For those who
know their stuff.
A high performance, gap filling sealant specifically formulated for use on moulding and trim applications. It delivers maximum adhesion and flexibility for a crack proof seal. Paint ready in just 30 minutes. LEARN MORE 100% CRACKPROOF
Stays flexible to withstand expansion & contraction without cracking
Strong adhesion to a wide variety of building substrates including non porous, smooth surfaces
Provides professional paint finish results. Won’t shine through or discolour paint.
Fast 30 minute paint ready time. Smooth easy application, low odour water clean up


Alex Flex Premium Moulding Trim Sealant is the ideal choice for sealing gaps and cracks prior to painting for outstanding finish results. It offers maximum flexibility and adhesion for a crack-proof, long lasting seal.

  • Crackproof
  • Permanently flexible to withstand high joint movement: 25% total joint movement
  • Strong, multi surface adhesion
  • Paint ready in 30 minutes with water & oil based paints
  • Excellent paint compatibility: won’t shine through or discolour paint
  • Long lasting durability 60 Year
  • 100% waterproof seal
  • Cured sealant is mould & mildew resistant
  • Easy application: guns easily, tools smoothly
  • Easy water clean up, low odour , low VOC
  • Interior & exterior use


Interior Moulding , Trim & Corner Joints

Window Frames

Door Frames

Exterior Trim


  • Sealing moulding and trim can be a tricky project if the wrong sealant is used. Multi-piece crown moulding can have up to five or more moving parts that must be sealed. Seasonal changes can cause wood trim to expand and contract, stressing seams year-round. Alex Flex provides maximum flexibility and adhesion for a crack proof seal, as well as fast paintability and no paint shiners, making it ideal for moulding and trim projects.
  • Remove any old sealant from the seam or joint by cutting or scraping it away. Then clean the area with soap and water to remove dirt, dust, grease or debris. Rinse thoroughly. Make sure the area to be sealed is clean and dry to ensure good adhesion.
  • Apply painter’s masking tape to either side of the joint before applying the sealant. Remove the tape before the sealant skins over – about 2-5 minutes. To remove, lift the edge up at a 45° angle and pull away from you.
  • To get a professional-looking finish after the sealant has been applied, smooth the bead of sealant with a caulk finishing tool dipped in water. Do this before the sealant starts to skin over, about 2-5 minutes.
  • Yes, Alex Flex acrylic latex caulks can be used in both interior and exterior applications. For exterior applications, they should be applied in temperatures above 5°C, and not when rain or freezing temperatures are forecasted before a full cure can occur. Cold weather and high humidity may slow down cure time.
  • No, it is only available in white
  • The joint size shouldn’t exceed 12mm wide by 12mm deep. If the joint depth exceeds 12mm, insert foam backer rod material into the joint before applying the sealant.
  • Before drying, they can be easily removed with soap and water. After the caulk has dried, it will need to be cut or scraped away.
  • Shiners are unsightly glossy spots that appear when some flexible sealants are painted. Alex Flex will not gloss or discolour paint.


SKU Code Unit Size Colour Dimensions
7079818440 18440 16oz / 473ml OFF WHITE 12x8.25x8.25