HB42.

About HB42

HB42 is a British sealant brand built around a specific problem that heating and plumbing engineers run into constantly: the need to seal joints, penetrations and pipe connections on systems that cannot be fully drained or dried before work begins. Standard silicone sealants will not cure in contact with water, because the moisture stops the acetoxy or neutral cure mechanism from completing. Standard MS polymer and polyurethane sealants likewise need a dry, clean substrate for reliable adhesion.

HB42’s silicone-free, solvent-free formulation was developed to solve exactly that. The product cures and adheres in the presence of moisture, not only on damp surfaces but in contact with standing water and on running leaks. For a heating engineer sealing a condensate pipe penetration through a damp wall, or a plumber making a watertight seal around a pipe emerging from a wet floor slab, HB42 delivers reliable results where a conventional sealant would fail within weeks.

The range has grown from the original all-purpose sealant to include specialist variants for UPVC repair, frame sealing, shower sealing and roof repair, all of which share the wet-surface cure that defines the brand. HB42 products are stocked through plumbers’ merchants, heating and ventilation suppliers and general builders’ merchants across the UK.

Products We Can Supply from HB42

HB42 All-Purpose sealant. The original product is a silicone-free, solvent-free sealant that bonds and seals on wet, damp and contaminated surfaces. It suits sealing pipe penetrations through walls and floors, UPVC profiles, metal, timber, masonry and most building substrates, and is paintable once cured. Heating engineers, plumbers and general builders reach for it anywhere wet conditions during application cannot be avoided.

HB42 Fix & Flash waterproof tape. A self-amalgamating waterproof repair tape that bonds to itself and most surfaces without adhesive, forming a watertight seal around pipes, cables, joints and penetrations. It is used for emergency pipe repairs, cable and hose sealing, and any job that needs a fast waterproof wrap without drying the surface first.

HB42 UPVC and frame sealant. A formulation tuned for sealing UPVC window and door frames, conservatory joints and exterior cladding where a flexible, paintable and weather-resistant seal is needed. The wet-surface capability is especially handy in new-build and refurbishment work where the external frame installation is exposed to rain during fitting.

HB42 Roof and flashing sealant. A high-movement, UV-stable sealant for roofing, flashing and gutter repairs on felt, metal, GRP, EPDM and bituminous roofing substrates. It can be applied in wet weather, which makes it practical for urgent repairs where waiting for dry conditions would let water ingress continue and cause further damage.

Industries

HB42 products are used by heating and plumbing engineers, builders, roofers, glaziers and general maintenance contractors, particularly on jobs involving wet or damp conditions during installation or repair, where conventional sealants would call for long drying-out periods before they could be applied successfully.