Sheds are basically miniature versions of our houses, used more for storage than for living. However, they experience the same difficulties as our homes, including insect infestations. You're more likely to find insects in sheds than in homes because sheds are typically used less, meaning that there's less to scare the bugs away and more dirt and dust tends to build up on the surfaces. Sheds are generally also less insulated and sealed, allowing room for the bugs to invade. Keep bugs out of your shed in seven steps.
Seal all cracks and gaps in your shed with silicone caulk. Even a crack as thin as 1/8 inch wide can allow ants and other small bugs into your shed. Seal around any windows in the shed, as well as all joints between shed pieces.
Sweep out the shed at least once per week to remove dirt and dust. Bugs can hide in dirt and dust and are attracted by unclean areas.
Move all food stores out of your shed, except those that are sealed in air-tight cans or bottles. Open food is an open invitation for bugs.
Set sticky traps or pest-specific traps -- ant traps, roach traps -- around the doors and windows of your shed. These traps will kill any bugs that get trapped in them; some contain bait that a single bug can bring back to a colony to kill the whole infestation.
Improve lighting in your shed. Make it so that any time you're in the shed, the lighting illuminates all corners of the room. Many bugs, including spiders, will run from areas clearly inhabited by humans.
Close the shed door whenever it's not in use, or if you're going to be in there for an extended period of time. This limits the entry points for bugs.
Treat insects with specific sprays as long as there are no pets, children or food stores that can be affected by the spray. These sprays are poisonous to insects but also to people and animals in some cases, so apply with caution. You can treat the whole shed, or just the areas in which you have seen insects.