TOUPRET Fill-Flex is supplied ready-mixed in a handy tub. This highly flexible filler is perfect for gaps and cracks, ideal for skirting and architraves where movement is possible. Its flexible formula moves with the substrate and won't crack. Suitable for both internal and external use, it adheres to paintwork with no need to spot prime. It can be used on new or renovated substrates, either unpainted or painted gypsum plaster, plasterboard, cement, concrete, cellular concrete, breeze blocks, bricks and stone.