ᐅ Building a Sauna Yourself with a Sloped Ceiling – Suggestions, Tips, and Planning Advice
Created on: 24 Nov 2020 10:14
M
matte
Hello! [IMG alt=" 🙂"]https://saunabauen.de/forum/images/smilies/icon_smile.gif[/IMG]
I’d like to start this thread to get help and feedback on my plan to build a sauna myself. Of course, this thread can also be used for any topics related to sauna construction.
We decided to get a sauna, and since a prefabricated kit was not an option and a custom build was too expensive, I decided to take matters into my own hands.
When we built our house three years ago, we reserved space for a sauna at the top near the roof terrace. Unfortunately, instead of a planned flat roof, we had to install a sloped roof to get the building permit / planning permission.
This results in a roof slope with knee wall height of 1.81m (5 ft 11 in) clear height.
There is a floor area of 2.10m (83 inches) wide and 1.91m (75 inches) deep available.
The height is additionally limited by a fresh air vent on the higher side. The bottom edge of the vent is located at 2.05m (6 ft 9 in) above the finished floor level.
My idea is to build the sauna ceiling at 2.05m (6 ft 9 in) height to still be able to access this vent if necessary. According to my plan, the clear interior height inside the sauna would then be about 1.995m (6 ft 6.5 in).
The sauna will be surrounded on three sides by exterior walls (Poroton T9 masonry).
The ceiling is attached directly to the beams and vapor barrier, without counter battens. This was necessary because otherwise the terrace door would not be able to open. The architect missed that... : [IMG alt=":roll:"]https://saunabauen.de/forum/images/smilies/icon_rolleyes.gif[/IMG]
The floor is fine stoneware tiles on a screed layer with underfloor heating.
We have a three-phase power supply with 5x2.5mm² cable and a cable length of about 20m (66 ft). According to an electrician, this line should not restrict the project.
Since space is quite tight, I want to keep the wall construction as thin as possible.
Planned wall build-up:
1. Masonry with plaster
2. Vertical battens (24x48mm / 1x2 inches) with 24mm (1 inch) air gap for ventilation
3. OSB boards 15mm (0.6 inch)
4. KVH timber beams 40x60mm (1.5x2.5 inches), positioned so the 40mm (1.5 inch) side accommodates insulation
5. 40mm (1.5 inch) wood fiber insulation inside
6. No vapor barrier
7. 15mm (0.6 inch) profiled battens mounted horizontally
Now my questions:
1. Is my wall build-up feasible, or am I trying to save too much space? This would leave an interior floor dimension of nearly 1.92m x 1.75m (6 ft 3.5 in x 5 ft 9 in).
I’m 1.84m (6 ft 0.5 in) tall, so I should still have enough room to lie down comfortably.
2. We want to install a full glass door with a side panel to enjoy the outdoor view.
We plan to use 8mm (0.3 inch) tempered safety glass (ESG). Is that okay, or can this cause issues near the heater?
3. How do you connect the glass wall to the sauna structure? I thought about routing a groove around the KVH timber to set the glass in. Is that a good approach?
For the floor, I read that someone placed the glass on a silicone mat which was then trimmed flush. That sounds like a good solution to me.
3. The sauna floor area is 3.34m² (36 ft²) with an interior height of 1.995m (6 ft 6.5 in). Ignoring the slope, that gives a volume of 6.66m³ (235 ft³).
I read that for a glass door you add 1.5m³ (53 ft³) and for a glass wall the area (1.5m² / 16 ft²) multiplied by 1.2 as additional volume.
So, I’d end up with a total volume of 9.66m³ (341 ft³) and chose a 9kW heater accordingly. Does that sound right or oversized? I’m currently leaning towards the "Harvia The Wall" with external control.
4. Due to the heater’s position, there is essentially no room for a heater guard between the glass wall and heater. Is a guard necessary in a private sauna? I’m not too worried about it, but my wife is concerned.
The alternative would be to shift the lower bench slightly under the upper bench and move the heater, which would create space for a guard.
Alternatively, there is a glass protective shield with integrated lighting available that mounts in front of the heater. Would that be enough? I’m not too keen on wooden guards though... [IMG alt=";)"]https://saunabauen.de/forum/images/smilies/icon_wink.gif[/IMG]
5. A coworker recommended bench heights of 60cm and 120cm (24 and 47 inches). That would cause problems with the sauna height. I was thinking about 45cm and 90cm (18 and 35 inches) instead. Since we don’t want it very hot anyway, I see no reason for higher benches.
6. To avoid further reducing the roof slope height, I considered skipping the OSB boards there and mounting the KVH beams directly at a 24mm (1 inch) gap (batten distance) from the ceiling. Any issues with that?
7. We prefer the look of horizontally mounted profiled battens. Any objections? Given the tight space, I would skip additional rear ventilation. From what I’ve read, that’s not strictly necessary.
8. In my case, would it be better to use a different insulation material with a vapor barrier instead of wood fiber insulation?
9. The left wall with the glass door will be clad on the outside with profiled wood boards as well. This way I could install an access panel above the sauna to reach the fresh air vent if needed. Also, I could place the electronics for lighting and audio on the ceiling, making them accessible.
Can I mount the cladding boards directly on the KVH beams, or is an additional counter batten or similar required?
I want the wall to finish flush with the terrace door frame. To prevent the terrace door (especially the handle) from hitting the wall, I plan to install a stopper mounted on the KVH timber there.
That’s it for now. I’m curious what you think about my plan. I hope my post is not too long... [IMG alt=":?"]https://saunabauen.de/forum/images/smilies/icon_confused.gif[/IMG]
I’m attaching some pictures to show the current planning status. If you need more info, just ask.
Looking forward to any feedback [IMG alt=";)"]https://saunabauen.de/forum/images/smilies/icon_wink.gif[/IMG]
Thanks in advance!
Best regards
I’d like to start this thread to get help and feedback on my plan to build a sauna myself. Of course, this thread can also be used for any topics related to sauna construction.
We decided to get a sauna, and since a prefabricated kit was not an option and a custom build was too expensive, I decided to take matters into my own hands.
When we built our house three years ago, we reserved space for a sauna at the top near the roof terrace. Unfortunately, instead of a planned flat roof, we had to install a sloped roof to get the building permit / planning permission.
This results in a roof slope with knee wall height of 1.81m (5 ft 11 in) clear height.
There is a floor area of 2.10m (83 inches) wide and 1.91m (75 inches) deep available.
The height is additionally limited by a fresh air vent on the higher side. The bottom edge of the vent is located at 2.05m (6 ft 9 in) above the finished floor level.
My idea is to build the sauna ceiling at 2.05m (6 ft 9 in) height to still be able to access this vent if necessary. According to my plan, the clear interior height inside the sauna would then be about 1.995m (6 ft 6.5 in).
The sauna will be surrounded on three sides by exterior walls (Poroton T9 masonry).
The ceiling is attached directly to the beams and vapor barrier, without counter battens. This was necessary because otherwise the terrace door would not be able to open. The architect missed that... : [IMG alt=":roll:"]https://saunabauen.de/forum/images/smilies/icon_rolleyes.gif[/IMG]
The floor is fine stoneware tiles on a screed layer with underfloor heating.
We have a three-phase power supply with 5x2.5mm² cable and a cable length of about 20m (66 ft). According to an electrician, this line should not restrict the project.
Since space is quite tight, I want to keep the wall construction as thin as possible.
Planned wall build-up:
1. Masonry with plaster
2. Vertical battens (24x48mm / 1x2 inches) with 24mm (1 inch) air gap for ventilation
3. OSB boards 15mm (0.6 inch)
4. KVH timber beams 40x60mm (1.5x2.5 inches), positioned so the 40mm (1.5 inch) side accommodates insulation
5. 40mm (1.5 inch) wood fiber insulation inside
6. No vapor barrier
7. 15mm (0.6 inch) profiled battens mounted horizontally
Now my questions:
1. Is my wall build-up feasible, or am I trying to save too much space? This would leave an interior floor dimension of nearly 1.92m x 1.75m (6 ft 3.5 in x 5 ft 9 in).
I’m 1.84m (6 ft 0.5 in) tall, so I should still have enough room to lie down comfortably.
2. We want to install a full glass door with a side panel to enjoy the outdoor view.
We plan to use 8mm (0.3 inch) tempered safety glass (ESG). Is that okay, or can this cause issues near the heater?
3. How do you connect the glass wall to the sauna structure? I thought about routing a groove around the KVH timber to set the glass in. Is that a good approach?
For the floor, I read that someone placed the glass on a silicone mat which was then trimmed flush. That sounds like a good solution to me.
3. The sauna floor area is 3.34m² (36 ft²) with an interior height of 1.995m (6 ft 6.5 in). Ignoring the slope, that gives a volume of 6.66m³ (235 ft³).
I read that for a glass door you add 1.5m³ (53 ft³) and for a glass wall the area (1.5m² / 16 ft²) multiplied by 1.2 as additional volume.
So, I’d end up with a total volume of 9.66m³ (341 ft³) and chose a 9kW heater accordingly. Does that sound right or oversized? I’m currently leaning towards the "Harvia The Wall" with external control.
4. Due to the heater’s position, there is essentially no room for a heater guard between the glass wall and heater. Is a guard necessary in a private sauna? I’m not too worried about it, but my wife is concerned.
The alternative would be to shift the lower bench slightly under the upper bench and move the heater, which would create space for a guard.
Alternatively, there is a glass protective shield with integrated lighting available that mounts in front of the heater. Would that be enough? I’m not too keen on wooden guards though... [IMG alt=";)"]https://saunabauen.de/forum/images/smilies/icon_wink.gif[/IMG]
5. A coworker recommended bench heights of 60cm and 120cm (24 and 47 inches). That would cause problems with the sauna height. I was thinking about 45cm and 90cm (18 and 35 inches) instead. Since we don’t want it very hot anyway, I see no reason for higher benches.
6. To avoid further reducing the roof slope height, I considered skipping the OSB boards there and mounting the KVH beams directly at a 24mm (1 inch) gap (batten distance) from the ceiling. Any issues with that?
7. We prefer the look of horizontally mounted profiled battens. Any objections? Given the tight space, I would skip additional rear ventilation. From what I’ve read, that’s not strictly necessary.
8. In my case, would it be better to use a different insulation material with a vapor barrier instead of wood fiber insulation?
9. The left wall with the glass door will be clad on the outside with profiled wood boards as well. This way I could install an access panel above the sauna to reach the fresh air vent if needed. Also, I could place the electronics for lighting and audio on the ceiling, making them accessible.
Can I mount the cladding boards directly on the KVH beams, or is an additional counter batten or similar required?
I want the wall to finish flush with the terrace door frame. To prevent the terrace door (especially the handle) from hitting the wall, I plan to install a stopper mounted on the KVH timber there.
That’s it for now. I’m curious what you think about my plan. I hope my post is not too long... [IMG alt=":?"]https://saunabauen.de/forum/images/smilies/icon_confused.gif[/IMG]
I’m attaching some pictures to show the current planning status. If you need more info, just ask.
Looking forward to any feedback [IMG alt=";)"]https://saunabauen.de/forum/images/smilies/icon_wink.gif[/IMG]
Thanks in advance!
Best regards
Regarding the width of the ventilation cavity, I just can’t make up my mind.
This morning, I came up with the idea to route the supply air for the mechanical ventilation system through a flat duct down to the lower side. The stove is expected to have its air intake on the high wall, so it would take its air from the supply air flowing through all three sides of the ventilation cavity.
The alternative would be to widen the ventilation cavity from 24mm to 38mm (about 1 inch to 1.5 inches). That would add a total of 28mm (about 1.1 inches) on two sides, and I would still have a clear internal width of 1.89m (6.2 ft).
Update: I mocked up the 1.89m (6.2 ft) width with a rolling container placed at the right distance from a wall. No way. It will stay at 28mm (about 1.1 inches) ventilation cavity. Those 3cm (1.2 inches) really make a difference—I even bumped my head pretty hard ^^
This morning, I came up with the idea to route the supply air for the mechanical ventilation system through a flat duct down to the lower side. The stove is expected to have its air intake on the high wall, so it would take its air from the supply air flowing through all three sides of the ventilation cavity.
The alternative would be to widen the ventilation cavity from 24mm to 38mm (about 1 inch to 1.5 inches). That would add a total of 28mm (about 1.1 inches) on two sides, and I would still have a clear internal width of 1.89m (6.2 ft).
Update: I mocked up the 1.89m (6.2 ft) width with a rolling container placed at the right distance from a wall. No way. It will stay at 28mm (about 1.1 inches) ventilation cavity. Those 3cm (1.2 inches) really make a difference—I even bumped my head pretty hard ^^
For us, the house builder installed it during construction. I can’t provide any more specific details, unfortunately. Since we have a timber frame construction, we simply covered it with wood instead of the Fermacell panels usually used. WARNING! If you plan to go to the lumberyard today, make sure to get low-resin wood. It’s really unpleasant if you stick to the wood with resin on your bare skin. Okay, if you want a hairless bottom, you could consider it an alternative sugaring— but I would advise against it.
There is special wood for saunas that has been specially treated. I would have liked to have Swiss pine as well, but my husband finds the smell terrible.
Our sauna is roughly your size, but the roof slope is reversed (you enter from the highest side, and it slopes downward toward the back).
Regarding height: only as high as absolutely necessary. The lower it is, the faster it heats up inside.
The size is enough for two people. We decided on a slightly different "interior layout." Since the sauna is quite small, all benches would have felt cramped either in depth or length. So we chose to create a large lounging surface that is somewhat higher than a normal lower bench (about thigh height). This works perfectly for us because it really provides enough space to lie down. Suitable vendors already offer nearly ready-made bench elements for lounging surfaces. We combined two of these prefabricated elements to form our lounge area. Very practical: when you want to clean underneath, one side simply folds up.
I quickly sketched a plan:
View from outside looking into the sauna:
The large lounging surface (at about 76cm (30 inches) height):
(I would always prefer this over traditional benches in a small sauna! You simply have more space to lie down. Instead of a fixed, space-consuming step, we bought a simple step stool from Ikea; it works great!)
Folded up for cleaning:
(As you can see, it rests on suitably sturdy battens on the sides.)
These parts were purchased ready-made from a sauna manufacturer, ensuring you don’t get resin on your skin.
View from inside while lying or sitting on the lounging surface:
At the back, we placed the lighting where the ceiling slopes:
(It can be white, colored lights, or color-changing.)
We don’t have a sound system. If needed, we could use our USB speaker with a phone to play music in the bathroom, which could be heard inside the sauna too. But we usually just enjoy the quiet for relaxation.
There is special wood for saunas that has been specially treated. I would have liked to have Swiss pine as well, but my husband finds the smell terrible.
Our sauna is roughly your size, but the roof slope is reversed (you enter from the highest side, and it slopes downward toward the back).
Regarding height: only as high as absolutely necessary. The lower it is, the faster it heats up inside.
The size is enough for two people. We decided on a slightly different "interior layout." Since the sauna is quite small, all benches would have felt cramped either in depth or length. So we chose to create a large lounging surface that is somewhat higher than a normal lower bench (about thigh height). This works perfectly for us because it really provides enough space to lie down. Suitable vendors already offer nearly ready-made bench elements for lounging surfaces. We combined two of these prefabricated elements to form our lounge area. Very practical: when you want to clean underneath, one side simply folds up.
I quickly sketched a plan:
View from outside looking into the sauna:
The large lounging surface (at about 76cm (30 inches) height):
(I would always prefer this over traditional benches in a small sauna! You simply have more space to lie down. Instead of a fixed, space-consuming step, we bought a simple step stool from Ikea; it works great!)
Folded up for cleaning:
(As you can see, it rests on suitably sturdy battens on the sides.)
These parts were purchased ready-made from a sauna manufacturer, ensuring you don’t get resin on your skin.
View from inside while lying or sitting on the lounging surface:
At the back, we placed the lighting where the ceiling slopes:
(It can be white, colored lights, or color-changing.)
We don’t have a sound system. If needed, we could use our USB speaker with a phone to play music in the bathroom, which could be heard inside the sauna too. But we usually just enjoy the quiet for relaxation.
I had to look up "sugaring" first 😀
Thanks for your introduction. I really like it.
We were also thinking about having a large lounging area today, but the upper bench is still there, so you could basically tuck your feet under it.
However, I’m wondering if we even need the upper bench. Removing it would make the space look tidier.
I need to discuss this with my wife since I’m not entirely happy with the furnishing, mainly because of the lounging area.
Edit: How wide is your door?
Thanks for your introduction. I really like it.
We were also thinking about having a large lounging area today, but the upper bench is still there, so you could basically tuck your feet under it.
However, I’m wondering if we even need the upper bench. Removing it would make the space look tidier.
I need to discuss this with my wife since I’m not entirely happy with the furnishing, mainly because of the lounging area.
Edit: How wide is your door?
The glass door itself measures 684x1968mm (I have the technical data in front of me right now, so I know this precisely *g*). It cost €183.37 net, including the drillings for the fittings and a handle hole (no other openings are needed, as no additional opener is required).
The opening for the door must be correspondingly larger to accommodate the frame.
The opening for the door must be correspondingly larger to accommodate the frame.
We took the idea of the bench surface from a show home. There, they also had a great sauna heater for small saunas, especially when space is limited:
This would have been our option if there had been little room for the heater. But for us, a standard heater fit just fine. However, it could be an option for you. Unfortunately, I don’t remember the brand.
In the example above, the two stools on the right and left are freely movable.
I wouldn’t need the front panel – I would always wonder what might collect underneath it. I like that in our sauna, it’s easy to clean under there.
If I were you, I would start with just this bench surface. If you later really miss having the upper bench, it’s very easy to add it afterwards.
This would have been our option if there had been little room for the heater. But for us, a standard heater fit just fine. However, it could be an option for you. Unfortunately, I don’t remember the brand.
In the example above, the two stools on the right and left are freely movable.
I wouldn’t need the front panel – I would always wonder what might collect underneath it. I like that in our sauna, it’s easy to clean under there.
If I were you, I would start with just this bench surface. If you later really miss having the upper bench, it’s very easy to add it afterwards.
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