# Floor/Ceiling innermost and outermost layers Dilemma

Hi, I have one zone in top of another, which means that they both have a shared floor/ceiling surface.

The construction for this shared construction is a concrete slab, a thick stone floor finish to provide some thermal mass, below the slab there is insulation and a drop down gypsum ceiling.

When creating the construction in HB for grasshopper I define it as follows:

• Layer 1 (Outmost): Stone finish
• Layer 2 : Slab
• Layer 3 : Air cavity
• Layer 4 : Insulation
• Layer 5 (Innermost) : Gypsum ceiling

My question is: how is EP going to interpret this. What are the innermost and outermost layers according to each of the zones? Or does EP maintain Layer 1 always on top (Z axis) and Layer 5 as the bottom layer (Z Axis).

(My logic tells me that for each zone, the innermost layer will be the stone finish, but this is not true).

It is important for me that the Floor finish is always on top so I capture solar radiation on it.

So after I got back to my computer I was able to test out the problem a little bit, I am going to answer my own quesiton:

When I solve adjacencies between an upper and lower zone: the lower zone gets its upper surface assigned as ceiling while the upper zone gets its bottom surface assigned as floor. When I looked into examples of constructions in the EP Library I found that indeed the layer order gets mirrored:

This is a bit of a sad thing to see myself having a conversation with myself ā¦
(Iām still learning, hope to reach your high level discussion soon)

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