Global supply chain disruptions had a much-larger impact on PPG Industries' third-quarter sales than initially expected partly because key customers can hardly provide the company with their own accurate projections, CEO Michael McGarry told CNBC on Wednesday.

"Normally, for our automotive customers, when they give us a 90-day forecast, they're about 90% right. When they're at 60 days out, they're at like 95%, almost 98%," McGarry said in an interview on "Mad Money." "They haven't even been able to give us forecasts for a week or two, so they've been off a lot. They're not the only ones. We see the same thing in the appliance segment."

PPG, which makes paints, coatings and other specialty materials, entered the third quarter expecting a roughly $150 million dent to sales as a result of supply chain issues and customer production challenges, McGarry said last week on the company's earnings call. The actual impact ended up being more than $350 million, he said.

The complications are not just with auto and appliance customers, McGarry told "Mad Money" host Jim Cramer. He said PPG's suppliers are running into hurdles, too.

"We see that in a number of our other in-use segments, especially think about traffic paint. I mean, we're out there trying to paint roads but don't have the paint, and so that's been a challenge for us," McGarry said. "Our suppliers, which are major suppliers, they're having troubles getting their factories back in the kind of shape it was back in 2019" before the coronavirus pandemic hit.

Despite the current woes, McGarry said he has a favorable outlook for next year due, in part, to his belief that commodity costs will start to stabilize.

"Raw materials are going to start to flatten out. That's going to be good for us because we're getting a lot of price," the chief executive said. "But more importantly, we have a strong order book so when I look at demand whether it's cars, whether it's planes, there's going to be a lot of latent demand that we're going to see in 2022 that we haven't been able to fill in 2021 because of raw materials shortages."