IFC Wall material layers - best practice

Nigel

I am keen to hear the forum members' thoughts on how timber framed, or metal framed walls will in-fill insulation is handled IFC wall material layers.
Here in Aotearoa NZ we typically build houses and smaller buildings using 'light timber framing' similar to parts of Australia and USA.
The question is what is good practice in IFC? ![]
thank you in advance :)
(https://community.osarch.org/uploads/editor/4o/5dxtdwepmiko.png "")

steverugi

Hi @Nigel

I am keen to hear the forum members' thoughts on how timber framed, or metal framed walls will in-fill insulation is handled IFC wall material layers.
Here in Aotearoa NZ we typically build houses and smaller buildings using 'light timber framing' similar to parts of Australia and USA.
The question is what is good practice in IFC? ![]
thank you in advance :)

interesting topic!

I would gladly extend the request to other parts like: what's best IFC practice for foundations or floors, for instance, or when it comes to walls if plaster is together with blocks or separate covering layer instead..
I understand it depends on several factors but it would be useful to have an exchange on it I think

I can prepare an example of how I'd usually IFC the elements in my takeoff models

KoAra

Very interesting. I too would like to know good methods.
I would like to see you discuss insulation for pipes and ducts as well as walls.
The IFC in Wiki.OSArch states to use Material layer set if it is just walls. what about framed walls?
https://wiki.osarch.org/index.php?title=IFC_-_Industry_Foundation_Classes/IFC_materials
One of the IFC entities is IfcCovering.
https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcCovering.htm

tim

@Nigel said:
I am keen to hear the forum members' thoughts on how timber framed, or metal framed walls will in-fill insulation is handled IFC wall material layers.
Here in Aotearoa NZ we typically build houses and smaller buildings using 'light timber framing' similar to parts of Australia and USA.
The question is what is good practice in IFC? ![]
thank you in advance :)
(https://community.osarch.org/uploads/editor/4o/5dxtdwepmiko.png "")

For material layers I have only ever done one layer for "insulated timber/metal studs". When the wall continues beyond a part that requires insulation, I split the wall and continue it with a new wall with a layer for "timber/metal studs" (uninsulated).

tim

@steverugi said:
Hi @Nigel

I am keen to hear the forum members' thoughts on how timber framed, or metal framed walls will in-fill insulation is handled IFC wall material layers.
Here in Aotearoa NZ we typically build houses and smaller buildings using 'light timber framing' similar to parts of Australia and USA.
The question is what is good practice in IFC? ![]
thank you in advance :)

interesting topic!

I would gladly extend the request to other parts like: what's best IFC practice for foundations or floors, for instance, or when it comes to walls if plaster is together with blocks or separate covering layer instead..
I understand it depends on several factors but it would be useful to have an exchange on it I think

I can prepare an example of how I'd usually IFC the elements in my takeoff models

The approach you take can vary based on the project and construction methods. In my recent project, I utilized a method that distinguished between "wall types" and "covering types." A "wall type" could refer to a complete wall, including its coverings, or just the structural/framed part, excluding coverings. On the other hand, a "covering type" pertained to the finished covering including its fixing system.

For walls, I found it beneficial to separate coverings in the following situations:

1. Structurally Engineered Components: When a wall included a structurally engineered component, such as concrete or core-filled blockwork, separating the coverings allowed for a clear delineation between disciplines (this also relates to foundations). This approach helped avoid redundant documentation, reducing the risk of errors.

2. Height Differences: In cases where there was a required height difference, particularly in exterior situations, the "wall type" extended from slab to slab, while the "covering type" covered the slab edge and continued up multiple stories. This separation ensured that each component had the correct height, didn't conflict with the floor slabs, and ensured the exterior precisely aligned over multiple stories.
   

By conditionally separating "wall types" and "covering types" I was able to maintain a relatively condensed wall and covering schedule while being able to accurately cover a variety of conditions.

For floor, roof, and ceiling types, I used a similar conditional logic. Except, rather than needing to control the heights differently, I needed to control their extents on the horizontal plane differently.

steverugi

thanks @tim
I too use separation between wall core (an IfcWallType with concrete hollow or solid blocks) and plaster (IfcCoveringType, USERDEFINED = plaster), in my case I also lay the plaster on the internal face of the wall, going around projecting structural columns if present.
This also allows me to identify different plastering+finishing in a specific IfcCoveringType
Out of curiosity: what about blinding layer under foundation elements, IfcCovering? cheers

tim

I don't think it's a covering. What about IfcSlab, BASESLAB?

steverugi

Hi @tim :
How about screed (light concrete between structural and finish floor) IfcSlab or IfcCovering? I'd lean toward the latter (USERDEFINED = screed)
I'm surprised such construction feature hasn't been captured in Ifc (?), if not as a class at least as predefined type
thanks

tim

I’d lean towards a screed being the ‘fill’ component of the material layer set of an IfcCovering-FLOORING.

steverugi

thanks @timeandprice

I’d lean towards a screed being the ‘fill’ component of the material layer set of an IfcCovering-FLOORING.

Good, I almost got it right this time :D

Moult

I would agree with screed being a floor covering. It's also a bit of a funny one in that sometimes it's a bit hard to remove (I think?) if no bond breaker is used.

tim

I added a request:
https://github.com/IfcOpenShell/IfcOpenShell/issues/5044

Nigel

Thank you all for your insights. It became an interesting conversation. My original reason for asking is my quest of making a classifying and naming guidefor exporting ifc out of revit and archicad. This could clean up the "shambles of random' and produce clean spreadsheets exported from BBIM.

steverugi

@tim said:
I added a request:

Wouldn't plaster deserve a predefined term under IfcCovering as well?
And paint too, at least a combination of the two?
..or there is an explanation for their absence?

tim

I don't think it's the Ifc approach to match classifications with materials as you would end up duplicating information more than necessary.

That said, for Plaster or Wallboard, I did expect to see WALLLINING as a predefined type under IfcCovering. I see they are covered in IfcWall-ELEMENTEDWALL. However, this wouldn't suit all use cases. As an architect, I like to keep structurally engineered walls separate. This allows for a better workflow when updating structural information. For example, a combined exterior wall assembly could consist of:
IfcCovering-CLADDING | IfcWall-SOLIDWALL | IfcCovering-USERDEFINED: WALLLINING

I wonder why WALLLINING is not a predefined type?

KoAra

I was thinking that LoadBearing in Pset_SlabCommon or Pset_WallCommon would sort out the structure or something.

steverugi

@tim said:
I don't think it's the Ifc approach to match classifications with materials as you would end up duplicating information more than necessary.

That said, for Plaster or Wallboard, I did expect to see WALLLINING as a predefined type under IfcCovering. I see they are covered in IfcWall-ELEMENTEDWALL. However, this wouldn't suit all use cases. As an architect, I like to keep structurally engineered walls separate. This allows for a better workflow when updating structural information. For example, a combined exterior wall assembly could consist of:
IfcCovering-CLADDING | IfcWall-SOLIDWALL | IfcCovering-USERDEFINED: WALLLINING

I wonder why WALLLINING is not a predefined type?

I totally agree

one more thing..

In many parts of the world the sequence is very simple, with some little variation: paint | skimming | plaster |blockwork (hollow or solid concrete) |plaster| skimming | paint
the implementation of these layers into a single layerset is not always the best solution

• as @tim nicely showed above, outside plaster is often a covering spanning from ground to roof
• finishing might be different, especially in internal walls, and needs to be identified separately
• when walls and RC frame meet the covering layer goes around columns or beams

I like this exchange, we are getting somewhere :)

steverugi

Hi @tim
or anyone else who knows about it:
is there a spot available in the Psets where I can save the drawing nr of specific elements? (the one I used to model it, like a reference dwg)
or should I just create a custom pset? best practice please?
thanks

tim

I am not sure I follow. Can you give an example?

steverugi

@tim said:
I am not sure I follow. Can you give an example?

thanks for the quick reply
I receive 2D DWG of a project I convert to IFC model for quantity takeoff
sometimes the model is more than one part and each of them come with dedicated DWG
is there anywhere I can save the reference drawing in a pset of an element or a group of them?

tim

@tim said:
...for Plaster or Wallboard, I did expect to see WALLLINING as a predefined type under IfcCovering. I see they are covered in IfcWall-ELEMENTEDWALL. However, this wouldn't suit all use cases. As an architect, I like to keep structurally engineered walls separate. This allows for a better workflow when updating structural information. For example, a combined exterior wall assembly could consist of:
IfcCovering-CLADDING | IfcWall-SOLIDWALL | IfcCovering-USERDEFINED: WALLLINING

I wonder why WALLLINING is not a predefined type?

Does anyone have any thoughts or comments on why there is no PredefinedType for WALLLINING? I don't like that my workflow requires a user-defined wall covering type. What am I missing?

Moult

@steverugi that sounds like a custom pset.

@tim I've always used CLADDING for that.

steverugi

Thanks @Moult

@steverugi that sounds like a custom pset.

Yes I did that, but I find it a bit odd that docs reference is not available.
Especially in finishing and MEP components is quite useful (am I alone here?), but as you wrote a custom pset is the fix.

@tim I've always used CLADDING for that.

Me too :)
Cheers

Nigel

Hi again, I have been reviewing an IFC4 that is part of a pilot project, where we are trying 'JIT' (Just In Time) and a client procured/supplied to site idea for housing projects. Anyway, I have two questions, 1. I am looking for some 'plain English' description of what to add as attributes (see PNG. 2. for a mech fixing what would be a Predefined Type? Also, there are two different 'Predefined Types' one for class and the second for attributes, is this a little confusing? I am looking forward the your interesting responses ;)

steverugi

Hi @Nigel

Hi again, I have been reviewing an IFC4 that is part of a pilot project, where we are trying 'JIT' (Just In Time) and a client procured/supplied to site idea for housing projects. Anyway, I have two questions, 1. I am looking for some 'plain English' description of what to add as attributes (see PNG. 2. for a mech fixing what would be a Predefined Type? Also, there are two different 'Predefined Types' one for class and the second for attributes, is this a little confusing? I am looking forward the your interesting responses ;)

I can't find the .png attached ;)

Nigel

@steverugi I forgot! haha

steverugi

2. I would be happy with the 'How it should be' solution, is there some info you need to add?
3. double predefined type I think is related to the UI, it has been removed for other classes (check IfcWall for instance) since the predefined value of an instance is inherited from its type

Nigel

@steverugi thank you, how do you think I should define the type of content for 'Object Type'?

steverugi

@Nigel said:
@steverugi thank you, how do you think I should define the type of content for 'Object Type'?

'ObjectType' is used when USERDEFINED is selected, to indicate its value if the other predefined values do not meet your requirement, but I see 'SCREW' is what you need (part of the prefefined list) so 'ObjectType' should be left empty
But I'm curious to know by the experts if the above is correct :>))

steverugi

Assign document to entities

I receive 2D DWG of a project I convert to IFC model for quantity takeoff
sometimes the model is more than one part and each of them come with dedicated DWG
is there anywhere I can save the reference drawing in a pset of an element or a group of them?

I think I found an alternative way compared to custom Pset:

prepare document references

Project Overview > Project Setup > Documents

click on the + icon to create a new main document reference container (or folder), like 'drawings'

from there you can edit the folder properties clicking on the pencil

and fill the fields as required to add information to the reference document folder

click on the V icon to save them, now click on the arrow > to the left to start loading documents in the folder

from here there are three options:

1. add a subfolder with relevant documents
2. add a document reference to the current folder
3. edit the properties of the selected document reference, click V when done:

assign document reference to element

1. select the element
2. go to Object Information > Misc. > Documents > click on + Assign Document References, then select the folder, and click on the arrow > to the left of the document icon :

select the desired reference (in this case there is only one) by clicking on the + icon to assign the document refrence to the element

now properly assigned:

the procedure is not that different than the classification assignment

nice one! many thanks

tim

@Moult said:
@steverugi that sounds like a custom pset.

@tim I've always used CLADDING for that.

Thank you! I was thinking of CLADDING as an external element, but I see there is a PSet to nominate IsExternal