As scrutiny of building durability and indoor air quality increases, architects and specifiers are looking beyond price when choosing sealants

For years, sealant has been treated as one of the cheaper, more interchangeable parts of a build, with price often carrying more weight than performance. But as the construction industry pays closer attention to sustainability, durability and whole-of-life value, even the smallest products are being asked to prove how well they will hold up over time.

A sealed joint has to do several jobs at once. It needs to keep water out, absorb movement between materials, bond to different substrates, and resist UV and weathering for years, all without releasing harmful VOCs indoors.

Few conventional sealants manage all of that. Most trade one property off against another, and when that trade-off is poorly judged, the cost gets paid twice, first in the VOCs themselves, then in the embodied carbon of replacing work that failed too soon.

It’s really a sustainability story, even if it isn’t always told as one. A sealant with green credentials on paper isn’t worth much if it fails in eight years instead of twenty-five. Durability is what keeps material out of landfill and buildings out of the repair cycle. That’s why specifiers are starting to look at lifecycle performance alongside VOC emissions, rather than treating sealant as just another low-cost consumable.

Beyond silicone and polyurethane

Much of this comes down to what the product is made from. MS Polymer (Modified Silane Polymer) is a different base to the silicone and polyurethane chemistries that have dominated the category for decades.

It bonds to most common construction substrates without requiring a primer, and can be applied to damp surfaces where fully dry conditions aren’t practical. During cure, shrinkage is minimal, and the cured material remains permanently elastic rather than hardening or cracking with age, allowing it to accommodate both normal and, where required, more extreme building movement. MS Polymer sealants are solvent-free, isocyanate-free, low in VOCs, resistant to mould, and, unlike conventional silicone, can be overcoated with paint.

“A lot of the advantages of MS Polymer aren’t things you’d notice unless you’re the one applying it,” says Evan Olver, co-founder of Olmurtech. “Being able to bond to a damp substrate, not needing a primer, having it stay flexible instead of cracking a few years in, that’s the difference between a job done once and a job done three times.”

Nowadays, some MS Polymer-based products go a step further. Tec7, for example, functions as a structural-grade adhesive as well as a sealant, reducing the number of products an installer or specifier needs to source and stock on site.

Indoor air quality isn’t optional anymore

VOC emissions get raised often enough in these conversations that it’s worth being specific about why they matter. VOCs off-gassed from building materials are a direct contributor to poor indoor air quality, and the risk isn’t limited to the finished building. Tradespeople face the highest exposure during application and cure, when concentrations peak, while occupants can continue to be exposed at lower levels for some time after a space is completed or reoccupied

In simple terms, the lower the VOC, the lower the risk of health hazards, and the greater the contribution to a healthier building overall.

But the most important aspect is verification. Just because a product claims to be low-VOC doesn’t make it a fact. What really counts are independently tested and regularly updated emissions results, which provide the evidence that specifiers are increasingly seeking.

The difference between a claim and a certification

This is where independent certification matters, because it turns a claim into something a specifier can check for themselves. One example is the PlatinumHEALTH HealthRATE certification under Global GreenTag’s PHD program, which independently assesses a product’s VOC emissions, hazardous chemical content and potential impact on occupant health, alongside ethical manufacturing, health, safety and eco performance more broadly. Tec7 is Australia’s first in category for construction adhesives and sealants to receive this outcome. It is not a one-off award either, with products reassessed periodically to confirm they continue to meet the standard.

The testing also aligns with major green building rating systems, including LEED®, WELL and Green Star® Credits. That doesn’t mean a certified sealant earns Green Star® points by itself. Rather, its independently verified low-emission performance can help support relevant credits within a project’s wider submission, depending on the materials, design choices and documentation used across the project. Green Star Credits, LEED® Credits and WELL Features can now be earned when working with Green Building rating systems and certified products like Tec7’s.

“Anyone can print ‘eco-friendly’ on packaging,” says Olver. “What we’ve tried to do differently is make sure the claims are backed by testing that specifiers can actually go and check for themselves. That’s a slower, more expensive way to do things, but it’s the only version of ‘sustainable’ that actually means something.”

The future of construction is green

Durability doesn’t always get talked about as a sustainability feature, but it should. The most sustainable option isn’t the one with the greenest label; it’s the one that lasts the longest. A building that needs fewer repairs has a smaller overall impact than one in constant patch-up mode, whatever any single product’s label says.

None of this is about one product being better than every other option out there. It’s about a change in how sealant gets chosen in the first place, weighing verified performance, air quality, durability and sustainability together, rather than picking whatever’s cheapest or has the lowest VOCs.

That’s the real question specifiers are asking now, not which sealant costs the least, but which one actually protects the building for as long as it needs to stand.

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