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How To Apply Caulk To A Skylight

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A skylight in your roof can provide a number of benefits for you and your family, from brightening your home by increasing the inflow of natural light, to cutting your winter heating costs. One problem that skylights are prone to are water leaks. Because a skylight is essentially a hole in the surface of your roof, it's possible for water to get past the joint where the roof and skylight meet. To prevent this, it is important that the skylight be sealed using caulk when it is first installed. In addition, this caulk will need to be regularly replaced over the years. The following will show you how to caulk a skylight.

What You Will Need

  • Caulking Gun

  • Clear Silicone Caulk

  • Polyurethane Caulk

  • Utility Knife

  • Screwdriver

  • Ladder

  • Work Gloves

  • Nonslip Boots or Shoes

Step 1. Insert a tube of polyurethane caulk into a caulking gun. Pull on the trigger several times to bring the plunger into contact with the end of the tube of caulk. Holding it at a 45 degree angle, use a utility knife to cut open the nozzle of the tube. Then insert a small screwdriver into the end of the nozzle in order to break through the seal and release the caulk.

Step 2. Put on protective work gloves and nonslip boots or shoes.

Step 3. Position a ladder alongside your roof. Make sure that it is sitting on firm, level ground before you climb up. Also ensure that it is at the right angle. You can determine this by standing at the base of the ladder and holding out your hands toward it. If (while standing straight up) you can barely touch the ladder with your fingers, it is at the correct angle. Taking your supplies with you, climb up onto the roof.

Step 4. Go to the skylight and position the nozzle of the caulking gun at the furthest corner. Pulling the caulking gun toward you, squeeze the trigger so as to apply a bead of caulk along the seam where the roof meets the skylight. Try to use a single, smooth motion so you can apply a continuous stream. If the trigger is fully depressed before you finish the side, lift the caulking gun away and release the trigger. Return to the spot where you stopped, squeeze the trigger and start caulking again. Make sure that you caulk all four sides of the skylight.

Step 5. Now go inside your home and use the same technique to apply clear silicone caulk to the inside seam of the skylight.

If this seems an overwhelming task, hire professional roofers to do the job for you.