Caulking tips

Caulks - mainly silicone and urethane based caulks - can be tricky to apply for inexperienced homeowners. Latex based caulks are much easier to use...

Read carefully the instructions on the caulking cartridge, and pay close attention to preparation.

Preparation is often as important as installing the caulk or choosing it.

Caulking Tip: Cleaning and removing

Removing old caulk or paint residues is very important, but often not sufficient, namely in exterior joints.

Porous materials like masonry or wood may need scrapping, and also brushing and dusting, while non-porous materials like most metals require cleaning with an adequate solvent.

Sealing caulk Cleaning dirt and grease with water is often sufficient, but cleaning oiled surfaces may demand a proper solvent...

Caulking tip: Primer application

The application of a primer on both sides of the penetration is necessary or advantageous in many cases. It depends on the caulk (pay attention to the specifications of the product) and on the materials associated to the gap.

Caulking tip: Applying Caulks in Critical joints

On critical joints, caulking should remain flexible and strong, and to have it the material should only adhere to two surfaces (not to three).

You may use a backer rod between the joints to get it: the caulk will not stick to the backer rod, allowing flexibility; besides, the roundness shape of the rod will create a thinner bead and extra-flexibility...

Caulking tip: Dry surfaces and Warm temperatures

Make sure the area to be caulked is dry, and do not apply the caulk in low humidity conditions. Avoid applying the caulk at temperatures below 45°F/8°C. Otherwise, you risk moisture and cracks.

Warm temperatures are advantageous or necessary to a good adherence and a proper setting.

Tip: Caulking Guns

If caulking with a gun, keep it at a consistent angle. The right angle is the one that forces the caulk into the crack as it comes out (45º is the best for getting deep).

Do not apply too much caulking: release the trigger before pulling the gun away, or use a caulking gun with an automatic release.

Tip: Continuous stream

Avoid stops and starts when applying the caulk. Do it in a straight continuous stream, as much as possible. To avoid bubbles, the caulk should be sent and fill the bottom of the opening.

Make sure the caulk sticks to both sides of the crack (or seam...) without oozing out of it. If the caulk shrinks, reapply it; caulking should form a smooth bead, sealing the entire crack.