The house where a 500,000 yen lattice ends up as 'just a decoration' vs. the house where you can throw away all your curtains. The difference is just a '90-degree' decision.
Here is one shocking fact.
Just by getting the orientation of the lattice wrong by 90 degrees, 500,000 yen goes to waste.
'I installed a lattice for privacy, but the inside of the room was completely visible from the outside.'
—This failure is no laughing matter.
I have actually seen it many times.
They spent hundreds of thousands of yen to install a beautiful lattice, yet they end up keeping the curtains closed anyway.
The lattice is meaningless. The money has vanished.
But conversely, a house that chooses the correct lattice orientation can remove all its curtains.
The morning sun enters just as it is.
It cannot be seen from the outside even at night.
The breeze passes through. The light passes through.
And it is beautiful as a design as well.
What creates this difference is not the material, the color, or the designer's sense.
Whether to make the lattice vertical or horizontal—it is just a 90-degree decision.
And there is a clear scientific basis for this decision.
It is the principle of ergonomics regarding how human eyes move.
The line of sight of a person walking, a person looking up, a person sitting—
—you align the orientation of the lattice to each of those movements.
Just by doing that, 'visible' changes to 'invisible'.
For those considering a lattice for their exterior or louvers for their balcony.
Please do not decide on the orientation before reading this article.
500,000 yen is too expensive for a 90-degree judgment error.
Low-position lattices should be 'vertical'—the principle of blocking the gaze of passersby
First, let's talk about exterior lattices around the first floor.
When someone walking on the road looks into a house, their gaze moves horizontally.
They turn their head sideways while walking and glance over.
At this time, if the lattices are arranged vertically, every time the pedestrian's gaze crosses a lattice, the line of sight is repeatedly blocked and opened.
The eyes cannot keep up, and the image of the interior does not come together. In other words, it is hard to see inside.
Conversely, what happens if the lattices are arranged horizontally?
Even if the pedestrian moves sideways, the gaps in the horizontal lattice remain open at the same angle.
Whether they walk or stop, the view through the gaps does not change. In other words, it is fully visible.
This is the principle behind 'make low-position lattices vertical'.
Ergonomically, a lattice in the same direction as the moving gaze cannot block that gaze.
In this house as well, the wooden lattice around the entrance is arranged vertically.
It blocks the view from the road while allowing wind and light to pass through.
The light entering through the gaps in the lattice creates striped patterns on the floor, which also serve as a beautiful accent of light and shadow during the day.
High-position lattices should be 'horizontal'—the principle of blocking the upward gaze
Next, let's talk about second-floor balconies or upper-floor lattices.
When someone on the ground looks up at a balcony, their gaze moves from bottom to top.
At this time, if the lattices are arranged horizontally, the upward gaze is blocked by the horizontal lattice boards, making it impossible to see inside.
The horizontal slats overlap like 'eaves,' blocking the line of sight from below.
On the other hand, what about the people inside the room?
Whether sitting or standing, the eye level is almost horizontal.
Since the gaps in the horizontal lattice open horizontally, the view outside is clearly visible from inside the room.
In other words, horizontal lattices allow for one-way line-of-sight control, where people looking up from below cannot see inside, but people inside can see outside.
What happens if you use a vertical lattice on a balcony?
The upward-looking line of sight passes through the vertical gaps, making the inside of the balcony visible.
Especially at night, an illuminated room is clearly visible through the gaps in the vertical lattice.
To summarize—
Low position (1st floor/exterior) = vertical lattice.
Blocks the horizontal movement of pedestrians' lines of sight.
High position (balcony/2nd floor) = horizontal lattice.
Blocks the upward-looking line of sight while allowing a view of the outside from within the room.
If you install a lattice without knowing this rule, you will end up with the worst possible result: having spent money only to still need curtains.
Color design for an 'attractive lattice exterior' read through Munsell values
From here, I will break down the colors of the entire exterior of this house.
Light gray (exterior walls, approx. 55-65% of the total): N7-N8
N stands for neutral (achromatic), and a lightness of 7-8 is a 'bright gray close to white.'
The large volume of the upper floor is covered in this color.
There are two reasons for choosing N7-N8 instead of pure white (N10).
One is that dirt is less noticeable.
Pure white shows rain streaks and moss over time, but with light gray, the color difference between the dirt and the wall is small, allowing it to look clean for a long time.
The second is that the shadows appear soft.
Pure white reflects sunlight strongly, making shadows harsh, but light gray receives light gently, creating beautiful gradations of shadow.
Wood parts (lattice, eaves soffit, front door, approx. 12-20% of the total): 7.5YR 6/4
7.5YR is a yellow-red tone, lightness 6 is on the brighter side, and saturation 4 is a modest level that brings out the warmth of the wood.
It is a bright wood color like cedar or oak.
What is important here is that the lattice is a 'translucent' material.
Using wood as a surface like a board wall can feel heavy, but by using a lattice, you can retain the warmth of the wood while suppressing a sense of oppression.
Furthermore, because the lattice lets light through, patterns of shadow fall on the wall surface, enriching the space as 'moving patterns' during the day.
It is also important that the wood color has low saturation (7.5YR 6/4).
If the wood is a vivid orange color with a saturation of 6 or higher, the contrast with the gray exterior wall will be too strong, resulting in a state where 'only the wood stands out'.
With modest wood at saturation 4, warmth subtly resides within the tranquility of the gray.
White to off-white (frame, bargeboard, approx. 10-15% of the total): N9 to N9.5
A nearly white frame.
By bordering the perimeter of the building with a white line, a frame effect is created.
The light gray surface is contained within the white frame, appearing complete as 'a single painting'.
Dark gray to black (shadows, openings, metal fittings, approx. 5-10% of the total): N3 to N4
Dark tones exist only in the depths of openings and shadows, limited to 'lines and points' rather than 'surfaces'.
Because black is not used as a surface, the building does not look dark.
To summarize, gray (surface of tranquility) 60%, wood (line of warmth) 15%, white (frame) 12%, black (outline) 8%.
This ratio creates an exterior that is 'elegant without being overly assertive'.
'Quiet above, warm below'—the two-layer structure created by the placement of the lattice
The most effective aspect of this house's exterior is separating the character of the upper and lower floors.
The upper floor keeps openings to a minimum, pulling everything together quietly as a large gray surface.
There are few windows and the walls are expansive.
This 'quietness of negative space' creates the dignity of the entire building.
The lower floor features wooden lattices, wooden eaves, and a wooden front door
—concentrating warm-colored materials at a scale that people can touch.
Furthermore, the eaves extend horizontally, giving the building a wide sense of stability.
Upper = quiet, lower = warm.
This two-layer structure aligns with human psychology.
The part near the sky is abstract and quiet, while the part near the ground is concrete and warm.
Church architecture and art museums are also designed based on this principle.
8 rules that make this space effective
1. Use vertical lattices for low positions.
This blocks the horizontal movement of pedestrians' gazes, creating privacy that makes curtains unnecessary.
2. Use horizontal lattices for high positions.
This blocks upward gazes while allowing a one-way view control where you can see outside horizontally from inside.
3. Use 3 colors + a white frame.
Gray (surface), wood (warmth), black (outline), white (frame). This composition achieves both elegance and quietness.
4. Choose a light gray (N7 to N8) for the exterior walls.
It is more resistant to dirt than pure white and creates softer shadows. A color that looks clean for a long time.
5. Use wood by 'filtering' it through a lattice.
Using it as a solid surface feels heavy. Using a lattice retains the warmth while suppressing the sense of oppression and also provides striped patterns of light.
6. Keep the saturation of the wood at 4 or less.
Vivid wood clashes with gray walls. A subtle warm color blends naturally into a quiet space.
7. Keep the upper floor quiet and the lower floor warm.
The part near the sky is a gray negative space, and the part near the ground is the warmth of wood. This two-layer structure creates dignity.
8. Create a sense of stability with the horizontal line of the eaves.
Long eaves draw the gaze horizontally, making the building look wide and solid.
Candidate materials you can actually use
1. For light gray exterior walls (plaster type):
Aica Kogyo 'Jolipad Alpha JP-100'.
With a matte plaster finish, you can beautifully express light gray in the N7 to N8 range.
→ https://www.aica.co.jp/
2. For light gray exterior walls (siding type):
Nichiha 'Moen Excerad 16'.
Highly maintainable with a wide variety of gray color options.
→ https://www.nichiha.co.jp/
3. For entrance doors (wood texture):
LIXIL 'Rechent Entrance Door 3' RC-S.
It is easy to match the color temperature with that of the wooden lattice.
→ https://www.lixil.co.jp/
4. For stone-style paving on the approach:
Toyo Kogyo 'Praga Stone' PS-S.
It organizes the footing of the exterior and extends the order of the building down to the ground.
→ https://www.toyo-kogyo.co.jp/
3 points to check
1. Check whether the location where you are planning the lattice is in a 'low position' or a 'high position'.
Vertical lattice if low, horizontal lattice if high.
This one decision changes whether or not you need curtains.
2. Once you have decided on the orientation of the lattice, perform a simulation where you actually 'walk and look'.
Together with your designer, check how the interior looks through the gaps in the lattice when walking from the road.
You cannot understand the movement of the line of sight from drawings alone.
3. Check if the color temperature of the lattice and the exterior wall match.
If the wooden lattice has too much red, it will look like it is floating against the gray exterior wall.
Line up samples and check them under natural outdoor light.
A lattice is 'design', 'function', and 'science'
Lattices and louvers are often chosen solely for their aesthetic beauty.
But, if you get the orientation wrong, it won't function.
You will end up needing curtains, and the purpose of the lattice will be lost.
Vertical for low positions. Horizontal for high positions.
—This rule is based on the scientific fact of how the human eye moves.
It is not a matter of design preference, but a principle of ergonomics.
Furthermore, a lattice lets in light, allows air to pass through, and creates shadows.
It protects your privacy while maintaining a sense of openness.
It is not a device for closing, but for “choosing what to open.”
By simply choosing the correct orientation for the lattice, you can achieve a life with windows that don't require curtains.
You can protect your privacy at night without blocking the morning light.
—This balance cannot be achieved without knowledge.
Is the lattice on your house oriented correctly?
Architectural Consultant Koike | Amigo Housing Seminar
With 27 years of experience and over 7,000 housing consultations, I provide the 'eye for quality' and the 'words to convey it'.
I also accept individual consultations via my official LINE account.
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