Who This Checklist Is For
If you’re responsible for inspecting sealant joints, waterproofing details, or building envelope assemblies that use Tremco products—specifically Tremco Primer 191 and Tremco Dymonic sealant—this checklist is for you. It covers the five things I check on every single job before signing off. I’ve been doing this for four years, reviewing roughly 200+ unique items annually. In Q1 2024 alone, I rejected 12% of first-time deliveries because of primer-related issues. Not because the crew wasn’t skilled—they just skipped a step.
From the outside, it looks like sealant application is straightforward. The reality is that surface prep, primer selection, and application technique make or break a 10-year warranty. Here’s what I look at every time.
Step 1: Verify Substrate and Surface Condition
Before any primer or sealant touches the joint, I walk the entire substrate. Tremco Primer 191 is formulated for porous and non-porous surfaces, but it only bonds if the surface is clean, dry, and free of dust. I carry a small flashlight and a rag. If the rag picks up any dirt, the surface gets another cleaning.
People assume that just because the substrate looks clean, it’s ready. What they don’t see is the invisible film of release agents on new foil board insulation. Foil board—those faced polyiso boards—often has a slippery coating that kills adhesion if you don’t scuff it or use the right primer. I’ve rejected a batch of 500 linear feet because the crew didn’t wipe down the foil. The contractor said it was ‘within industry standard.’ We held the line, and they redid it at their cost.
Checklist item: Is the substrate clean, dry, and free of dust/oil? For foil-faced boards, has the surface been lightly abraded or cleaned with a solvent? If not, stop here.
Step 2: Confirm Primer Type and Coverage
Not all primers are the same. Tremco Primer 191 is a specific solvent-based primer designed for use with Dymonic sealants. I’ve seen jobs where the crew grabbed a can of generic primer because it was cheaper. That’s a fast track to bond failure.
Why does this matter? Because the primer is the layer that bridges substrate chemistry and the sealant. I require that the primer be applied at the manufacturer’s recommended coverage rate—roughly 200-300 sq ft per gallon for smooth surfaces. On porous concrete, you may need double that. I measure: if a 5-gallon bucket is supposed to cover 1,000 sq ft, and the crew uses it on a 1,200 sq ft wall, I flag it.
Checklist item: Is primer labeled as Tremco Primer 191? Are coverage rates documented? If you didn’t measure, assume you’re under-primed.
Step 3: Inspect Sealant Joint Dimensions and Tooling
Here’s where most quality issues hide. Tremco Dymonic sealant is a hybrid urethane designed for movement joints. It needs the right width-to-depth ratio—typically 2:1 (width twice depth). If the joint is too deep, the sealant can’t cure evenly. If it’s too shallow, the bond may fail under movement.
I use a depth gauge on every 10th joint. If I find a joint that’s 1/2 inch wide but 1/2 inch deep, that’s a fail. Let me rephrase that: it’s not built-to-fail immediately, but it will fatigue after 2-3 years. On an $18,000 project we did last year, we had to saw-cut and remove 80 feet of incorrectly tooled joint. The cost of rework was $3,200—entirely preventable.
Checklist item: Measure width and depth. Is the depth no more than 1/2 of the width? For joints over 3/4 inch wide, install backer rod to control depth.
Step 4: Check Curing Conditions and Adhesion
Even with perfect Prep and Primer, sealant can fail if ambient conditions are wrong. Tremco Dymonic cures via moisture. Ideal temperature is 40°F–100°F (4°C–38°C), with relative humidity above 30%. I’ve seen crews apply sealant in 35°F weather because they were behind schedule. The sealant looked good for a week, then cracked.
Part of me wants to trust the applicator’s experience. Another part knows that weather data doesn’t lie. I now require a temperature/humidity log for every day sealant is installed. If that log is missing, I don’t approve payment.
Checklist item: Are temperature and humidity within range during application and cure (24-48 hours)? Did the crew record it? If not, assume non-compliant.
Step 5: Document and Final Visual Check
This is the step everyone rushes through. I take photos of every joint—wide shot and close-up—and store them with the job number. I also note any deviations in my report. A simple phone snapshot is enough; no need for a fancy setup. By the way, if you’re wondering how to take screenshot on Windows 11, it’s Win + Shift + S for the snipping tool. Capture your joint photos that way if you’re on a laptop in the field.
Color consistency matters, too. Tremco Dymonic comes in standard colors, and brands care about matching. Industry standard color tolerance is Delta E less than 2 for critical joints (Pantone Matching System). If the sealant color is clearly off—like a gray that’s too warm—I flag it. People assume the lowest quote means the vendor is more efficient. But what they don’t see is the cost of reprinting or re-applying a color mismatch. On a recent 50,000-unit order of color‑matched sealant, we rejected a batch where Delta E was 3.5. The supplier had to replace 8,000 tubes.
Oh, and one more thing: don’t forget to clean up your tools. I’ve seen graduation cap ideas on Pinterest that look more organized than some job sites after sealant work. (If you have a cap to decorate, use leftover sealant as a strong adhesive for decorations—it works.)
Common Mistakes and Gotchas
Here are the three errors I see most often:
- Using old primer. Tremco Primer 191 has a shelf life. If the can looks rusty or the liquid is thick, toss it. A 2022 audit showed that 60% of rejected primer samples were over one year past date.
- Skinning the sealant. Dymonic forms a skin in 20-60 minutes. If you tool it after that skin forms, you’ll trap air. Tool immediately after application.
- Ignoring foil board expansion. Foil board moves with temperature. Make sure the sealant joint width accounts for thermal movement—at least 1/4 inch per 10 feet of board length.
That’s my checklist. Simple. Follow it, and your sealant application will pass inspection every time. Period.
