Ant Damage to a Cedar Deck

Carpenter Ants

• Carpenter ants are common pests throughout the temperate areas of the world and will take up residence not only in dead and dying trees but in treated woods such as cedar decking, especially if it is close to a food source. The typical colony consists of thousands of individuals and both a parent nest and one or more satellite nests. Either the parent or the satellite colony can be created in the decking, which can make the colony difficult to get rid of. Carpenter ants don't eat the wood that they chew through, instead they gnaw out an extensive network of tunnels to house the colony. There will also be larger rooms called galleries throughout the nest.

Identifying Damage

• Carpenter ants gnaw through the wood at a regular pace, disposing of the freshly chewed wood outside of the nest. Look for small, round holes that go into the decking; if the damage has been done by carpenter ants, there will also be a pile of fine sawdust outside of the nest. The size of the pile can give an idea as to how extensive the unseen damage is.

  A newly established colony -- and recently noticed damage -- will indicate that the interior damage to the cedar deck is not that severe. However, if the colony is ignored, it will continue to grow and to excavate more and more tunnels and galleries. If left alone for long enough, this can seriously compromise the structural integrity of the deck.

Control

• To completely get rid of the ants that are damaging the deck, the nest in the deck as well as any satellite nests will have to be removed. Nests will most likely be fairly close together, and ants marching back and forth between nests will give the location away. Most active at dusk and dawn, follow the trails of ants to locate the other nests. Place bait traps along the trails that the ants are following; the workers will pick up the poison and take it back to the nest. While sprays will only eliminate the few workers that are out in the open and leave the main colony to make new workers, bait traps will kill ants that never leave the colony as well. If there are trails of ants walking across the deck, place bait traps here, but be careful of any children or pets that can be in the area.

Prevention

• Carpenter ants are attracted to soft woods that they can easily chew through to make their nests, which is why they are commonly found in dead and decaying trees. A deck made of cedar is made of a soft wood to begin with, and any moisture damage or damage from any other type of insect can make decking that much more attractive. To prevent future infestations, replace any damaged boards with new wood. Pressure-treated and sealed, stained woods are by no means impermeable to infestations, but they are less attractive than decking that has not been sealed. Cut back any trees or bushes that touch the deck and that may form a convenient bridge for the ants.