Purchasing · DIY · Komuten

DIY vs. Hiring a Komuten: What You Can Renovate Yourself in Japan

Author: AkiyaHub Team
Published: September 11, 2026

Contents

You do not need to know how to renovate everything before you buy

You can paint your own walls. You should not assume you can rewire your own house.

Imagine buying an older home in Japan with faded wallpaper, a cramped kitchen, and a few rooms you are eager to open up. At first, the work may sound manageable: strip the walls, replace the flooring, move a partition, update the lights.

Then you remove a panel and find old wiring. Or you lift a floor and find water damage. Or the wall you planned to remove turns out to carry more than paint and plaster.

That is the practical reality of renovating an older Japanese home. Many jobs are realistic DIY projects. Painting, wallpapering, shelving, furniture assembly, and some finish work can be satisfying ways to make an akiya feel like your own. But old homes often hide problems behind walls, under floors, and inside systems that have been altered over decades.

The useful dividing line is: are you changing the appearance of the house, or are you changing something that affects its structure, utilities, safety, or legal status?

That distinction should guide your renovation plan, budget, and decision about when to bring in a qualified local professional.

Before you begin

What this guide will help you decide

Before you buy an akiya with renovation plans, you need a rough division between work you may be able to handle yourself and work that needs a qualified local professional.

Use this guide to plan the work

1 Identify cosmetic and interior projects that may be realistic DIY work.
2 Understand why electrical, gas, plumbing, drainage, structural changes, and demolition need more careful checks.
3 Recognize when a renovation may involve permits, building-confirmation procedures, surveys, or specialist handling.
4 Learn what a komuten does and when it makes sense to hire one.
5 Ask better questions before committing to a property or opening up walls.

The goal is to help you tell the difference between a manageable DIY project and a renovation that needs professional assessment, a larger budget, or both.

Here is the short version before we look at the details.

Quick answer

The short answer

DIY is often suitable for cosmetic work and straightforward interior projects. More care is needed once the work affects systems behind the walls, the structure of the building, or its legal status.

Pause and check before starting

✓ Electrical wiring or panels
✓ Gas equipment or gas lines
✓ Water supply, drainage, or septic systems
✓ Load-bearing walls, floors, roofs, or foundations
✓ Major demolition or materials that may require special handling, including asbestos
✓ Work that may trigger building-confirmation or local approval procedures

The exact rules depend on the property, the scope of work, and the local authority. Before changing a system behind the walls or the structure of the building, confirm what applies to your house.

Start with the work that is visible, contained, and easier to correct if you make a mistake.

DIY starting point

Start with work you can realistically do yourself

Akiya ownership does not mean handing every task to a contractor. Many owners take on painting, wallpapering, flooring, demolition, and interior finishing themselves.

Hands-on work is part of the appeal for many buyers. Capability matters more than enthusiasm. A project is a good DIY candidate when you understand the work, can do it safely, and can correct a mistake without creating a larger problem.

DIY work that may be reasonable

✓Painting and wallpapering
✓Furniture assembly and built-in storage that does not affect the structure
✓Cosmetic repairs to interior finishes
✓Some flooring and tiling work
✓Garden cleanup and light landscaping
✓Cleaning, stripping, and refinishing non-structural surfaces

A job can look cosmetic until removing a surface reveals damaged framing, unsafe wiring, water damage, or a material that needs specialist handling.

The risk changes once a project reaches beyond finishes and into the house itself.

Know the scope

The line changes when the house itself is involved

Small jobs can become larger ones quickly in an old home. The more a project affects the building's structure or its utility systems, the more important it is to stop and check what is involved.

Separate the visible job from the system behind it

01Replacing a faucet is different from altering the water-supply system.
02Painting a wall is different from removing it.
03Replacing a light fixture is different from changing the wiring behind it.

Previous owners may have repaired, extended, or altered the house over many years. Once you open a wall or lift a floor, you may find old wiring, termite damage, water damage, improvised plumbing, or structural work that was never obvious from the finished room.

Electrical work is one of the clearest examples of why experience alone is not enough.

Safety and qualifications

Electrical work is a useful hard line

Japan has its own electrical-work qualification system. Electrical work covered by the relevant regulations generally requires a Japanese First- or Second-Class Electrician qualification, with exceptions for certain minor work.

Treat electrical condition as due diligence

Being comfortable with electrical work is not the same as being permitted to do all electrical work in a Japanese home. This applies even if you are qualified in another country.

✓Confirm the scope with a properly qualified professional before changing wiring, circuits, panels, or other regulated components.
✓Include potential electrical updates in the renovation budget before treating a low purchase price as a bargain.

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That does not mean practical experience from another country has no value. It means the work still needs to be understood in its Japanese context.

Bring experience carefully

Professional experience still matters, but assumptions can travel badly

An electrician, plumber, carpenter, or builder from another country may have deep practical knowledge. That knowledge matters, but it does not automatically transfer to Japanese rules, materials, or construction methods.

Check local practice before deciding

✓Do not assume a license, code, material, or normal construction method from home automatically applies in Japan.
✓Ask why before deciding that an unfamiliar detail is poor work.
✓Ask for a clear explanation when the answer affects safety, cost, durability, or your intended use of the home.

Bring your expertise with you. Bring your assumptions more carefully.

The same principle applies to water, drainage, and gas. The visible fixture is only one part of the system.

Systems behind the walls

Plumbing and gas need their own checks

Plumbing is not a simple choice between DIY and professional work. Certain water-supply and drainage work uses designated-contractor systems, while minor work may be treated differently.

Define the job precisely

01Are you replacing a visible fixture, or changing the system behind it?
02Are you fixing a surface problem, or altering a line, connection, drain, or appliance installation?
03Does the work affect gas, water supply, drainage, septic equipment, or buried lines?

Gas needs particular caution. If the project affects these systems, ask a qualified local professional what rules, permits, inspections, and contractor requirements apply to that specific job.

Structural changes deserve an even more careful pause because a wall or floor can do more than its finished surface suggests.

Structural changes

Do not remove walls without checking what they do

You cannot reliably identify a wall's role by looking at it. It may be a simple partition, or it may support part of the building, contain bracing, or carry wiring and plumbing that need to be rerouted safely.

Check before changing the layout

Japan's building rules changed in April 2025. Some substantial renovations to certain buildings, including many two-story wooden houses, may now require building-confirmation procedures. The details depend on the building and the planned work.

✓ Confirm substantial changes to walls, floors, roofs, or other structural elements with an architect, builder, or other qualified local professional.
✓ Ask whether the project affects structural safety and whether building-confirmation or local procedures apply.

Demolition often turns an assumption about the house into a fact. It is also the point where hidden defects and specialist handling can become impossible to ignore.

Before demolition

Do not start demolition before you know what is there

Demolition creates one of the largest gaps between a renovation plan and renovation reality. Opening up an older home can reveal hidden damage, outdated systems, or materials that need special handling.

Asbestos is one example. Japan requires asbestos investigations before certain demolition, alteration, and repair work, and people carrying out building investigations are subject to qualification requirements.

Use this sequence

01Define the work.
02Check the property's known history and condition.
03Ask whether a survey, inspection, notification, or qualified contractor is required.
04Budget for the findings before committing to demolition.

Once the work involves several trades, the next question is who will coordinate it and take responsibility for the moving parts.

Hiring local help

What a komuten does

A komuten (工務店) is generally a local building and renovation company. For a project involving several trades, a good komuten can organize the work and keep different parts of the project moving in the right order.

Some komuten perform work with their own staff. Others coordinate specialists such as carpenters, electricians, plumbers, gas technicians, roofers, and demolition contractors. A small, clearly defined job may be better handled directly by the appropriate specialist.

Ask who is responsible

□What work will your team perform directly?
□Which parts will be subcontracted?
□Who will handle electrical, gas, plumbing, and structural work?
□Who is responsible for permits, confirmations, inspections, or required notices?
□What happens if demolition reveals an unexpected problem?

A practical way to divide DIY and professional work

DIY does not mean doing everything yourself.

A sensible akiya renovation might look like this:

Work area	Typical approach	Expertise to involve	If the work goes wrong
Painting, wallpaper, cleaning, furniture, and cosmetic finishes	DIY if you have the skills and the work is genuinely non-structural	Homeowner or experienced DIYer	Uneven finishes, wasted materials, or work that needs to be redone
Shelving, storage, and small interior improvements	DIY after confirming you are not cutting into regulated systems or structural elements	Experienced DIYer; ask before cutting into walls, floors, or ceilings	Hidden wiring, plumbing damage, or damage to finishes and framing
Electrical wiring, circuits, panels, and system changes	Use a qualified professional and confirm the applicable requirements	Properly qualified electrician in Japan	Shock, fire risk, failed equipment, or work that does not meet applicable requirements
Gas appliances, gas lines, and related modifications	Use an appropriately qualified professional	Qualified gas professional	Gas leaks, fire, carbon monoxide risk, or unsafe appliance operation
Water supply, drainage, septic systems, and major plumbing changes	Confirm local requirements and use the right specialist where needed	Designated or otherwise appropriate local plumbing and drainage contractor	Leaks, sewage backups, water damage, or problems with local requirements
Walls, roofs, floors, framing, and foundations	Get a professional assessment before work begins	Architect, builder, carpenter, or structural professional, depending on the work	Structural damage, water intrusion, reduced durability, or approval issues
Demolition in an older property	Check for required surveys and specialist handling before starting	Qualified investigator and demolition contractor where required	Exposure to hazardous materials, hidden damage, unsafe work conditions, or unplanned disposal costs

The cheapest approach is rarely "do everything yourself." It is doing the work you can do well, then paying for the right help where a mistake would be expensive, unsafe, or difficult to reverse.

Use the questions below as a final pass before you decide whether a property is a manageable project for you.

Final pre-purchase check

Questions to ask before you buy

You will not have every answer before you buy. The point is to identify the questions that could materially change the cost, timeline, or practicality of the project before you commit.

Work through this checklist

□Which parts of the work can I realistically complete myself?
□Which jobs need a qualified Japanese professional?
□What needs to be repaired before the home is safe, weatherproof, and usable?
□Are there known electrical, gas, water-supply, drainage, septic, roof, or foundation problems?
□Has the house been renovated, extended, or altered before?
□Could the current layout hide structural changes, water damage, termite damage, or unsafe systems?
□Will planned demolition, alteration, or repair work require an asbestos investigation?
□Could my renovation affect structural elements or trigger building-confirmation procedures?
□Is there enough access for contractors, equipment, deliveries, and waste removal?
□What work needs to happen first, and what can wait until after I begin using the home?
□What is my budget for immediate repairs, professional surveys, permits or notices, materials, and contingency?
□If I will manage the property from overseas, who will coordinate inspections, contractors, deliveries, and unexpected problems?
□If I hire a komuten, what will it do directly and what will it subcontract?
□Who will confirm the permits, notices, inspections, and local requirements for this project?

You do need a realistic plan for the work

Start by separating the projects you can handle confidently from the work that needs a qualified local professional. Then look beyond the listing price. A home that seems affordable may still need electrical updates, plumbing repairs, structural work, drainage improvements, or specialist surveys before it is safe and comfortable to use.

If you are serious about a property, try to answer three questions before you commit:

What needs to be done immediately to make the home safe and usable?
Which parts of that work can I realistically do myself?
What professional checks, approvals, or contractor costs need to be included in the budget?

You will not have every answer before you buy. Older homes always carry some uncertainty. But the more clearly you divide cosmetic work from structural and regulated work, the better you can judge whether a property is a satisfying hands-on project or a renovation that needs more money, time, and local support than its price first suggests.

A good DIY plan does not begin with a demolition tool. It begins with a realistic view of the house, the work, and the help you will need.

This is exactly the kind of issue AkiyaHub helps buyers identify before they spend serious money. Where renovation work needs a closer look, we can also connect buyers with renovation specialist partners whose work we have seen and trusted on past projects.

Sources used for this article

Ministry of Economy, Trade and Industry (METI): Electrical Work and Electrician Qualifications - 電気工事士等資格制度 (text in Japanese)
Ministry of Land, Infrastructure, Transport and Tourism (MLIT): Building Confirmation and Inspection Changes - 建築確認・検査の対象となる建築物の規模等の見直し (text in Japanese)
- Designated Contractors for Water Supply and Drainage Work - 排水設備工事の指定工事店制度・指定給水装置工事事業者制度 (text in Japanese)
- Recognition of Foreign Construction Experience and Qualifications - 建設業に関する外国での経験等を有する者の認定について（大臣認定） (text in Japanese)
Ministry of the Environment: Asbestos Investigations Before Demolition and Renovation - 建物を壊すときにはどうしたら良いの？ (text in Japanese)

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