Methods and apparatus for mixing and applying a bead of material. For example, the bead of material can be used to seal gaps cracks and seams of a building. The apparatus includes a supply machine and an applicator. The supply machine provides each of the parts of the material to the applicator at a controlled rate. The applicator mixes the parts of the material at a nozzle. The applicator provides a bead (rather than spraying) of the mixed material through the nozzle. The bead of material may be applied in a precise manner to seal gaps, cracks and seams of an existing building and/or the bead may be provided during new construction of a building between components of the building.