Hello,
our roller shutters do not completely block out the light.
I have now noticed that although the shutter closes down to the aluminum window sill, the guides do not extend onto the window sills, leaving a gap on the side through which a significant amount of light comes in.
In another house, I saw that the guides run down onto the window sills and are therefore completely light-tight.
Attached is a photo.
Is this installation correct, or are the guides too short?
These are aluminum roller shutters, in a prefab house.
What do the experts say?

our roller shutters do not completely block out the light.
I have now noticed that although the shutter closes down to the aluminum window sill, the guides do not extend onto the window sills, leaving a gap on the side through which a significant amount of light comes in.
In another house, I saw that the guides run down onto the window sills and are therefore completely light-tight.
Attached is a photo.
Is this installation correct, or are the guides too short?
These are aluminum roller shutters, in a prefab house.
What do the experts say?
N
nordanney24 Jun 2025 10:51Maulwurfbau schrieb:
The construction company says it must be this short because of water, so it doesn’t accumulate there.Did they perhaps create a defect? No second sealing layer installed? No slope on the windowsill?The argument doesn’t make sense.
M
Maulwurfbau24 Jun 2025 10:53It is sealed, and there is also a slope included.
But if this now means that 20 windows on the house would have to be removed, my goodness. They will never do that.
But if this now means that 20 windows on the house would have to be removed, my goodness. They will never do that.
Musketier schrieb:
I recalled that there was a similar topic before:
ᐅ Roller shutters let through a lot of light I also wrote there that ours is just as short but closes darkly.
However, the original post contains photos that are not mine.
Maulwurfbau schrieb:
The construction company says it has to be this short because of water, so it doesn’t accumulate there. I think the same.
M
Maulwurfbau24 Jun 2025 16:28Okay, thanks for the feedback.
I will take a look at the post.
I will take a look at the post.
Here are examples from the RAL guide.
According to it, both options are permissible.
For complete darkness, either the guide rail or the end piece would probably have had to be notched out.
Regardless of light tightness, it is important to check whether the end pieces are rainproof. If not, a second water management layer must be created under the window sill.
You would probably have had to specify complete light tightness to have a claim to it.

According to it, both options are permissible.
For complete darkness, either the guide rail or the end piece would probably have had to be notched out.
Regardless of light tightness, it is important to check whether the end pieces are rainproof. If not, a second water management layer must be created under the window sill.
You would probably have had to specify complete light tightness to have a claim to it.
I just checked again and also closed the roller blind. For us, it is the same as expected. However, since the gap between the shutter and the window is significantly smaller in our case, the light leakage is naturally much less.
Additionally, our windowsill connection strip is a U-shaped profile on the side. Yours looks more like an L-shaped one.
Additionally, our windowsill connection strip is a U-shaped profile on the side. Yours looks more like an L-shaped one.
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