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Terminology and Assumptions　— How Terms Are Used on This Site

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This page clarifies how terms and concepts are used on this site,
with particular attention to points that are prone to misunderstanding.

Terminology related to rooftop greening is often interpreted differently depending on role or field.
To make discussions clearer, this site explicitly defines the underlying assumptions in advance.

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■ On the Term “Failure”

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On this site, the term “failure” does not simply mean that plants have died.

It also includes conditions in which the objectives of rooftop greening have not been achieved, such as:

・Greenery does not spread
・Ground coverage does not increase
・Maintenance cannot be sustained, resulting in eventual neglect

All of these are considered forms of “failure” in this context.

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■ On the Expressions “Viable” / “Not Viable”

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The term “viable” refers to a state in which a system can be maintained without excessive strain,
not only immediately after installation, but also over time.

Conversely, “not viable” refers to structurally unstable conditions, such as:

・Situations that assume heavy dependence on labor or equipment
・Problems that surface gradually as time passes

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■ On the Term “Structure”

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On this site, “structure” does not refer only to product form or construction methods.

It refers to the combination of underlying assumptions made during planning and design, including:

・How the rooftop environment is understood
・The premises on which plants are selected
・The extent to which maintenance and renewal are anticipated

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■ On the Term “Judgment”

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Here, “judgment” does not mean decisions based solely on individual experience or intuition.

It refers to the accumulation of choices—how multiple conditions are interpreted
and which assumptions are prioritized.

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■ On “Management” and “Maintenance”

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Management and maintenance are important elements of rooftop greening.

However, this site distinguishes between a state that functions only because management is constantly applied,
and a state that does not collapse significantly even with minimal intervention.

Whether a system is structured to avoid heavy reliance on maintenance
is considered a key factor in long-term stability.

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■ On “Warranties” and “Inspections”

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Warranties and inspections are often discussed as sources of reassurance.

On this site, they are not regarded as proof of viability for rooftop greening.

Instead, they are understood as frameworks that define how issues will be addressed after problems occur.

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■ Position of This Page

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This glossary is not intended to present “correct answers.”

Its purpose is to share a common baseline of meaning,
so that the same terms are used consistently throughout this site.

If any wording feels unclear or inconsistent while reading,
we encourage you to return to this page as a reference.

For those who would like to organize their thinking further

・Understanding the Structure That Enables Sound Judgment▶
・Structures That Lead to Failure▶

These two pages help clarify the underlying ways of thinking that form the basis for sound decision-making.