If you have wasps flying around because you have a wasps' nest somewhere in the roof of your house you will have to get a local pest controller to remove the nest. However, we had one once and were advised that if we could live with them until the autumn, they would die off when the colder weather arrived. And this is exactly what happened. If the wasps are just flying around your garden there's isn't much you can do. This is their most active time guzzling on ripe fruit and windfalls but colder weather normally solves the problem.
I had three wasp nests in the last couple of years and got professional exterminators in. They cost �40 and take just a few minutes with a chemical puffy spray. As they frighten me, a swarm of them is just too much to handle. I believe you can get wasp killer chemicals in garden centres and such but I wouldnt risk it. Good luck.
They wont necessarily be in the roof, there is a thousand and one places they could be, but wherever they are, they will soon be gone with the cold weather, just a few more weeks.