Project Guide

How to Caulk Like a Professional

1
Prepare the Surface
person removing old caulk around bathroom sink with a utility knife

You can apply new caulk over old caulk, but it may not stick. A good caulking job starts with a clean surface.

  • Cut old caulk out with a utility knife or scraper. 
  • Remove all dirt, dust, grease and debris. If you’re removing silicone caulk, ensure all residue is completely removed. 
  • Use a rag to wipe the joint surface with rubbing alcohol or an over-the-counter disinfecting spray. Rinse thoroughly with water and dry.


Tip: If the gap you are caulking is greater than ½ inch, press a foam tape into the space.  

2
Tape the Area
person taping around bathroom sink

Apply painter’s tape to mask off areas around the joint where the caulk should not appear. This will give you a straight line of caulk and will improve the final appearance.

3
Cut the Nozzle
person cutting the tip off the nozzle of a caulk tube

A line of caulk is called a “bead”. The further up you cut the nozzle, the smaller the bead. Reversely, the further down you cut the nozzle, the wider your caulk line will be. 

  • Read the instructions on the caulk bottle for how to cut the nozzle. Some nozzles have a foil seal that will need to be punctured, and some nozzles also need to be removed to trim an inside seal. 
  • If using a squeeze tube, remove the cap and then trim the nozzle with scissors. 
  • For rigid plastic tubes, use a utility knife to cut the tip of the nozzle off at a 45-degree angle. 
4
Apply the Caulk
person applying new caulk around bathroom sink
  • If using a rigid plastic cartridge, place the cartridge in the caulking gun. 
  • Apply steady pressure to the trigger or tube and fill the gap with an even bead of caulk. 
  • It is best to push the caulk ahead of the nozzle to ensure that it gets into the joint for a proper seal.
5
Smooth It Out
How to Caulk - Person smoothing new caulk around bathroom sink

For a neat and professional-looking finish, “tool” or smooth the bead of caulk. Lightly drag a caulk finishing tool or putty knife over the bead to smooth it. 

  • If you used painter’s tape, remove the tape before the caulk “skins over” (meaning that the product has developed a firm skin on the surface, which normally occurs after a few hours). 
  • To correctly remove the tape, lift the edge up at a 45-degree angle away from you. 
  • Caulk usually dries in about 24 hours. Wipe away excess caulk with water and a damp cloth before the it dries. Excess dried caulk will need to be cut or scraped away. 


Tip: Some clear caulks will apply white and dry clear in seven to 14 days, depending on humidity and temperature. To reuse any remaining caulk on a future project, tightly reseal the cartridge and store within the manufacturer's recommended temperatures.