When We Tried to Save on Trim Spacing (And What It Cost Us on a 12-Home Development)

The Day We Misjudged the Spacing

It was a Tuesday morning in Q1 2024, and I was walking the site of a 12-home development. Framing was up, and the trim crews were scheduled to start installing the Fypon dentil molding on the porch gables. Fine, I thought. Standard trim job.

But something looked off.

I stopped at the first house. The gable bracket was mounted fine. The window header looked clean. But the dentil molding across the front edge—the spacing between the blocks wasn't consistent. Instead of a steady, rhythmic pattern, there were gaps where the blocks were bunched up, and then a wider space that played tricks on your eye.

“Looks okay from the street,” the site supervisor said. “Nobody's gonna measure it.”

He wasn't wrong about that. But I'd been doing quality reviews for over four years, and my gut said this was the kind of thing that turns an $875,000 home into something that feels cheap.

The Assumption We Made

Here's where the mistake happened.

The general contractor had ordered Fypon Siding Grafton for the body of the houses and Fypon dentil molding for the gables. All standard catalog pieces. The drawing showed a run of dentil molding across the front of the gable, but it didn't specify the spacing in eighth-inches between blocks—just that it should be “even.” The crew assumed they knew what even meant. So did we.

Wrong assumption.

They started at the center of the gable and worked outward, which is standard practice for symmetry. But the gable width was exactly 24 feet—a dimension that doesn't divide evenly by the block width plus a typical 1/8-inch gap. When the last block at each end didn't line up with the trim edge, they fudged the spacing on the last three feet to make it fit.

I assumed the math had been checked. Didn't verify. Turned out nobody on site had calculated the exact number of blocks needed for that run and what the spacing threshold would be.

The Cost of That Assumption

We flagged the issue on our inspection report. The builder's finish carpenter argued it was acceptable “within industry tolerance.” But I'd just come from reviewing a similar job that used precut stone veneer headers—beautifully consistent—and the contrast between that tight, measured look and the fudged dentil spacing was night and day.

We rejected the work.

Here's the math. They had to pull off all the dentil molding from 12 gables. Some pieces could be salvaged, but PVC trim—especially interlocking or finger-jointed pieces—doesn't always come off clean. Replacement stock cost us about $2,800. Labor to re-install with proper spacing, another $1,600. And the delay pushed back the painting schedule by three days, which cost the builder $2,400 in carrying costs on the construction loan.

Total waste: $6,800.

All to save maybe $80 on an extra few feet of molding that would have made the spacing work perfectly.

How We Fixed It

After that fiasco, I implemented a simple verification protocol. Now every order for Fypon trim—dentil molding, headers, porch posts, balustrade sections—includes a layout calculation before installation starts.

It's dead simple:

• Measure the exact run length (down to the 1/8 inch).
• Divide by the block or module width plus a target gap (usually 1/8 inch for dentil).
• See if it divides evenly. If not, adjust the gap in hundredths of an inch across the whole run.

Most installers can do this in about fifteen minutes with a calculator and a piece of paper. Fifteen minutes per gable. We have twelve gables. That's three hours of pre-work that would have saved us $6,800.

“I assumed 'same specifications' meant identical results across vendors. Didn't verify. Turned out each had slightly different interpretations.”

Same principle here. The Fypon product itself was fine—consistent density, sharp detail on the molding profile. The error was entirely in installation planning.

The Honest Story About Limitation

I'll be honest: Fypon's PVC trim products work great for this kind of application. The material doesn't rot, it takes paint well, and the detail on the dentil molding is crisp enough that you can't tell it from primed wood from six feet away. That's why we spec'd it for this development.

But no product is idiot-proof. The limitation isn't the material—it's the assumption that standard dimensions will magically fit every run. If your crew isn't paying attention to layout math, even the best PVC trim won't save you from inconsistency.

The product is good. The planning has to be better. We learned that the hard way.

What We Changed Going Forward

Since that project, every spec sheet I write includes a line item: “Verify layout spacing before installation of all decorative trim.” It sounds obvious in hindsight. But in a hurry-up world where the framing happens on Monday and the trim crew shows up on Tuesday, math gets skipped.

We also started ordering an extra 10% of any trim piece that requires precise spacing—dentil molding, balustrade spindles, porch pickets. That's not a Fypon recommendation; it's just practical risk management. The extra cost is trivial compared to the cost of rework.

If you're specifying Fypon for a project—and honestly, for 80% of exterior architectural trim applications, I'd recommend it—take the extra fifteen minutes to do the layout math. I know that sounds like a boilerplate suggestion. But after watching a $6,800 mistake unfold because nobody wanted to stop and divide some numbers, I can tell you it's not boilerplate. It's the difference between gables that look sharp and gables that look… fudged.

We haven't had a rejected dentil run since. Simple fix, once you know the problem.