Architect Reveals: The Truth About "Contracts and Warranties" That Interior Contractors Never Tell You—How to Avoid Regrets After Construction
Introduction
Following "estimates" and "construction schedules," another thing often overlooked before opening a business is the "contract" and "warranty."
Just because construction is finished and the shop is open doesn't mean you can rest easy. When defects appear after opening, the extent to which the contractor will handle them is determined by the contract signed before construction began.
Many people decide on a contract based solely on the amount in the estimate. However, the content of the contract is just as important as the price.
From my perspective of having watched this industry for 15 years, I will share the points that are often overlooked regarding contracts and warranties.
Part 1: "Verbal promises" are almost legally meaningless
"It's fine, we'll take care of that properly."
Verbal promises on-site are a common sight. However, anything not written in the contract will turn into a "he-said, she-said" argument later.
Especially dangerous are verbal promises regarding additional work or specification changes. It is not rare for things said to be "done as a service" to be billed later.
Correct approach
Do not let on-site agreements end there; always confirm them in a form that leaves a written record, such as email or LINE. Sending a single sentence like, "Regarding the matter we discussed earlier, is it correct that there will be no additional costs?" serves as evidence.
Part 2: Warranty periods differ for each type of construction work
Do you believe the explanation "we provide a 1-year warranty" just as it is?
In fact, it is common for the warranty period to differ depending on the part of the construction.
General guidelines (vary by contractor and contract)
Interior finishing (wallpaper, painting, etc.): about 1 year
Waterproofing work: about 5 to 10 years
Structural work: about 10 years
Equipment (manufacturer warranty): about 1 to 2 years (depending on the manufacturer)
If you feel reassured by just hearing "1-year warranty," it is possible that parts that should have had longer warranties, such as waterproofing or structural elements, are actually being cut off after one year.
Correct approach
Do not group everything under a single 'warranty'; ask for the warranty period for each construction item to be clearly stated in writing. It is especially worth checking waterproofing, structure, and equipment individually.
No. 3: Confirm the conditions that exclude coverage from the 'warranty'
Warranty documents sometimes contain fine print stating conditions that are 'excluded from warranty coverage'.
Common conditions excluded from warranty
Damage caused by natural disasters (earthquakes, typhoons, etc.)
Scope considered as normal wear and tear
Defects caused by the customer's method of use
Areas where other contractors have performed work
The problem is that the line between 'normal wear and tear' is ambiguous. When a defect appears after three years, the conclusion can change based solely on the contractor's judgment as to whether it was poor workmanship or normal wear and tear.
Correct approach
Before signing the contract, confirm 'What are the criteria for considering something normal wear and tear?' and 'Is there a way to consult a third party if I am not satisfied with the judgment?'
No. 4: Confirm the 'after-sales support contact point'
Being unable to contact the person in charge after construction is finished—this is something that actually happens.
Especially in companies that use many subcontractors, the responsibility can become ambiguous with excuses like, '**The person in charge has quit**' or '**The craftsman who handled that work is no longer here**'.
Correct approach
When signing the contract, confirm, 'Is the after-sales support contact point an individual person or the company itself?' Always make sure to keep a record of the company's contact information, not just the individual's contact details.
No. 5: Five items that must be included in the contract
Based on the points covered so far, here is a summary of the minimum items that should be included in the contract.
✅ Details of construction work (Are specifications and drawings attached?)
✅ Amount and Payment Terms (Percentage and timing of down payment, progress payment, and final payment)
✅ Construction Schedule (Start date, estimated completion date, and response to delays)
✅ Warranty Details (Warranty period for each construction item and conditions for exclusion)
✅ After-Sales Support Contact (Company contact information)
If you are proceeding with a contract while these points remain vague or are only explained verbally, please stop and request that they be clearly stated in writing.
How to Deal with Contractors Who Won't Sign a Contract
Rarely, there are contractors who try to proceed with only verbal agreements, claiming that "contracts are just a formality."
This is a clear red flag. Reliable contractors will properly prepare a contract and take the time for both parties to review the contents.
If a contractor is reluctant to prepare a contract or tries to skip explaining its contents, you should consider declining the contract.
Conclusion
Estimates, construction schedules, contracts, and warranties—what all these points I have discussed have in common is the need to request written documentation rather than relying on "verbal explanations."
Trusting a contractor and verifying the contract details are not mutually exclusive. In fact, when clients do not neglect to verify details, contractors are forced to respond more sincerely.
Your shop is something you will continue to use for many years after the construction is finished. Please do not forget that the few dozen minutes you spend verifying details before construction begins are what protect that peace of mind.
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I have been running a construction company for 15 years, staffed by many qualified professionals including architects, electrical engineers, and plumbing construction management engineers. We have a proven track record in constructing restaurants, clinics, hair salons, professional offices, beauty salons, and more. I am currently sharing information on store and facility interior design from a field-based perspective.
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