Why do you think that a spiritual being will need any sort of door to come inside your house or space?
Spiritual beings are not solid ,they are energy and can go through any type of material even through your physical body.In fact if you could see and hear them your house would have looked rather busy ,especially if you do magic on regular basic.They can also move very fast and go through dimensions and great distances very fast if they wish so.
The only being that need doors are us (human beings).
Ouja is not a door ,it is communication tool ,like your phone for example.If something plays the role of door that is you and your energy calling them forth.You can pick the phone and call good and not so good friends.It is same with any other sort of spiritual communication tool.What goes around ,goes around.If you project negative energy and have negative motives you will attract negative beings and vice versa ,with few exceptions.
Talking is not the only way that we communicate,so you do not even need to do spell to attract spirits all you need to do is to project this desire through your energy and they will know that your house is open for them.Having typed that ,that does not mean that they do not come just because you said they should not.It is up to you to create and reinforce boundaries and rules and this is gradual process ,does not have to do just with saying few words and forgetting about them afterwards.With spirits it is work in progress same as with people.As with people you need to win their respect if you want any respect towards what you say and what you try to reinforce in your own space.