ᐅ Building a Sauna Yourself with a Sloped Ceiling – Suggestions, Tips, and Planning Advice
Created on: 24 Nov 2020 10:14
M
matteHello! [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
Nice project. Something like this will be coming up for me sometime as well.
The stove with 9kW is properly chosen. The electrical circuit must additionally have a 4-pole RCD 25/003A to be on the safe side.
Depending on the cable length, install at least 5x2.5mm² (if not already present) and protect with a 3x16A circuit breaker.
The stove with 9kW is properly chosen. The electrical circuit must additionally have a 4-pole RCD 25/003A to be on the safe side.
Depending on the cable length, install at least 5x2.5mm² (if not already present) and protect with a 3x16A circuit breaker.
Thanks, the cable is 5x2.5mm², approximately 20m (65.6 ft) long. It is also connected separately to 3x16A circuit breakers.
The main question for me is about the wall structure and whether everything will work as planned. Since the space is quite limited, every centimeter (inch) counts...
The main question for me is about the wall structure and whether everything will work as planned. Since the space is quite limited, every centimeter (inch) counts...
P
pagoni202024 Nov 2020 12:43We had a similar idea back then and more or less just started building. We doubled the thickness of the three concrete walls in the basement with 6 x 4cm (2.4 x 1.6 inches) timber studs and made almost the entire front out of glass. Between the glass and the studs we installed insulation, and on top of that an aluminum cladding, battens, and profiled boards. We customized the benches, making them wider than usual, using sauna-grade wood.
In my opinion, the wall construction is sufficient; even our later outdoor sauna had only a 44mm (1.7 inch) wooden wall and an 8kW stove, and everything worked perfectly, even in the coldest winter.
We had double-glazed windows (for some reason?), but the glass next to the stove would get very hot on the outside, which I wouldn’t want. Also, the stove is visible from the outside and there is a view slightly under the bench; therefore, I would consider installing normal cladding or plaster on the lower half and placing glass only on the upper part. This way you avoid the heat issue at the lower level while still maintaining a good view outside. You could also possibly mount the stove on the front wall.
For fixing the glass, either do it as described or use very small square wooden battens on both sides to hold the glass. We used solid structural timber (KVH) as a continuous sill at the bottom and set the glass on it. The sill also served as a stop for the sauna door, but that’s a matter of personal preference. Back then, we mainly learned by doing.
The 9kW stove should definitely be sufficient. Ours also had a steam function, which was useful because sometimes we didn’t want it too hot. Plus, the sauna is indoors, so the room already maintains a certain temperature, unlike an outdoor sauna.
The stove itself gets hot everywhere, and even if you buy a protective cover or similar, you still have to be careful — but that’s always the case. Because of that, I would skip any special additional safety measures.
We spent a lot of time considering the height as well. Eventually, we sat down in the finished room and followed our gut feeling. In my opinion, you should be able to sit comfortably upright on the upper bench and still have a few pleasant centimeters (inches) of clearance to the ceiling. This naturally determines the bench height, which you can adjust as you like. Installing the paneling horizontally is also possible, and I don’t see any problem with it. As I said, this is for private use, not a commercial facility running 12 hours a day continuously under high humidity. Therefore, insulation, ventilation, and moisture control are important, but since you are always there, you can monitor these factors closely. We had our sauna in the basement for years without any issues with mold or moisture. You also have a door to the outside next to it, and the sauna door itself can be left open after use or during the day. If you have a few centimeters (inches) less insulation, it just means the sauna heating will consume a bit more energy — roughly speaking, about 50 cents more on your electricity bill.
If I were you, I would prefer to have those extra centimeters (inches) on the inside. When you apply the aluminum cladding or similar, moisture won’t penetrate. Your plan already takes many important points into consideration, so I wouldn’t worry about implementing it as planned.
However, I would recommend having a steam function for the stove since sometimes you may not want it too hot.
Regarding audio, we installed it under the bench on the floor. It only gets lukewarm there, so theoretically you could place or install a Wi-Fi speaker or similar device in that spot.
In my opinion, the wall construction is sufficient; even our later outdoor sauna had only a 44mm (1.7 inch) wooden wall and an 8kW stove, and everything worked perfectly, even in the coldest winter.
We had double-glazed windows (for some reason?), but the glass next to the stove would get very hot on the outside, which I wouldn’t want. Also, the stove is visible from the outside and there is a view slightly under the bench; therefore, I would consider installing normal cladding or plaster on the lower half and placing glass only on the upper part. This way you avoid the heat issue at the lower level while still maintaining a good view outside. You could also possibly mount the stove on the front wall.
For fixing the glass, either do it as described or use very small square wooden battens on both sides to hold the glass. We used solid structural timber (KVH) as a continuous sill at the bottom and set the glass on it. The sill also served as a stop for the sauna door, but that’s a matter of personal preference. Back then, we mainly learned by doing.
The 9kW stove should definitely be sufficient. Ours also had a steam function, which was useful because sometimes we didn’t want it too hot. Plus, the sauna is indoors, so the room already maintains a certain temperature, unlike an outdoor sauna.
The stove itself gets hot everywhere, and even if you buy a protective cover or similar, you still have to be careful — but that’s always the case. Because of that, I would skip any special additional safety measures.
We spent a lot of time considering the height as well. Eventually, we sat down in the finished room and followed our gut feeling. In my opinion, you should be able to sit comfortably upright on the upper bench and still have a few pleasant centimeters (inches) of clearance to the ceiling. This naturally determines the bench height, which you can adjust as you like. Installing the paneling horizontally is also possible, and I don’t see any problem with it. As I said, this is for private use, not a commercial facility running 12 hours a day continuously under high humidity. Therefore, insulation, ventilation, and moisture control are important, but since you are always there, you can monitor these factors closely. We had our sauna in the basement for years without any issues with mold or moisture. You also have a door to the outside next to it, and the sauna door itself can be left open after use or during the day. If you have a few centimeters (inches) less insulation, it just means the sauna heating will consume a bit more energy — roughly speaking, about 50 cents more on your electricity bill.
If I were you, I would prefer to have those extra centimeters (inches) on the inside. When you apply the aluminum cladding or similar, moisture won’t penetrate. Your plan already takes many important points into consideration, so I wouldn’t worry about implementing it as planned.
However, I would recommend having a steam function for the stove since sometimes you may not want it too hot.
Regarding audio, we installed it under the bench on the floor. It only gets lukewarm there, so theoretically you could place or install a Wi-Fi speaker or similar device in that spot.
Wow. @pagoni2020 Thanks for the helpful feedback! Regarding the steam function, you’ve got me interested again, so we’ll have to reconsider that.
Thanks for the tip about the audio. I’ll probably go with a Sonos Play1, which is also suitable for humid rooms, and place it on the floor under the bench—simple and effective.
You mentioned it: design is important to us, which is why we originally planned a full glass front.
However, since that would prevent us from placing a dresser on the deeper side, we moved the glass wall inward.
Basically, I like the idea of a window above the stove (with the stove then on the wall with the door), but wouldn’t that make it even warmer than the stove as currently planned?
The advantage would definitely be that the stove is farther away from the benches.
I still need to think about that.
I actually want to avoid increasing the air gap. As I said, every extra centimeter is basically too much...
But I will probably play it safe and use a vapor barrier. I still need to decide what insulation material to use—I don’t want to deal with itchy mineral wool 😀
We’ll see what other options there are.
What’s your opinion on the exterior cladding of the visible wall?
Can I screw the profile boards directly onto the KVH (structural timber), or should I add counter battens or something similar? This affects the usable depth of the interior cabin, so I’m a bit anxious about it... 😀
I’d also be interested in opinions about the missing OSB panel on the ceiling slope. However, I’m starting to consider it—in the end, it’s only 15mm (0.6 inches) of height lost, so I don’t think it makes much difference.
Thanks for the tip about the audio. I’ll probably go with a Sonos Play1, which is also suitable for humid rooms, and place it on the floor under the bench—simple and effective.
You mentioned it: design is important to us, which is why we originally planned a full glass front.
However, since that would prevent us from placing a dresser on the deeper side, we moved the glass wall inward.
Basically, I like the idea of a window above the stove (with the stove then on the wall with the door), but wouldn’t that make it even warmer than the stove as currently planned?
The advantage would definitely be that the stove is farther away from the benches.
I still need to think about that.
Mycraft schrieb:
Yes, that’s what I thought too. However, I would leave a bit more air gap to the exterior wall and definitely build with a vapor barrier. Why the decision/thought to skip it?
Otherwise, the wall structure looks fine.
I actually want to avoid increasing the air gap. As I said, every extra centimeter is basically too much...
But I will probably play it safe and use a vapor barrier. I still need to decide what insulation material to use—I don’t want to deal with itchy mineral wool 😀
We’ll see what other options there are.
What’s your opinion on the exterior cladding of the visible wall?
Can I screw the profile boards directly onto the KVH (structural timber), or should I add counter battens or something similar? This affects the usable depth of the interior cabin, so I’m a bit anxious about it... 😀
I’d also be interested in opinions about the missing OSB panel on the ceiling slope. However, I’m starting to consider it—in the end, it’s only 15mm (0.6 inches) of height lost, so I don’t think it makes much difference.
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