ᐅ Single-family house, single-story, knee wall, upper floor windows
Created on: 27 May 2016 19:05
M
molchiHello, good evening!
I would like to thank all active members and moderators here once again, as I have already received some good advice just by quietly reading along. However, we are currently struggling with questions that cannot, at least for me, be clarified on the internet.
Here is the situation:
Planning a single-family house with very tight specifications
Maximum house footprint: 121m² (1300 ft²)
One story
Lower Saxony
We would like to have a dormer on one side and narrow windows in the knee wall on the other side, if possible. Unfortunately, we have encountered conflicting information from architects, so I would like to ask the following questions:
Which parameters are taken into account when calculating the upper floor, in order to make the best possible use of the knee wall height?
The Lower Saxony building code states that a full floor requires a clear height of at least 2.20m (7.2 ft) over two-thirds of the floor area.
I also know that the external thickness of the gable wall is not included in the calculation.
Are there other factors that should be considered to maximize the upper floor area, such as stair openings, interior walls, or similar?
From what knee wall height or under which conditions are narrow windows on the roof slope side allowed on the upper floor, or are they impossible in a single-story building?
If you need any additional information about our project, please let me know!
Sorry for my non-expert terminology!
Good luck
Tom
I would like to thank all active members and moderators here once again, as I have already received some good advice just by quietly reading along. However, we are currently struggling with questions that cannot, at least for me, be clarified on the internet.
Here is the situation:
Planning a single-family house with very tight specifications
Maximum house footprint: 121m² (1300 ft²)
One story
Lower Saxony
We would like to have a dormer on one side and narrow windows in the knee wall on the other side, if possible. Unfortunately, we have encountered conflicting information from architects, so I would like to ask the following questions:
Which parameters are taken into account when calculating the upper floor, in order to make the best possible use of the knee wall height?
The Lower Saxony building code states that a full floor requires a clear height of at least 2.20m (7.2 ft) over two-thirds of the floor area.
I also know that the external thickness of the gable wall is not included in the calculation.
Are there other factors that should be considered to maximize the upper floor area, such as stair openings, interior walls, or similar?
From what knee wall height or under which conditions are narrow windows on the roof slope side allowed on the upper floor, or are they impossible in a single-story building?
If you need any additional information about our project, please let me know!
Sorry for my non-expert terminology!
Good luck
Tom
It’s about the interior space, if I remember correctly... The staircase and so on don’t matter.
It depends somewhat on what type of windows you want... For example, a window in the stairwell is possible – but regular windows are difficult. What’s the point of a window you can’t look out of?
Do you have 121 m² (1300 sq ft) of floor area for the house, or 121 m² (1300 sq ft) of buildable area?
A common tip is to add a “conservatory” or something similar on the ground floor to artificially increase the floor area. However, this somewhat conflicts with your 121 m² (1300 sq ft) limit.
Do you have any requirements regarding other heights? (Ridge height, eaves height, etc.)?
It depends somewhat on what type of windows you want... For example, a window in the stairwell is possible – but regular windows are difficult. What’s the point of a window you can’t look out of?
Do you have 121 m² (1300 sq ft) of floor area for the house, or 121 m² (1300 sq ft) of buildable area?
A common tip is to add a “conservatory” or something similar on the ground floor to artificially increase the floor area. However, this somewhat conflicts with your 121 m² (1300 sq ft) limit.
Do you have any requirements regarding other heights? (Ridge height, eaves height, etc.)?
Hey!
121 m² (1300 sq ft) as the floor area ratio 1, for the house footprint.
However, we need every square meter of living space since we have many children, so no conservatory.
We really like the slightly deeper narrow windows, so we would prefer them over skylights, compared to dormers, on the sloped roof side.
There are no written regulations regarding ridge height, eaves height, or knee wall height, unless some general clause in Lower Saxony forbids it.
Only single-story and a maximum of two units per house.
Now I would like to know how to make the best use of the upper 2/3.
Good luck
Tom
121 m² (1300 sq ft) as the floor area ratio 1, for the house footprint.
However, we need every square meter of living space since we have many children, so no conservatory.
We really like the slightly deeper narrow windows, so we would prefer them over skylights, compared to dormers, on the sloped roof side.
There are no written regulations regarding ridge height, eaves height, or knee wall height, unless some general clause in Lower Saxony forbids it.
Only single-story and a maximum of two units per house.
Now I would like to know how to make the best use of the upper 2/3.
Good luck
Tom
Regarding the knee wall windows: I wanted them mainly for the aesthetics. The downside is that with a low knee wall, you have about 30 cm (12 inches) of parapet height with a 70 cm (28 inches) window height (rough opening). Above that is the lintel... This leads to a knee wall height of about 130 cm (51 inches). The window would then have to be fixed glazing for safety reasons.
What does this mean for a typical room? Less usable wall space. An additional light source besides another window. Otherwise, nothing.
We wanted it opposite the staircase in the gallery for the view—we don’t need space for separate rooms since it’s just the two of us.
My advice would be: skip it and use the space for usable floor area instead!
Regarding single-story design:
@BeHaElJa achieved single-story living with about a 160 cm (63 inches) knee wall.
A 120 sqm (1,292 sq ft) buildable area usually results in about 80–90 sqm (860–970 sq ft) of living space in a timber frame house, with a similar floor area upstairs. A 160 cm (63 inches) knee wall provides nearly full-height living space. Children can walk all the way to the wall, and an adult can, too, if there is a wardrobe against the wall.
You can also position the window bands higher, ensuring children and even seated adults have a clear view outside.
Since people usually don’t stand directly in front of a window, the lintel doesn’t disturb the view and generally doesn’t block the sightline. The view is slightly oriented downward, not toward the sky.
Therefore... with a 160 cm (63 inches) knee wall... it’s better than skylights!
What does this mean for a typical room? Less usable wall space. An additional light source besides another window. Otherwise, nothing.
We wanted it opposite the staircase in the gallery for the view—we don’t need space for separate rooms since it’s just the two of us.
My advice would be: skip it and use the space for usable floor area instead!
Regarding single-story design:
@BeHaElJa achieved single-story living with about a 160 cm (63 inches) knee wall.
A 120 sqm (1,292 sq ft) buildable area usually results in about 80–90 sqm (860–970 sq ft) of living space in a timber frame house, with a similar floor area upstairs. A 160 cm (63 inches) knee wall provides nearly full-height living space. Children can walk all the way to the wall, and an adult can, too, if there is a wardrobe against the wall.
You can also position the window bands higher, ensuring children and even seated adults have a clear view outside.
Since people usually don’t stand directly in front of a window, the lintel doesn’t disturb the view and generally doesn’t block the sightline. The view is slightly oriented downward, not toward the sky.
Therefore... with a 160 cm (63 inches) knee wall... it’s better than skylights!
Actually, the floor area ratio indicates the area that may be built on, including access paths – but I could be mistaken. Often, there is a 50% allowance for access paths; however, the terrace is usually counted as part of the house.
The longer the house, the higher the knee wall can be (but the space in between becomes correspondingly narrower).
The longer the house, the higher the knee wall can be (but the space in between becomes correspondingly narrower).
That’s why I want the knee wall as high as possible.
A height of 130cm (51 inches) would actually feel too much like a submarine.
The narrow window in the knee wall is just meant for the bathroom, above the bathtub. I prefer not to rely on skylights.
The question now is, since the upper floor is actually about 81m² (872 sq ft), how can this area still be increased? Should you calculate two-thirds of the gross floor area downstairs and take that result as the net area upstairs, meaning you distribute that result across the total floor space of all rooms upstairs? That way, you would exclude not only the exterior walls but also the interior walls.
Are there other options to expand the upper floor area, like using the stairwell opening or the broom closet (just throwing ideas around)?
What do you mean, Yvonne, about installing floor-to-ceiling windows with a 160cm (63 inches) knee wall? And does BeHaElja have a dormer (or not) on the opposite side?
That’s right, the floor area ratio 2 then specifies how large the ancillary buildings (garage, access paths, etc.) are allowed to be. These would be your mentioned 50% exceedances.
For the terrace, I would consider grass! Otherwise, it won’t add up!
A height of 130cm (51 inches) would actually feel too much like a submarine.
The narrow window in the knee wall is just meant for the bathroom, above the bathtub. I prefer not to rely on skylights.
The question now is, since the upper floor is actually about 81m² (872 sq ft), how can this area still be increased? Should you calculate two-thirds of the gross floor area downstairs and take that result as the net area upstairs, meaning you distribute that result across the total floor space of all rooms upstairs? That way, you would exclude not only the exterior walls but also the interior walls.
Are there other options to expand the upper floor area, like using the stairwell opening or the broom closet (just throwing ideas around)?
What do you mean, Yvonne, about installing floor-to-ceiling windows with a 160cm (63 inches) knee wall? And does BeHaElja have a dormer (or not) on the opposite side?
That’s right, the floor area ratio 2 then specifies how large the ancillary buildings (garage, access paths, etc.) are allowed to be. These would be your mentioned 50% exceedances.
For the terrace, I would consider grass! Otherwise, it won’t add up!
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