Crushed eggshells also help. Some people like to use saucers of beer to attract the snails. Or grapefruit rinds. Snails and slugs like fermenting materials. Dispose of the pests after they've fallen in.
Persistence is the answer in trying to control snails.
Wet weather, of course, increases the problem, and at such times, gardeners often use one of the commercial slug and snail baits. Follow label directions, and be careful of applications in areas where your pets may wander. A repair job is in order due to a foundation problem, and these plants will need to be dug up temporarily. The repair job may take a day or two. Carefully dig up the shrubs and move to a shady area.