Where do you set floor levels?

[Anonymous]

I'm working on a residential project that has a basement, first floor, and second floor. On the first and second floors I will have some areas with under-floor (radiant) heating so the floor sheathing will be 1 1/8" in those areas and 3/4" floor sheathing in other areas. So I'm wondering where you all typically the "first floor height"? Currently I have it set at the top of the joists because that height will always remain the same. Though I could set it at the top of either subfloor material. I'm just curious what the standard method of doing this is. Thanks in advance.

[Richard Morrison]

I personally like to set it at the top of structural floor, and make sure that the floor is drawn as a composite slab, so that the cross section will be as accurate and complete as possible. You might want to consider whether it's really a good idea to have varying floor sheathing thicknesses. You may end up eating into any potential savings by creating situations requiring shimming, etc.

[Anonymous]

Ideally I'd go one way or the other on the floor sheathing but the cost of the radiant heating system would be astronomical were we to implement it on entire floors rather than choosing locations which would provide the greatest benefit. However, I've yet to delve into the shimming situation where the floors meet so, as you've suggested, and I've been speculating, it will likely be more headache than it is worth in the end.

As for using composite slabs. I haven't used that approach in the past simply because in the case that I needed to move/adjust joist positions I like to be able to work with the individual objects. I would think that being able to position my joists, LVLs, etc. independently would provide more complete and accurate cross sections. I am interested in hearing more about your method if you care to elaborate. I'm relatively new to ArchiCAD and the industry in general so all input is valued.

[__archiben]

Richard wrote:
I personally like to set it at the top of structural floor, and make sure that the floor is drawn as a composite slab,...

i, too, make the storey height the top of the STRUCTURAL slab, but i model my floor finishes as totally separate elements on a "finishes" layer on top of the structural floor slab.

this gives me greater visibility control ('core only' for the GAs) and allows different floor finish materials to be used over one floor area, or even within one room.

shims aside, it sounds like this would suit you atlantex?

~/archiben

[Anonymous]

~/archiben wrote:
i too make the storey height the top of the STRUCTURAL slab, but i model my floor finishes as totally separate elements on a "finishes" layer.

this give me greater visibility control ('core only' for the GAs) and allows different floor finish materials to be used over one floor area, or even within one room.

shims aside, it sounds like this would suit you atlantex?

~/archiben

Well, in my case the top of the structural slab is what will vary. The radiant heating system we'll be using is one by Warmboard which inlays the heating elements (pipes/hoses) into a 1 1/8" floor sheathing slab. It is approved for residential use in place of 3/4" structural floor sheathing. So it would seem the finish materials would be a separate issue.