Our main brands website
Main countries
  • Product


Construction grade silicone suitable for plaster and concrete.

Product overview

Bostik Build is a high quality neutral curing, low modulus 100% silicone sealant that provides a permanent flexible, durable, watertight seal for general purpose sealing. It exhibits excellent adhesion to alkaline surfaces such as concrete, fibrous cement, mortar, and plaster. It also offers excellent primerless adhesion to many non-porous materials e.g. ceramics, glass, enamel, porcelain, coated wood, painted surfaces, canvas, some rubber, most metals (mild steel, stainless steel, aluminium, copper, tin, galvanized iron, brass or zinc) and some plastics acrylics (epoxide, acrylics, polyester, polyacrylate, polycarbonates, polystyrene, formica, fiberglass, polycarbonates and rigid PVC).The sealant is extremely resistant to UV radiation, weathering, ageing and water, and offers excellent chemical resistance and is unaffected by alcohols, dilute acids and alkalis, soap and household detergents. The sealant remains flexible over a wide range of temperatures from -40°C to 120°C. It also performs as an excellent adhesive on non-porous surfaces where an elastic gap-filling bond is required. It has a non-sag rheology and can be applied to vertical surfaces.


  • Suitable for internal and external sealing applications, waterproofing and weatherproofing.
  • Sealing of connecting and expansion joints in the construction industry e.g. sealing of expansion and connecting joints in walls and floors.
  • Sealing of gutters, gutter outlets, and around building flashes.
  • Sealing of joints between glazing and supporting structures.
  • Perimeter sealing of doors, windows and cladding panels.
  • Sealing of double glazed units.
  • Mounting of small mirrors.
  • Sanitary ware applications i.e. sealing around bathroom and kitchen fittings, baths, showers and sinks.
  • Sealant for the electrical and electronics industries e.g. encapsulation of wires, insulating appliances.
  • Sealant in silo and container construction.
  • Suitable for bonding and mending tasks where elastic gap filling bond is required.

May become discoloured in contact with some organic elastomers, which tend to bleed oil or solvents into the silicone, e.g. EPDM, APTK, Neoprene and Bituminous surfaces. Not suitable for contact with natural stone i.e. marble, granite, quartzite as it may discolour the surfaces. Will not adhere to some plastics such as polyethylene, polypropylene and Teflon. Do not apply sealant when relative humidity is below 10% - cure rate will be affected.

NOT SUITABLE FOR FISH TANKS (contains a fungicide).

NOT paintable. 




  • Bostik DIY South Africa Badge Waterproof
  • Bostik DIY South Africa Badge Acid free
  • Bostik DIY South Africa Badge Non toxic
  • Bostik DIY South Africa Badge Non drip formulation
    Non-drip formulation
  • Bostik DIY South Africa Badge Permanently flexible
    Permanently flexible
  • Bostik DIY South Africa Badge Interior Exterior
    Interior & Exterior
  • Bostik DIY South Africa Badge UV Resistant
    UV Resistant

Documents or Resources


  • Ensure surfaces are clean, dry and free of loose materials, dust, grease, rust and other contaminants.Use backing material when sealing deep cavities. If the area being sealed needs to be painted, ensure that the paint has dried before applying sealant.
  • Use masking tape to get a clean, even sealant line and to eliminate cleaning difficulties on porous surfaces.
  • Remove tape after silicone application before the sealant skins.
  • Cut the tip off the cartridge and screw on the nozzle.
  • Cut the tip of the nozzle at an angle to achieve the desired bead size.
  • Apply with a caulking gun in a continuous bead to the prepared joint.
  • Remove unwanted silicone immediately.
  • Smooth down after application within 3-5 min before skin formation occurs, by using a flat or rounded tool.
  • Sealant dries to touch in 1 hour and reaches full cure after approximately 24 hours.

Frequently Asked Questions

Stuck in a rut and not sure which sealant is suitable for your application? Call our Sticky Questions Helpline during office hours on 0800 222 400 for technical support.

To maximize the shelf life of an opened silicone cartridge, we recommend that the nozzle be removed and a piece of plastic placed over the cartridge tip after which the nozzle must be screwed back on. A large screw inserted into the nozzle tip also helps to extend the life. Store in a cool environment.

Please call our Sticky Questions toll free helpline during office hours on 0800 222 400, or send an email info@stickyquestions.co.za.