One of the reasons that termites cause so much damage – besides their big appetites – is that infestations can go unnoticed for months or even years. Unlike many pests, termites can stay hidden in your foundation or walls for a long time, which means you’ve got to look for other signs of their presence.

The signs of a termite infestation may be subtle, but they do exist, so here’s what you should be on the lookout for:

• Stuck doors and windows: Termites introduce extra moisture into your walls and flooring, which can warp your door and window frames. As a result, windows and doors may suddenly get stuck or feel as if they no longer fit on their frames as they should.

• Frass: Termite droppings, or frass, aren’t very big and usually resemble sawdust or coffee grounds. When termites dig their tunnels, they kick out their frass, and it can end up piled near baseboards.

• Swarms: When it’s time to mate, reproductive termites leave the colony in swarms. It’s not as common to spot this as some other signs, but you may be able to see the actual swarms flying around your property.

• Discarded wings: More often than not, homeowners don’t see the termite swarms, but they do find the shed and discarded wings that termites have left behind. These wings tend to resemble fish scales, and you may find them piled around doors and windows.

• “Water-damaged” materials: Peeling paint, discolored, or drooping drywall can all come from the extra moisture that termites bring into your walls and floor.

• Hollowed wood: Wood that sounds hollow when you tap or step on it may be due to the invasive tunnels that termites create.