Of course it would be OK to use money you've saved for emergency expenses. (Better than debt!) It would be way better to have another savings fund for big expenses such as a new roof or sewer line. Think about all the possible big expenses you'll have--will the roof need to be replaced in a year? in 5 years? Start saving towards those expenses.
Why not just use the emergency fund? Because you worked hard to save it up so you would be secure if your dh lost his job. What if he loses his job and the roof needs to be replaced at the same time?