CT1 Unique Sealant and Construction Adhesive 290ml

In-Depth Look

CT1 has gone from a niche Irish product to one of the most talked-about sealants in the UK trade over the past decade. Its reputation was built on genuine performance in difficult applications: wet surfaces, non-porous substrates, and situations where standard silicone or polyurethane sealants fail or are unsuitable.

TRIBRID Polymer Technology

CT1 is based on TRIBRID polymer chemistry, an evolution of HYBRID polymer technology. Unlike standard silicone (which doesn’t accept paint and has limited adhesion to many substrates) or polyurethane sealants (which require dry conditions and can contain isocyanates), CT1 bonds to virtually any combination of building materials without primers, cures in wet conditions, and can cure fully submerged. Substrates include glass, metal, wood, concrete, tile, UPVC, fibreglass, and most other building materials.

Performance Characteristics

The cured product is permanently flexible and maintains adhesion through thermal movement, making it suitable for joints that expand and contract seasonally. The temperature range of -40°C to +100°C covers all UK exterior applications. CT1 is UV stable without yellowing, overpaintable once fully cured, and demonstrates better mould resistance than standard silicone sealants in wet areas.

Trade Applications

CT1’s following among plumbers relates to its ability to seal around waste pipes and sanitary ware fittings without waiting for wet surfaces to dry. Tilers use it for movement joints in wet rooms and large format tile installations where grout alone is inappropriate. Roofers use it for emergency sealing in wet weather when other products cannot be applied. The CT1 TRIBRID range also includes metal-specific and mirror-safe variants for substrate-specific applications.

Verdict

CT1 justifies its premium price through genuine versatility. Not a universal replacement for all sealants, but for difficult applications it regularly outperforms standard products and reduces the need for remedial work.

How It Compares

CT1 is a hybrid polymer sealant and adhesive, which means one cartridge both seals a joint and bonds two surfaces together. Its TRIBRID chemistry is solvent-free and isocyanate-free, and the product file says it bonds to a wide range of building materials, including on wet surfaces. That is why it has built a following among UK tradespeople.

Its usual comparisons are with other hybrid and construction adhesive products. Sikaflex 11FC and Sikaflex 291 are well-known products from Sika, widely used in construction and marine work. Soudal Fix All and Evo-Stik Serious Stuff are popular general purpose sealant-adhesives found at builders’ merchants. Each is formulated differently, with its own substrate list, cure behaviour and paintability, so read the data sheet of the specific product before assuming it matches CT1.

CT1’s distinguishing points in the file are the ability to work on wet surfaces, to cure fully submerged, to stay permanently flexible, to resist UV without yellowing and to be overpainted once fully cured. The temperature range is -40°C to +100°C. It also has better mould resistance than standard silicone in wet areas, according to the file.

The compromises are listed too. CT1’s cure is slower than some adhesives. The file is clear that it is not a universal replacement for every sealant, and that its strength is in difficult applications where standard products struggle.

Silicone remains a sensible choice for ordinary sanitary joints where you do not need to paint or bond. CT1 is the better option when you need to stick things together as well as seal them, or when conditions are damp and awkward. The CT1 range also includes metal-specific and mirror-safe variants, so check the tube you are buying suits the job.

Common Questions

Can CT1 be used underwater? According to the product file, it can be applied on wet surfaces and cure fully submerged. That makes it useful for repairs where drying the area first is not possible. For any specific use, check the CT1 data sheet and cartridge instructions to make sure the application is approved.

Can I paint over it, and when? Yes. The file states CT1 is overpaintable once fully cured. It does not give a time, and cure speed depends on the thickness of the bead and conditions, so follow the cartridge or data sheet instructions. Painting too early risks a poor finish. Standard silicone, by contrast, does not accept paint.

Is it a good swap for silicone around sanitary ware? The file says plumbers use CT1 to seal around waste pipes and sanitary fittings without waiting for wet surfaces to dry, and that it shows better mould resistance than standard silicone in wet areas. Unlike silicone it can be painted once fully cured. Check the data sheet and the colour range for the joint you have in mind, and prepare the surface by removing loose dirt, grease and flaking material first.

Does the slower cure matter? The file lists a slower cure than some adhesives as a downside. In practice, heavy or vertical items may need supporting while the product sets, and the joint should not be stressed too soon. The cartridge and data sheet give the manufacturer’s guidance on handling and full cure, so follow those rather than a rule of thumb.