I have found 2 wasps alive in my loft, does that mean there is a nest being built up there somewhere?

What can i do to prevent them nesting? is there something i can buy in the diy shop?
Answer
Yes, but before buying anything, identfy where the nest is. the nest should be under the eves of the house or in a place that is out of the weather. you can buy wasp spray which shoots out a straight stream. to kill them, it is best to do it at night. take a flashlight, go to the nest and spray it. turn your light out. they cannot find you in the dark.