The Ultimate List of Silicone Sealant Alternatives to get you Through the Global Price Hike

Why are the prices of Silicone Sealants rising?
How do I choose a suitable alternative for silicone sealant?
How do I repair a failed silicone sealant joint without silicone availability?
Can I use Polyurethane Sealants?
What are Hybrid Sealants? Can they be used instead of standard Silicone Sealants?
Tremco CPG recommended product alternatives for specified Silicone Sealants?

Silicone sealants are used in a variety of construction applications, including the residential, commercial, industrial and infrastructure sectors, mainly as a sealing or bonding agent.

Different silicone sealants can offer different properties including UV stability, high movement and elongation, tenacious adhesion, and exceptional weatherability. Typical applications for silicone sealants include expansion and control joints, perimeter caulking, structural glazing, and Insulated Glass (IG) units. Silicone sealants possess properties that allow them to be used for indoor and outdoor applications, and they adhere strongly to most substrates such as aluminium, glass, steel, painted metal, plastic, stone, concrete, and brick.

As a result of recent global supply chain disruptions, the raw material used for producing silicone sealants is facing a serious shortage. Therefore, more and more building suppliers are offering alternative forms of sealants to industry professionals in order to continue business operations without compromising on quality.

Why are the prices of Silicone Sealants rising?

A recent major global supply chain disruption has resulted in significant raw material shortages and sent prices up by 300% in less than two months in 2021. This supply disruption is predicted to last through to the first half of 2022.

The cause of this global silicone shortage can be attributed to a number of reasons:

Prolonged outages at major silicone producers in 2020 and 2021.
Power-rationing orders in China heavily impacting silicon metal production - an energy-intensive production process (China produces 70% of silicon metal globally)
There has been a limited number of major investments in silicone production outside of China resulting in a constrained global raw material production and supply.
Labour shortages – Tightened border controls because of the COVID-19 pandemic have triggered labour shortages because of the constrained inflow of migrant workers which have directly pushed up manpower costs.
Severe logistical delays - Extended transit times, inadequate transportation capacity (shortage of drivers, ships, containers, etc.), and manufacturing lockdowns have led manufacturers and suppliers to increase their product prices to buffer these risks.

The combined impact of these complications has significantly restricted the availability of silicone raw materials and increased costs for manufacturers. Therefore, suppliers are encouraging the use of silicone alternatives wherever practical or possible in various building applications to provide continuation of construction.

How do I choose a suitable alternative for silicone sealant?

It is important to ask the following questions before deciding to substitute a silicone sealant:

Will it be applied for structural glazing?
Will the alternative sealant need to be weather / UV exposed?
What is the expected movement capacity required?
Will the finishing be covered or not?

How do I repair a failed silicone sealant joint without silicone availability?

There are a couple of ways to repair a failed silicone sealant joint with polyurethane technology. However, since polyurethanes will not develop adhesion to cured silicones, the existing silicone sealant would need to be fully removed. If the joint is located within a porous substrate, this substrate will likely need some mechanical abrasion to remove as much of the existing sealant as possible. If the sealant joint is located in a non-porous substrate, the sealant should be cut out as close as possible to the bond line. Sanding with a fine grit sandpaper may be needed to remove any silicone that is left within the joint.

When applying the new polyurethane sealant joint, it is recommended that the polyurethane extend ¼ inch onto the substrate on either side of the joint. This will ensure the material is bonding to fresh substrate.

Can I use Polyurethane (PU) Sealants?

Polyurethane sealants are a popular choice for both new and renovation projects. Polyurethane sealants are mostly employed in horizontal joints or non-sagging vertical applications and are available in single and multi-component formulas. When considering using a PU sealant as a substitute to Silicone, it is important that you consult with an industry expert who can advise on the correct solution.

illbruck's SP523 Hybrid Sealant for Facades

What are Hybrid Sealants?
Can they be used instead of standard silicone sealants?

Hybrid sealants combine the benefits of high-performance polyurethane and silicone chemistry. These technologies combine to create a hybrid sealant that combines the durability and paintability of a polyurethane sealant, with the weathering and UV resistance of a silicone sealant. Hybrid sealants are a great option when selecting an alternative to standard silicone sealants.

Recommended Silicone Sealant alternatives by Tremco CPG

Substrate / Application	Silicone Typically Used	Alternative Sealant	Additional Remarks
Concrete	Spectrem 2 SG555 SG556	SP523 SP623 PU523 illmod 600 Willseal	Hybrids and PU exhibit excellent unprimed adhesion to concrete, and both are paintable. Illmod 600 can provide superior movement accommodation with zero mess or cure time. Willseal can also accommodate very large joint widths.
Natural Stone	Spectrem 2 SG555 SG557	SP523 SP623 PU523 illmod 600	Hybrids and PU exhibit excellent unprimed adhesion to stone with no risk of staining and both are paintable. Illmod 600 can provide superior movement accommodation with zero waste or mess
Stucco	SG555 SG556 SG558	SP523 PU523 illmod 600	Hybrids and PU exhibit excellent unprimed adhesion to stucco with no risk of staining and both are paintable. Illmod 600 can provide superior movement accommodation with zero waste or mess
Dryvit / EIFS	Spectrem 2 SG555 SG557 SG558	SP523	Hybrid sealant will provide a very similar performance and appearance to silicone with the added benefit of being paintable.
Window and Door Perimeters	Spectrem 2 SG555 SG556 SG557 SG558	SP523 SP623 PU523 illmod 600	Hybrids will generally provide better adhesion to dissimilar substrate than silicone with the added benefit of being paintable. Illmod 600 seals instantly with no mess or waste and can cope with wide joints.
Flashings	Spectrem 2 SG556 SG558	SP523 SP623 PU523	Hybrids will generally provide better adhesion to dissimilar substrate than silicone with the added benefit of being paintable.
Internal Joints (Dry)	SG556	SP523 SP623 TREMflex 834 SP030	Hybrids will have similar appearance and performance to silicone with the added benefit of being paintable. Crystal clear hybrids are also available. Siliconized Acrylic is an excellent, paintable, fast cure gap filler with superior acoustical properties.
Internal Wet Areas	SG556 AF	SP523 AF	Hybrids containing fungicide are available with the added benefit of being paintable.
Curtain Wall Sealing and Bedding	SG556 SG558	SP623 Tremco Butyl Sealant	Hybrids will bond and adhere to aluminium and glass. Butyl has superior sealing qualities.
Glass	Spectrem 1 Spectrem 2 SG555 SG556 SG558	SP523	Hybrids exhibit excellent adhesion to glass.
Vinyl and Plastic	Spectrem 2 SG556 SG557	SP623	Hybrids offer excellent stain resistant bonding to plastics and can also act as an adhesive.
Wood	Spectrem 2 SG555 SG556 SG557 SG558	SP523 illmod 600	Hybrids offer excellent stain resistant bonding to wood and are paintable. Illmod 600 offers superior movement accommodation, non-staining and zero mess or wastage.
For product recommendations outside of Asia, please contact your local office to discuss with one of our specialists.

Disclaimer: This article is written as a guide for proper selection of non-silicone alternatives for common applications. As is best practice on all installations, and while this document is meant as a guide, the installer should always follow the guidance of the product manufacturer, as well as carefully reading the products’ published application instructions and datasheets.

Need help choosing the right silicone sealant alternative?

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As experts in a wide range of construction product technologies, Tremco CPG provides the solutions to engineer structures that are more efficient to build and maintain, are virtually impervious to the elements, and can provide a multitude of desired finishes. At Tremco Construction Products Group (CPG), we’re committed to shaping the future through innovative approaches and sustainable solutions.