Why interior material prices keep going up — how it looks from where we work

We hear “another price rise?” more often than we used to.

Counting from 2022, interior material prices have moved so many times we have lost track. The news lists the weak yen, expensive oil, tensions in the Middle East — but from where we work, the order of importance looks different.

What follows is our own reading. Please take it as an interpretation of what we can see from site, not a forecast.

1. The biggest factor is the raw material itself

Line up the explanations for interior material price rises and the same words come up at every supplier: crude oil and naphtha.

Naphtha is the base feedstock of petrochemicals, refined from crude oil. PVC comes from it, so do the resins in adhesives, and paint. You could fairly say interior materials are almost entirely petrochemical products.

And naphtha rose sharply through 2026. According to Nikkei, the price of domestic naphtha for the April–June quarter hit a record high, roughly doubling on the Middle East crisis.

When the material behind the material doubles, a 20–30% rise in the finished product looks to us like restraint rather than excess.

2. Next comes “you cannot get it”

This is the part that gets overlooked.

Alongside the price announcements came a run of order suspensions and shipment limits. Adhesives, spacers, resin trims. In places, the situation is not “expensive but available” but “not available at all”.

When volumes fall, manufacturers cannot run their plants efficiently. Cost per unit goes up, and that goes into the price too. Price rises feeding price rises.

Seen from site, this hurts more than the price does. You can write a figure into an estimate; you cannot write in a material that will not arrive.

3. The weak yen is an amplifier

We see the weak yen less as a cause than as something that widens the swing.

As long as the raw material is bought in dollars, the same quantity takes more yen. Put a weak yen on top of naphtha doubling and the domestic procurement cost swells by more than the raw figure suggests.

Which also means it is the part that eases if the yen strengthens. It should come back faster than the raw material price does.

4. Labour and logistics do not come back down

There is one more factor working quietly.

Overtime limits for lorry drivers, working-practice reform in construction, rises in the minimum wage. All of these have come in by stages since 2024, and freight and labour costs are structurally higher as a result.

Raw materials trade on a market, so they can fall. Labour, once it has gone up, does not come down. That, we think, is the difference between this round and the rises from 2022.

So when does it settle?

Honestly: we do not know.

With that said, here is how we see it.

The raw-material part may come down if the Middle East and the oil market settle. But manufacturers’ price revisions never come down as quickly as they go up. Rises are immediate, reductions are gradual — that is how it has gone before.

The supply blockage should clear relatively quickly once the raw material flows again. In fact we have seen orders reopen about a month after being suspended (at the revised price, once reopened).

Labour and logistics costs we do not expect to return. That is better read as a change in the baseline.

So our reading is: prices will not go back to where they were, but we are near the ceiling. We may be wrong.

What we decided to do

In a period like this, a contractor can take one of two attitudes.

One is to quote high up front. You lose nothing if prices rise. But if they do not, the difference quietly becomes profit.

The other is to quote at the price on the day, and disclose it if it moves. It is more work, but the client can see what is happening.

We chose the second. We state the validity period of the estimate clearly, and where a job straddles a revision we reissue it with the reason attached. Not “materials went up” and nothing more — we tell you which manufacturer put what up, and by what percentage.

We cannot stop the price rises themselves. What we can do is make them price rises you can understand. That part is on our side of the table.

Sources

Written byOS Co., Ltd.This article was drafted by AI and checked by our staff before publishing.

OS Notes