How to seal a space between deck boards

deck image by Albert Lozano from

A deck is a wooden platform typically installed in the yard of a home. The surface is made to walk upon, and is constructed of individual floor boards. If there are gaps in the installation that are particularly large, dirt and other residue can easily become trapped within them. A quick and simple solution to sealing these spaces is to caulk between the deck boards. Silicone caulk is an airtight sealant that is water-resistant and very subtle when applied.

Thoroughly vacuum the deck boards that require treatment. Clean up any traces of dirt or grime using a mop soaked in a mild cleaning detergent, then allow the boards to air dry.

Use a sharp pair of scissors to cut the tip on a cartridge of silicone caulk. Leave an opening that will allow you to dispense a bead of caulk no more than 1/4-inch wide.

Puncture the foil seal within the tip of the cartridge using a stiff wire, then load the tube into a caulking gun. Align the tip with a seam in between the deck boards and hold the gun at a 45 degree angle.

Squeeze the trigger to apply the silicone caulk, with the tip of the cartridge touching the targeted space. Maintain consistent pressure and draw the gun along the length of the space to fill it with the sealant.

Repeat the same procedure for other cracks in the deck. Quickly wipe any excess silicone with a damp rag before it begins to harden. Allow the sealant to cure completely over a full 24-hour period.

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