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DIY Construction and Infrastructure

After completing partial demolition and addressing termite extermination and prevention, the next step is building the foundation. At this stage, you’ll also need to hire an infrastructure contractor. Once your renovation plan is set, find a contractor to handle the infrastructure work and request a quote.

In some countries, DIY projects involving infrastructure like electricity, gas, and water might be common, but in Japan, such work is typically prohibited for unqualified individuals. Here’s a quick overview of what DIY work is allowed and what requires professional qualifications in Japan.

Electrical Work

In Japan, wiring and other electrical work require a licensed electrician. Even replacing electrical outlets must be done by a qualified professional.

If you want to do DIY electrical work, you can obtain the 2nd Class Qualified Certified Electrician certification. This involves passing written and practical exams, and no prior work experience is needed. However, the exams are only available in Japanese, so a strong command of the language is essential. The exams are manageable with self-study materials like textbooks and instructional videos, but practice is key for passing the practical component.

Creating devices that plug into an outlet, such as homemade lights, is not considered electrical work, so you can use these yourself. However, selling such devices requires the PSE (Product Safety Electrical Appliance & Materials) mark. Selling devices without this certification is illegal. Low-power devices like those running on batteries or USB often don’t need a PSE mark.

It’s also illegal to secure extension cords to walls or floors using staples or nails, though many people in Japan are unaware of this rule. Temporary fixes with double-sided tape are acceptable, as they don’t damage the cords.

If you want to hide wiring inside walls or ceilings, hire an electrician to complete the wiring before finishing the walls. Afterward, outlets and switches can be installed.

Plumbing Work

DIY plumbing is limited to simple tasks like replacing gaskets, faucets, or insulating water pipes. More complex work, such as installing water and sewage pipes, requires a licensed plumber. These qualifications usually require work experience, making it difficult for amateurs to obtain them.

Beware of unscrupulous plumbing companies that overcharge. Avoid contractors with excessive advertising or door-to-door sales tactics. Instead, consult your municipality’s list of designated contractors, compare quotes and professionalism, and choose accordingly.

Plumbing work that involves running pipes under floors or behind walls is usually done before floors and walls are installed. While it’s possible to add plumbing afterward, it can be more challenging, costlier, and may prevent pipes from being hidden inside walls.

Gas Work

Gas-related DIY work is strictly prohibited in Japan. Connecting gas pipes requires a licensed technician, and unqualified individuals are not allowed to replace gas stoves or propane gas connections. Only portable gas cylinders are exempt from these rules.

You can buy gas appliances, such as stoves or water heaters, yourself and have a professional install them. Be aware that Japan uses two types of gas: propane and city gas. These have different properties and require compatible appliances, so check your gas type before purchasing.

Since gas pipes are often installed under floors or along exterior walls, it’s best to have this work done before floors are finished to ensure smooth progress.

Older Japanese homes often used insulators for wiring, but modern homes typically use vinyl-insulated flat cables. Insulator setups are rarely seen today.

Plumbing for water and gas is often done during the foundation phase when floor joists are installed. Care must be taken not to damage the plumbing when finishing floors and walls.

When wiring or plumbing under floors or in ceilings, ensure inspection openings are included for maintenance and final connections. For electrical work, it’s illegal to have branch or connection points in inaccessible areas.