Best Practice: Levels locate top of (a) finished floor or (b) structural slab?

[damon.sidel]

What do you consider best practice for levels?

Is your finished floor at the level or is your structural slab at the level?

Do you set it up differently for different projects/situations?

Whatever you consider best practice, are there exceptions?

If you care to elaborate, what do you consider to be the pros and cons of each choice?

[dhurtubise]

For us it's 99% Finish Floor

[Devin_82]

We tend to have a lot of levels. We have them for TO plate, TO sheathing (slab), and TO fin flr. I have heard some say it shouldn't be a level if it isn't a view, but this is what has worked for us in the past. It causes occasional issues if you aren't paying attention because some objects, walls for example should be on the TO sheathing, but other should be based on the TO fin flr, like the windows. Our views tend to be TO sheathing (or slab), so we have to make sure when we are placing windows that we place them on the correct level.

[damon.sidel]

We tend to have a lot of levels. We have them for TO plate, TO sheathing (slab), and TO fin flr. I have heard some say it shouldn't be a level if it isn't a view, but this is what has worked for us in the past. It causes occasional issues if you aren't paying attention because some objects, walls for example should be on the TO sheathing, but other should be based on the TO fin flr, like the windows. Our views tend to be TO sheathing (or slab), so we have to make sure when we are placing windows that we place them on the correct level.

Sounds confusing! Thank you for the response.

[Devin_82]

Sounds confusing! Thank you for the response.

Yeah, it can be. But I think that its one of those things that you figure out pretty quick and that becomes pretty easy once you do. Think layers in ACAD, you had to make sure that you were on the right layer when drafting specific elements, now you have to make sure your base constraint is correct when you are modelling different elements.

The beauty of Revit (and sometimes the pain in the butt) is that there is almost always a couple of ways to do something and you get to figure out how to make it work best for you and your project or office.

[patricks]

I would NOT condone only having levels for various views. That makes things a major PITA when it comes to changing heights of something.

For instance maybe you have a Roof Eave Ht level, and your Roof Plan references that level. But then maybe you have a Parapet Ht level which is the top of your wall parapet. That level does not have any views associated with it. But if your parapet height changes, it's a heck of a lot easier to change that than it would be to go around having to change the top offset setting of all your walls, assuming they were all offset above the Roof Eave Ht level. Even worse if you have more than one parapet height.

As for floors, for us the floor level is pretty much ALWAYS the top of the concrete slab or wood subfloor deck. For finish plans we usually place thin 1/8" floors on their own workset that represent carpet, tile, etc. but the level datum itself is to the top of the slab or deck. For roofs it's typically the bottom side of the deck, which usually also coincides with the top of framing.

[jsteinhauer]

Top of Slab, because T.O. Finished Floor is dependent on material being used. I don't want to have 2-10 different levels, one for each material. Not to mention having a sloped floor.

Cheers,
Jeff S.

[david_peterson]

I provide Levels for main floors only. Platforms, Mezzanine...... top of steel.... if I were going to use anything for these little intermediate levels I'd use a named reference plane. But if you use this method you'll have to make sure that you always check what the active work plane is.
Typically I just use top of slab and use the Z-direction offset to move it to the bottom of the slab.

[dkoch]

We call it "finished floor", but the reality is that it is the top of structural slab, for the reason jsteinhauer gave. The actual floor finishes probably are not even known at the time that levels need to be set in the model, and no one is going to track all of the different net heights. Variation in the actual top of slab over the entire floor is likely greater than the delta on most of the flooring we use. Door frames and interior partitions are all going to run from top of slab, typically.

[Devin_82]

We call it "finished floor", but the reality is that it is the top of structural slab

I should clarify, when I said we have TO Sheathing /Slab and TO Fin Flr, those are specific to our project needs. We do a lot of multi-family, Type V and Type III wood structures over concrete podiums with subterranean garages. So TO Fin Flr isn't really the completely finished floor with the carpet or the vinyl or the laminate, rather it is the gypsum underlayment that typically sits on top of the structural sheathing. This is usually in the 1.5" neighborhood, so it is important for us to distinguish between the two datum points for things like interior/exterior partitions and windows or stairs. If we were just talking carpet thickness, then I would agree with everyone above and say its probably not worth it.