How to know that a model is closed ? no holes?

hello everyone,
i have a model that isn’t manifold but i need to test when it is fully closed which means all faces are drawn
and there is no holes in my model ? like if it’s a cube it will be close when all 6 faces are drawn otherwise it’s still not closed ? how can i do that i tried making it a group and use manifold but my model isn’t manifold there may be some faces larger than others …
i gave an example of my model below.

roof intersection.skp (267.8 KB)

The Blue version is not a manifold solid - when it is grouped.
This is because it has several edges that have only one face.
The definition of a manifold solid is that every edge has exactly two faces - no fewer and no more !

If the Blue faces are intersected together, then it will still not be a manifold solid - because there are then some edges with one face, and now some edges with four faces !
If you erase any edges with one face what’s left should then be a solid.

Make it all inside a group NOT in the base model context.
Intersect the faces.
Collect all of the edges in that group.entities context.
I’d do it like this:

    edges_to_go << e if e.faces.length != 2
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yes i know the manifold groups but i need to know if there is no holes in my model so that i can delete the extra faces and edges, as a test if the model doesn’t contain hols i’ll delete the extra edges else i won’t. how can i know that the model doesn’t contain any holes ?

If you are making overlapping roof planes to ALL wall top edges then there be no ‘holes’ - since they will all intersect each other.
You then need to intersect these faces to cut them at those intersections.
Then run my code snippet to remove the one-face edges to form proper ridges and hips/valleys etc…