Proper Application of Sealant

Proper application of sealants is critical to the preservation of building structures. The areas around doors, windows, sinks and showers are especially susceptible to damage from moisture if they are not properly sealed. Incomplete or improper application of the sealant will surely result in sealant failure, damage to the surrounding materials and costly, time-consuming repairs.

Surface Preparation

• When re-sealing around tubs and sinks, all of the old sealant needs to be removed. That can be accomplished with a putty knife. Damaged drywall should be replaced when sealing drywall joints around windows. Thoroughly clean surfaces before applying sealant. Non-porous surfaces can be wiped down with isopropyl rubbing alcohol to remove residual, oily film or grime. A clean, absorbent towel works well for drying the cleaned surfaces. The surfaces being sealed must be completely clean and dry prior to sealant application. Before applying sealant around windows and doors, paint porous surfaces such as drywall and concrete with a suitable primer, also a form of sealant, and allow them to dry according to the primer manufacturer's instructions. Foam backer rod should be inserted into wide gaps prior to applying sealant around windows, doors and tubs. Foam backer rod is available in sizes ranging from 1/2 inch to 1 inch and provides a solid, adhering surface for caulk and sealant.

Application

• Sealants are designed for specific purposes. Usually, several grades are available for each type of sealant. The most expensive is not always the best. Read the label carefully to ensure the sealant is suitable for the job. Always apply sealants with strict adherence to the manufacturer's recommendations, and allow appropriate drying time between coats and before use of tubs and sinks. Sealants must be applied under recommended temperature and, usually, humidity restrictions. Failure to follow these recommendations may cause the sealant to cure improperly or may interfere with the sealant's ability to adhere to the surface, resulting in sealant failure. Apply sealant around windows, doors, tubs and sinks with one continuous bead of sealant or caulk; then smooth it and complete the seal with a moist finger or smoothing tool. Most sealants can be painted, but purchasing a sealant that is designed to be painted is best for sealing around doors and any other area that will be painted. Two or three thin coats of paint should be applied on sealants rather than one thick coat.