Preparation Tips Before Installing Sealants

Priming the surface before caulking is integral to achieving a smooth and even application. Often, the reason why sealants start to fall apart way before they are supposed to is due to a lack of surface preparation and the improper application of the sealant. This is crucial as most manufacturers will require that you follow the labeled instructions to a T to be considered eligible for the warranty. This article covers the preparations you should make before installing the sealants.

Cleaning The Surface

To ensure your sealant will have maximum adhesion strength, the important step is to clean your surface before caulking. Ideally, it would be best to do this with a solvent to remove any dirt, oil, debris, or remaining old caulk from before that has already been removed. However, you will first want to ensure that the solvent is compatible with the substrate to avoid damaging it. We’d recommend using 70% isopropyl alcohol mixed with water to remove any non-oily layer of dust and dirt. However, if your surface has a layer of oil combined with dirt and debris, use degreasing solvents such as acetone or Toulene. When cleaning, use two different cloths – one soaked with solvent and one dry and clean to remove the solvent and prevent contaminations from repositing into the solvent.

Priming The Surface

While priming isn’t necessary for caulking, it is a good measure to ensure maximum adhesion strength and durability. To meet the eligibility requirements for the warranty, you should always follow the manufacturer’s guideline of priming if it is recommended. Priming requires a surface that is already clean and dry; therefore, the previous cleaning step is integral in making this process successful. The method preferred by many professionals is dipping a clean, lint-free cloth in the primer to apply a thin film of it on the surface and a clean brush to apply the primer to harder-to-access areas and more textured surfaces. Don’t go overboard and wait till the primer dries before installing your sealants.

Packing The Surface

Before applying the sealant, estimate how deep the gap is. If it is more than ½” deep, you will require a backing rod to control the amount of caulking used to prevent joint wrinkling, as this could result in a premature loss in adhesion strength. In addition, the backing rod also allows air and moisture to flow to the back of the sealant, which is integral in quickening the curing process.

This will also be affected by the use of primers, which will help significantly in expediting this process. Therefore, the ideal time to seal these openings is when the surface is cool and will be experiencing the least possible changes in temperature and material properties, such as the late afternoon.

Sealing The Surface

When applying the sealant, ensure it fills up the entire gap and reaches the surfaces you wish to cover to prevent adhesion issues. Use a positive pressure technique, where the sealant is pushed and applied ahead of the tip. If the cavity is not filled properly using the correct application method, this could result in short durability and weakened adhesion. In addition, the cold weather conditions can aggravate this issue as any temperature lower than 40°F is the ideal level for frost to form. Therefore, do a quick last-minute inspection to check if the surface is frost-free and dry before applying in cold weather conditions. If you encounter this problem, warm up the surface with a hairdryer or use 70% isopropyl alcohol to assist in drying.

Tooling The Sealant

The last step in caulking is to tool the sealant before the skin is formed. You can use various tools to achieve a smoother and even finish. One of which is to use spatulas or plastic spoons to press the sealant further towards the backing material and fully occupy the joint surfaces or cavity. Avoid using liquid tooling aid for the best result, as this could interfere with the curing process, creating an uneven and distorted surface.