Failures in rooftop greening occur not after construction, but before decisions are made.

Rooftop greening is an effective means of improving a building’s environmental performance and landscape value.
However, in real-world practice, cases like the following continue to occur:

• The condition deteriorates after several years
• Maintenance cannot be sustained and the area is eventually left unmanaged
• Unexpected repairs or removal become necessary

Many of these problems are not caused by post-construction maintenance failures or by the plants themselves, but by the fact that key assumptions were not properly examined before the system was selected.

This page provides a simple checklist designed to help you pause and reconsider your decisions before choosing a rooftop greening approach.

About This Checklist

This checklist is not intended to determine the superiority of any rooftop greening method or product.

• It is not for choosing a single “correct answer.”
• It is not for scoring or ranking options.

Its purpose is to help clarify:

• Why you are considering a particular choice, and
• Whether the assumptions behind that choice truly hold.

If there is even one item you find difficult to explain,
that is not a sign of failure—
it is an important clue pointing to what should be examined next.

10 Pre-Decision Checks (Quick Guide)

☐ Will the system deteriorate quickly if irrigation stops during periods of high heat or dryness?
☐ Can you explain what happens to water and soil during heavy rainfall?
☐ If weeds increase, is ongoing management still realistic?
☐ If maintenance is temporarily interrupted, will the situation become critical?
☐ If the contractor changes, will the outcome remain largely the same?
☐ Are you relying on the number of past projects alone for reassurance?
☐ Are you being influenced by advertising phrases such as “No.1” or “the best”?
☐ Are you choosing based only on catalogs or numerical specifications?
☐ Are you assuming long-term warranties alone ensure reliability?
☐ Have you considered how it will be handled several years later or during waterproofing renewal?

If even one of these items is difficult to explain clearly,
it is recommended to pause and examine the plan more carefully.

More detailed explanations and notes are summarized in a one-page A4 PDF.

Download the “10 Pre-Decision Checklist” (PDF)

This checklist is not a tool designed to lead you toward a specific choice.

It is a guide meant to help you pause before deciding too quickly.

Rooftop greening is a field where
environmental conditions, maintenance, construction, and long-term change all overlap.

For that reason,
clarifying the assumptions behind your decision is the most effective way to avoid major failures later on.

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.