Incorrect room volume delimitation in Revit (from dynamo)

Good afternoon everyone, first of all thank for the many doubts that I have solved in this forum.

I am at a dead end in the construction of a parameterized vault-wall model, previously carried out in dynamo with the aim of doing a modular analysis of houses.

I attach two models, one solid and the other one with surfaces in Revit. In the solid model I find that the volume of the enclosure defined by Revit is not the real, as you can see in the attached images (planning table 31.5 m3 versus the real ones verified in Dynamo 38.89 m3), all the elements are characterized to delimit an enclosure and are categorized as walls, floors or ceiling respectively.
In the simplification of the surface model despite the fact that the elements delimit the enclosure, they cannot close it.

On the other hand, I would like to know if someone knows any node in dynamo that allows us to introduce a surface or solid that defines a wall, allowing us to enter “wall type” (leaving aside the face option for masses, since the objects are modeled directly in dynamo).

Any clarification is welcome, thanks in advance and good day to all.