ᐅ Knee wall windows installed too low—what are your thoughts?

Great stuff! Thank you very, very much!

kevbuildthis schrieb:

Wow, many thanks! What are the current window dimensions you used (width/height) and what is the room size (m²)? It would be great if I could ask you a few more questions in the next days, if you don’t mind, also via private message. 😉

For us, there will be a knee wall height of 2 meters (6.6 feet) minus 16cm (6 inches) floor structure. We are also leaving out the external roller shutter box. The clear structural opening is currently planned at 1.75m (5 feet 9 inches) from the top of the unfinished floor. Minus the floor buildup, this leaves about 1.55m (5 feet 1 inch) in height for the window, with a fixed glazing section at the bottom. Above that, there is a 35° pitched roof with a 40cm (16 inches) roof overhang. The room is approximately 13m² (140 square feet). With a room width of 3.8m (12.5 feet), the window is currently planned to be 2m (6.6 feet) wide.

Naturally, many questions come to mind... How will it look, also from the outside? Is there enough light considering the height and roof overhang? Would a prefab dormer be better...? And so on. I guess you are familiar with almost every thought like this. 🙂

Oh, and I’ll gladly support your next barbecue with a case of local pilsner. 😉

The key measurements can be seen in the pictures. The room is 15m² (161 square feet) with dimensions of about 3.10m by 4.90m (10 feet 2 inches by 16 feet).

The window itself is 1.72m (5 feet 7 inches) wide and 1.72m (5 feet 7 inches) high. The roof slope begins at a height of 1.90m (6 feet 3 inches).

The room is used by our son, who is 13 years old, and he is very happy with the natural light and window height. I am 1.75m (5 feet 9 inches) tall, and when I stand directly in front of the window, it feels quite comfortable; I don’t have to look at a wall.

Our architect called this window a “dwarf window” during the design stage, but by leaving out the roller shutter box—a very good idea—it no longer feels like a dwarf window. We have plenty of light in this room; it was definitely a very good solution. The neighbor, who is our tenant next door, uses this room as an office and is also quite satisfied.

You have less roof overhang and a wider window, and a smaller room, so planning a window like this will not be a problem for you at all.

Installing the external roller shutters was also not an issue. The carpenter cut the rafters at the necessary points so the shutters are barely visible because they are small and well hidden.

There was a question about whether proper insulation could be installed above this window at the roof slope. The drywall installer improvised a bit and was able to insulate very well since there is no ready-made solution for this. A construction needs to be built to insulate and seal that spot, but it wasn’t a big deal.

In summary, the window looks very good from the outside; you can hardly see that it is set a bit deeper than usual, and it fits well with the overall look of the house. It was not as expensive as a prefab dormer or roof window, etc. The external roller shutter cost almost the same as the roller shutter box.

The view through the windows is brilliantly captured – it looks as if each windowpane offers a completely different perspective, as the arrangement of houses, hedges, and gardens is perfectly divided by the window frame.

Great, thank you very much for the support! It looks really good. For us, the height would be about 10cm (4 inches) less, but the width would be slightly larger at around 2m (6.5 feet). It definitely can’t be any less, so a top-mounted roller shutter is definitely not an option. It looks nicely symmetrical on your side as well, also matching the windows below!

May I ask a couple more questions out of curiosity:

Did you build the house yourselves or work with one of the more well-known builders?
What are the dimensions of the double casement windows on the ground floor?

kevbuildthis schrieb:

Great, thank you very much for the support! It looks really good. For us, the height would be about 10cm (4 inches) less, but the width would be a bit wider at 2m (6 ft 7 inches). It definitely can’t be any less than that, so an external roller shutter is definitely out. Your design looks nicely symmetrical, also in relation to the windows below!

May I ask a few more questions out of curiosity:

Did you build it yourselves or work with one of the more well-known home builders?
What are the dimensions of the double casement windows on the ground floor?

Thanks as well!
We subcontracted the trades ourselves and had the architect do the planning and supervise occasionally.

The windows below measure 1.24 x 1.73m (w x h).
Please note that all measurements I provided are finished dimensions, not the rough opening sizes usually shown in construction plans.

Having 10cm (4 inches) less in height won’t be a deal breaker, but try to maximize every centimeter. The key is the clear opening height, not the wall reveal height. Choose windows with narrower frame profiles.
In terms of natural light, your room will be well provided for; as you can see, the ground floor windows are smaller, yet the rooms are still always bright.

Our semi-detached house will be almost identical. If it’s not too much trouble and time permits, could you please take a full side photo showing both houses roughly from the front?

Our entire house will be 16m (52.5 ft) wide, with each half being 8m (26 ft).

The current rough opening dimensions for our standard double casement windows are 162.5cm by 143cm (64 inches by 56 inches). However, I need to double-check what the actual clear opening will be for the windows. It’s quite confusing because the sill height refers to the top of the unfinished floor, but with an 18cm (7 inch) floor buildup, the window would end up quite low. Also, the rough opening height of 143cm (56 inches) does not account for an external roller shutter box for some reason.