Carpenter ants, first of all, do not eat wood, they chew it with large clamp-like mouth parts at a surprisingly fast rate for their size, it takes years of having a constant and growing carpenter ant infestation to damage your house to the point that it becomes physically unstable. That being said the longer this issue goes the less likely it will be that you will ever manage to sell your home. After a point, the house simply must be condemned and demolished.
Carpenter ants are a highly destructive species of ant that does not eat wood but does drill through it. They make their nests in damp rotting and wet wood and prefer it to dry wood. However, when a queen is making a new colony she may decide to build it in dry wood for the increased safety.
The biggest issue with carpenter ants is that they are very hard to spot. You can have a carpenter ant infestation for years and not even realize it. They could be crawling around in your walls right now, chewing through your wooden furniture and making a mess of your walls. Eventually, they will chew through the whole house and bring it tumbling to the ground, not soon, but also not so far. They are capable of laying waste to surprising structures of wood and can ruin your antiques in a minute.
You can tell you have carpenter ants in a few obvious ways. Worker ants foraging will often travel on the outside of the wall, if you see long lines of carpenter ants on your walls then it is guaranteed that you have a very large and very serious infestation to deal with. You can also check your walls and wooden areas like stairs and furniture for small oblong holes with piles of something called Frass. Frass is a word to describe the pile of powdery wood shavings, ant parts and feces that makes up the tiny piles underneath the holes they dig in the wall. This material is carried out by the workers and dropped outside the hole. The carpenter ant works on a tiny scale, and it can take years for them to cause instability in wood. If it’s your deck you are worried about then you will want to paint it to protect it from some types of wood-eating/chewing insects.
Another clear and obvious sign of a major infestation is winged ants. If you see winged ants try your best to kill them because the females are about to become new queens of their colonies and that can mean a major expansion in the ant population as a dozen queens make new nests. These winged ants appear when a colony reaches maturity. They fly around in a mating dance and then the males die and females tear off their wings. This is why you may find dead winged ants and wings near the floor under your windows. That is likely where they mated.
Carpenter ants are not termites, they do not live in and eat the wood, so killing them is possible with homemade or domestic methods. The best option for ants on the exterior is to simply clear away all wooden detritus which gives them places to build nests, so they can prepare to make a satellite colony in your home. The best domestic options are boric acid bait which is a type of chemical salt, not like table salt, but it has the same toxicity to humans as table salt. What it does to ants is it tears through the ant’s organs killing them from the inside. You can also make homemade boric acid bait balls out of boric acid, sugar, flour and water. There are other treatment options like clove oil which can be sprayed or dripped into the openings of the nests. The scent and liquid will kill their nerves and cause paralysis and death. You can also make use of an ancient substance mined from the ground. This is a silica powder so fine it floats in the air. You can use it to dust around baseboards and anywhere ants are. You can also puff it into the openings using a crack and crevice device that can be purchased at a hardware store. The name of the chemical is diatomaceous earth and is highly effective in slicing open the waxy layer that keeps the liquid inside an insect. When this is cut the fluid leaks out and the insect desiccates.