments, exposed metal parts should be protected with a rust-proof treatment such as WD-40 or another suitable anti-corrosion product.

Sauna heaters also require maintenance in line with the manufacturer manual. This normally includes periodically checking, washing, and restacking the stones, and in the longer term electric heater elements may need replacing if they wear out.

If you use our installation team, they can also paint or treat the sauna for you, provided the treatment product is supplied. We do not currently offer a formal maintenance programme.

If your sauna has exposed or untreated exterior timber, use a breathable, UV-resistant and water-resistant exterior wood treatment. We recommend Tikkurila Valtti Plus Kesto or Tikkurila Valtti Plus Color. If you prefer a clear, natural finish, Osmo UV Protection Oil is a good option.

Apply the treatment after assembly and before regular use, then inspect the timber annually and re-treat it as required for the product and your site’s exposure.

For sauna-room walls, window frames and door frames, use Tikkurila Supi Sauna Finish or Tikkurila Supi Sauna Wax. For benches and backrests, use Tikkurila Supi Laudesuoja Bench Protection. Never use ordinary exterior paint, varnish or household wood treatments inside the heated sauna room.

If your sauna has factory-finished or specialist cladding, follow the supplied manual and do not overcoat it unless the manufacturer confirms the product is suitable.

These recommendations are general guidance. Check both the sauna manufacturer’s manual and the treatment manufacturer’s instructions, and satisfy yourself that the product is suitable for the timber and any existing finish before applying it. If you are unsure about a colour, request samples from the manufacturer or retailer and test one on a spare timber offcut or a small, inconspicuous area first.

Buy two 0.9-litre tins (1.8 litres total) of Tikkurila Supi Sauna Finish for the sauna-room walls and ceiling, and one 1-litre tin (1 litre total) of Tikkurila Supi Laudesuoja for the benches and backrests.

The black exterior is factory-treated, so do not overcoat it with a different system. The exposed timber is approximately 11.58 m²; at 8 m² per litre plus 15% allowance, one follow-up coat needs about 1.67 litres. Confirm and buy the matching Leil/Remmers finish supplied for the cabin.

The buying calculation uses 12.47 m² interior requiring 1.79 litres, and 4.42 m² of bench timber requiring 0.64 litres. It uses the lower published coverage rate and one coat inside, with a 15% allowance. Glass, roof shingles or membranes, the underside and confirmed factory-painted trim are excluded.

These are conservative buying allowances. Follow the current label and technical sheet for the product you choose; if its coverage or coat count differs, use those figures instead.

Most simply put, it's not necessary. This is a compact sauna, the thermowood is 40mm thick and has excellent insulation properties, and the sauna is designed to minimise heat loss.

If you are handy with tools and have someone helping you, it could be done in a couple of days. However, most do it in a week or so. Our install team will do it in one day.

No, however, you must get a qualified electrician to connect your heater to your power supply. You will need an isolator as a minimum.

The sauna requires a qualified electrician to install. Wiring details are provided in the manuals under the "Electrical Supply" section. The heater is 9kW and can operate on a single-phase or three-phase setup. Make sure your electrician reviews the UKU control manual and HUUM Drop heater manual.

We do not currently have a full showroom, but many of our existing customers are happy to show their sauna to prospective buyers.

If you would like to see one in person, please contact us and we can try to arrange a viewing with a customer in or near your area.

Unfortunately not. These are prepackaged kits which are sitting in our warehouse and ready to go. We believe that everything in the kit is perfect for this sauna. If you would like to choose your own specification, you could look at the Dice range which is customisable.

The Black Cube features thicker wood, a WiFi-enabled heater, and a sleek black design. The Camilla is more budget-friendly but lacks some of these premium features, though it does have a more traditional look.

You can control the sauna from anywhere via the HUUM smartphone app, as long as your heater is connected to your home WiFi and your phone has internet.

The WiFi controller only supports 2.4GHz networks. Almost all routers have both 2.4GHz and 5GHz networks nowadays, so the UKU control panel must be connected to the 2.4GHz option.

We provide a 2-year warranty when installed by a professional or approved installer. If you choose to self-assemble, the warranty period is 1 year. The HUUM heater comes with its own 5-year manufacturer warranty. You must treat the wood inside and out with appropriate breathable oil after assembly to maintain warranty coverage.

No. Our installation team can assemble the sauna, but the heater and any other electrical components must still be connected by a qualified electrician.

You will need a suitable electrical supply and, at minimum, an isolator switch. Full details are provided in the Electrical Supply section on the product page.

Yes. Any qualified electrician should be able to connect the sauna, provided they follow the electrical requirements listed in the Electrical Supply section of the product page.

After you place your order, we also send further information that you can pass on to your electrician.

In some cases, we may be able to share details of electricians who have connected saunas for previous customers.

Availability will depend on your location, and you are also welcome to use your own qualified electrician.

Assembly time depends on the model, access and site conditions. Many outdoor saunas can be assembled in around one day, while larger or more complex models may take longer.

Use the Request an Installation Quote button above the options and complete the form. We will confirm the expected installation time with your quote.

Yes. Our installation team uses specialist carpenters and installers who are experienced in assembling outdoor saunas, which is one of the reasons many customers prefer professional installation.

No. We do not carry out site visits.

To request an installation quote, use the Request an Installation Quote button above the options and complete the form with photos, measurements, site plans, access details and the proposed sauna location. Our installation team will use that information to assess access, base preparation and positioning, and flag any obvious issues before installation.

In outdoor saunas, it is normal for the timber structure to respond to changes in temperature, humidity, and ambient conditions over time. This can occasionally cause minor movement in the door opening, which may affect how the door closes or sits within the frame.

For this reason, sauna door hinges are designed to be adjustable. Minor door or hinge alignment adjustments over time are normal and should be carried out in line with the manual as part of routine ownership maintenance, rather than being treated as a product fault.

Yes. Outdoor saunas are not maintenance-free.

As a minimum, owners should expect to inspect and re-treat exposed timber at least every 12 months, or sooner if the manufacturer manual and local conditions require it.

You should also expect to make minor door or hinge adjustments over time in line with the manual, as timber structures naturally move slightly with changes in temperature and humidity.

In coastal or sea-air environments, exposed metal parts should be checked more regularly and protected with a rust-proof treatment such as WD-40 or another suitable anti-corrosion product.

Sauna heaters also require maintenance in line with the manufacturer manual. This normally includes periodically checking, washing, and restacking the stones, and in the longer term electric heater elements may need replacing if they wear out.

We do not currently offer a formal maintenance programme.

Our kit saunas are pre-packaged, in-stock models that are ready to go. We import them in bulk and keep them in our UK warehouse, which helps reduce delivery costs and makes them much quicker to dispatch.

Because the kit version is already specified and held in stock, it will always be the better-value option compared with the equivalent made-to-order version, and it is the fastest way to get your sauna delivered.

The non-kit versions are made to order, so they can be customised more, but they normally take around 4 to 6 weeks and will be more expensive.

Yes. Our traditional saunas are suitable for commercial use, and we already supply many commercial customers.

Commercial use requires a regular maintenance regime, as it would with any sauna. This includes cleaning the sauna, inspecting and maintaining the heater stones, and re-treating or painting the timber when required. The frequency will depend on usage, location and the manufacturer's maintenance instructions.