防水工 防水工
What 防水工 do
An English description is being prepared. Japanese description:
建物において防水工事を必要とする部分は多く、一般に降雨水の建物への侵入経路や、生活及び産業等に必要な水を貯水したり、不要な水を排水したりする部分には必ず防水工事が必要である。
防水工は、防水層の種別あるいは工法の種別によって、それぞれ専門的な技量を必要とする。防水層の種別にはアスファルト系防水層、合成ゴム系防水層、塩化ビニル樹脂系防水層、酢酸ビニル樹脂系防水層、ウレタンゴム系防水層、アクリルゴム系防水層、ＦＲＰ系防水層、セメント系防水に分けられ、工法も複数の種類がある。
防水層の種別あるいは工法の種別が増え、複数の防水層あるいは防水工法を施工できる技量が必要となっている。
◇ よく使う道具、機材、情報技術等
工具（かなづち、のこぎり等の手動工具、ドリル等の電動工具）、作業中の保護具（ヘルメット、ゴーグル、グローブ、安全靴等）
Employment type of workers
防水工 salary
The average annual pay for 防水工 in Japan is ¥4.67M (≈ $29,690; Basic Survey on Wage Structure (2025), national). The estimated median is ¥4.34M, the typical range is ¥3.28M–¥7.79M and the top 10% earn about ¥6.75M.
How does your pay compare with people your age?
Your numbers are not sent or stored. The distribution is estimated from Japan's national wage statistics, including pay differences by age.
Pay by ageest.
Estimated from the average pay and average age (41.6) using the age-wage curve of the Basic Survey on Wage Structure.
Pay by experienceest.
Pay by employment typeest.
The average hourly wage of ¥2,161 is 1.8× Japan's national average minimum wage of ¥1,177 (fiscal 2026). Minimum wage by prefecture →
Japanese pay is shown in yen (¥5.57M = 5.57 million yen ≈ 557万円). Dollar figures use the current rate of 157.25 yen per dollar and are for reference only; purchasing power differs.
Pay over time
| Year | Average pay | Employment | Openings ratio |
|---|---|---|---|
| 2021 | ¥4.32M | — | — |
| 2022 | ¥4.61M | — | — |
| 2023 | ¥4.53M | — | 4.82x |
| 2024 | ¥4.53M | — | 4.59x |
| 2025 | ¥4.67M | — | 4.37x |
Projected pay for 防水工 (3, 5 and 10 years)est.
Today ¥4.67M → in 3 years ¥5.16M → in 5 years ¥5.52M → in 10 years ¥6.53M (10-year range ¥5.61M–¥7.58M). The model assumes pay growth of +3.4% per year.
What drives the annual growth rate
Projected pay = current pay × (1 + annual growth)^years. The annual growth rate starts from a base wage-growth rate and adds or subtracts labor demand (the job-openings-to-applicants ratio), wage momentum and AI replacement risk for each occupation. Projections are not guarantees. How it is calculated →
Outlook score for 防水工
Each component is a percentile rank among all occupations in the same country (0–100). Weights: labor demand 25, wage momentum / openings 15, pay level 15, AI resistance 25, aging workforce 10 (Japan only), entry barrier 10.
Will AI replace 防水工? AI replacement risk
How AI is changing this job
A written analysis for this occupation is being prepared.
AI replacement risk compares the parts of a job that are easy to hand to AI or software (processing information, documentation, repetitive computer work) with the parts that are hard to automate (physical work, working closely with people, judgment in unpredictable settings), using the MHLW job tag survey on work activities, work context, skills and knowledge. The result is a relative position among all occupations in the country, scaled to 0–100%. Methodology →
Labor demand for 防水工
A ratio above 1.0 means there are more job openings than applicants (a labor shortage). The 5- and 10-year figures are estimates from the openings ratio, wage momentum and AI replacement risk.
The same job in the United States
| 防水工 Japan | Roofers United States | |
|---|---|---|
| Median / average pay | ¥4.67M ≈ $29,690 | $55,440 |
| Pay in 10 years (est.) | ¥6.53M | $77,400 |
| Outlook score | 63 | 65 |
| AI replacement risk | 18% Very low | 7% Very low |
| Workers | — | 135K |
Matched by occupation (SOC code). Yen converted at 157.25 JPY/USD for reference; Japanese figures are averages, U.S. figures are medians, and the surveys define occupations differently.
Skills, education and requirements for 防水工
Key skills
Skill levels from the MHLW job tag worker survey.
Key knowledge areas
What the work involves
Important abilities
Licenses and certifications (Japan)
- 有機溶剤作業主任者
- 危険物取扱者（甲種）
- 危険物取扱者（乙種）
- 危険物取扱者（丙種）
- １級防水施工技能士 National license
- ２級防水施工技能士 National license
Related qualifications listed on job tag (names in Japanese). Some are mandatory, others recommended.
Education of workers
Training before entry
Related work experience
Difficulty of entry: ★★★☆☆ Moderate (from education, training, experience, licenses)
How to become 防水工
The typical path in Japan is shown by the education, training and experience of current workers above and in the Japanese guidance below. A detailed English guide for this occupation is being prepared.
Guidance from job tag (Japanese)
入職後一定の実務経験を積んだ後に、厚生労働省の定める技能検定の「防水施工技能士」の資格を取得すると、技術の証明となる。
入職後に技能の向上を図り、更に経験を積むことによって、自営業者として独立、開業の可能性もある。
なお、防水工事の際にトルエンやキシレンなどの人体に有害な物質を含むウレタン溶剤などを用いることから、「危険物取扱者」、「有機溶剤作業主任者」などの資格を持っていることが望ましい。
Career path and how to earn more as 防水工
Career-path guidance is being prepared. Pay by experience is shown in the Pay section.