surface area over ceiling gyp

[matleonii]

I'm having a problem with my surface exposed area schedules. Many projects I work on have ceiling gyps under the actual concrete ceiling. This means that this portion of the wall surface area above the gyp should no be included in the schedule. The image attached should help you understand.

In order to get rid of this unused area I was creating gyps with the slab tool and making them as high as the actual empty space (see image 2). Doing so the "empty" area would not be considered exposed area. This way it would not be counted on the schedule of exposed area.

But this is a poor workaround. Is there a way to properly do this?

Somethings I have considered: Use the zone tool to specify the area of the wall that should be considered "exposed", this way I can determine to which height I want the wall surface to act. (tried but could not do such thing)

Any tips on how can I calculate theses areas properly? If I could do so without having to model 2 wall on to of one another or using a profile wall it would be awesome. This is something so common that I want to make this as simple as possible to work with.

[Barry Kelly · Accepted solution]

Create a building material for the air space.
Make it stronger than the gypsum used on the wall.

If you ceiling has a constant space below the slab, then create a ceiling composite (gypsum/airspace).
If the space varies then just add a standard slab above the ceiling and adjust the thickness to suit.

So long as this ceiling slab overlaps the gypsum in the wall it will cut it away.
The air space needs to be stronger that the wall gypsum but weaker than the wall frame and the outside skin.

If you use a composite ceiling, the ceiling gypsum material needs to be weaker than the wall gypsum.

It is basically a game of strongest building material wins.
They will cut away the weaker ones and and therefore they will not schedule.

If you don't want the ceiling/airspace to overlap the wall and trim it automatically, then stop it so it just touches.
Then if you use a 'Surface Schedule' it should ignore the touching surfaces.


Barry.

[Laszlo Nagy]

Maybe you can create an Expression-based Property that would calculate the desired surface.
You know the Surface of the Wall and the Height of the Wall.
You could create a Property that would specify the non-exposed Height of the Wall.
Then you would calculate the Exposed Surface like this:

Surface * (Height - Non-exposedHeight) / Height

[matleonii]

Barry wrote:
Create a building material for the air space.
Make it stronger than the gypsum used on the wall.

If you ceiling has a constant space below the slab, then create a ceiling composite (gypsum/airspace).
If the space varies then just add a standard slab above the ceiling and adjust the thickness to suit.

So long as this ceiling slab overlaps the gypsum in the wall it will cut it away.
The air space needs to be stronger that the wall gypsum but weaker than the wall frame and the outside skin.

If you use a composite ceiling, the ceiling gypsum material needs to be weaker than the wall gypsum.

It is basically a game of strongest building material wins.
They will cut away the weaker ones and and therefore they will not schedule.

If you don't want the ceiling/airspace to overlap the wall and trim it automatically, then stop it so it just touches.
Then if you use a 'Surface Schedule' it should ignore the touching surfaces.


Barry.

That is a great solution. I had only to make an adaptation: create a second air material in Archicad, having one that is Strong and another that is weak (in priority terms). Sometimes I create some gyps details or I insert some objects in this empty space I mentioned. If I use the strong air material it would (unless I made some solid operations) erase my details. With the weak air material it does not affect my model, but only covers the unpainted surface.

It is nice that by changing the slab to the strong air material i can obtain the effect you discribed.

I attached an image of this so that it is clear to others that might be facing the same issues.

Thanks for your tip! It helped!

[matleonii]

LaszloNagy wrote:
Maybe you can create an Expression-based Property that would calculate the desired surface.
You know the Surface of the Wall and the Height of the Wall.
You could create a Property that would specify the non-exposed Height of the Wall.
Then you would calculate the Exposed Surface like this:

Surface * (Height - Non-exposedHeight) / Height

This is a smart method as well. Tho I found the "air modeling method" easier, since the non-exposed height might change on the interior and exterior face of the wall. At least the way I tried (I might have done it poorly) it was a bit boring to add a measurement of the empty space in each wall.

please correct me if I understood it wrong.

[Laszlo Nagy]

No, you understood it right. You should use whichever solution you find better and easier to do.