Wall composite/construction layers . Different methods, different benefits and problems.

[Vincent G_]

Hi everyone

This is not a brand new topic, a lot has been told about it already, but I've not found yet a satisfying solution.
I'm going to give a specific example that I think illustrate perfectly the issue and struggle I'm having (I reckon many have).

So we got our scope from ID team today, and we got to add tiles to some walls in the project's lobby. We're working on a SDA residential project (high disability) so clearances are absolutely vital. Hence, we can't just add a surface to the wall and tag it, we need to take into account the tile thickness, skirting thickness, and probably even the glue to fix the tiles on the wall.

We're trying to work as BIM as possible on this project since I'm tired of this half BIM half autocad mentality that make us re-do everything 10 time (tagging, schedule, annotation ..... long list).

My problem is the following: I've defined wall types based on all requirements we had to comply with (fire, acoustic, impact resistant, Rvalue...) and set composite from them. A lot of the workflow is based on this principle: for instance wall type labels are reading and display the composite name so if the wall change we just swap the composite and all's auto-updated. It works very well until you need to add a finish that has a non negligible thickness (other than paint finish pretty much).

We got the same wall type on different location, on one location (entry lobby), we need to add tiles on it while the rest is just a paint finish.

Here are the different option I can think of with everything I've read on the topic, and none is really satisfying.


01. I create instances of my base composite, the only difference being the surface finish (tile, timber, any finish with thickness vs paint). So if my typical wall is a 144mm thick party wall IDed as W35, I'll need one variation of the composite per finish type (I need instances only when thickness is added to it), meaning I end up with a bunch of very similar variation of the same type like:
PW_(144)_2x13SPB/92ST/2x13SPB_W35 = The base composite with paint finish
PW_(154)_2x13SPB/92ST/2x13SPB/10TL_W35.1 = The same wall but with tiles on one side
PW_(174)_2x13SPB/92ST/2x13SPB/30BT_W35.2 = The same wall with timber cladding
...
This become dangerous and hard to maintain, and in certain case we'd end up with a lot of variations. Also keep in mind that this corridor wall is a party wall, hence got structural columns inside so the wall is not one element from start to end, but a series of composites. Imagine if each piece need instances: nightmare.
Not to mention how confusing and long schedules might become.. And if we need to change something in the original wall (i.e insulation type or thickness) it means you need to update every instance. Open door for errors as I'm sure we'll always miss a couple of instance + the time it take to report one single change to every instance.


02. Adding a 10mm wall as the tile layer. That solution is a good one for specific locations such as a layer of tiles in the kitchen above the counter or in bathrooms.

But on the case of my lobby wall, it means adding wall empty openings to match with all my doors / service doors or have a lot of pieces to cover the part of the wall that will in fact hold tiles. Both are disaster to maintain.


03. Similar to above, I often heard people advising not to work with composites but with basic walls layers meaning that instead of having a composite wall for instance blockwork + plasterboard, you got one simple blockwork wall and one basic plasterboard wall (usually they separate lining from "structure"). This kind of make sense in some cases such as facade walls where each layer might not have the same extend (plasterboard goes to ceiling but insulation to under the slab and external cladding above slab), but same issues as above.. if you got openings, how you deal with? a series of empty opening for each layer? and try your best to have the right extend/offset of the frame that you need to manually adjust every time your wall change? And if you need to change the wall position / extend you got to do it for each layer and end up with non perfectly aligned pieces? No, thank you. Maybe in late CD but still not ideal.

04. Using complex profile. I've not explored this idea yet, my workmate suggested it to me this evening but I can already see a few major problems with that. You need 1 profile per height, so if you got several heights, you need several profiles. Again, that creates more problems and maintenance than it helps. Also all the systems based on the fact that the wall is a composite wall are broken (all wall ID tags reading composite name).

05. Change the wall type system, and have one type per finish. Well, so if you got the exact same wall but change only the paint finish color you need one type for each? Like family in revit? But without family system. And if each side of the wall got a different finish, more types? And what if the wall got two different paint finish on a certain extend (from 0 to +500mm blue, and +500 to ceiling green)? Not ideal either.

I'm sure you guys came across the same problem, and I'd be glad to ear what's the best/less annoying method to deal with it.

I really do hope there are some tricks I've not think of! Please surprise me!

[Vincent G_]

Erwin wrote:
If we were to model this as part of composite/complex profile we run in to problems with classification and it starts becoming a pain in the behind to properly dimension things before finishes are applied (which the contractor would like to know).

For these two reasons we would model it seperately, if needed. I can recommend putting the finishes on seperate layers with their own unique intersection number. This way you avoid unwanted wall connections.

We typically do not model plaster finishes, since the thickness will vary. For quantity take off for price estimates we need m² anyways, so to model the thickness is of little importance to us.

It gets a bit fiddly with doors, as pointed out, but for tile or wood finishes it can be worth it. For some renovation projects we do sometimes model the plaster, when it is covering old brickwork, for example.

For quantity take off, zones offer a lot of options too, but this might be tied to the local version of our zone stamps that are part of the Dutch subscription library.

Properties are very powerful as well for scheduling purposes.

That's what I did end up doing for these tile finish. I agree the method is the best we have now to make sure all's BIM and quantified. The goodie is great for skirting and corniche tho as it is associated to the wall (move with the wall) and read all openings so you don't need to maintain these. Once I got my GDL skills upgraded i'll try to code an object based on that goodie in term of functionality (associated to the wall, reading openings) but that also allow the texture alignment and the use of material/surface. This way we could schedule it exactly as you do for the finishes with a wall! I'll be happy to share that when I find the time to get it done!

kmitotk wrote:
Great.

Problem is that the extend of zones depend from one place to another depending of the methods of calculation, and here in Melb they usually extend to external face of the walls or mid-wall for party walls.

Zones normally extend to the mid-wall here in Japan as well, but rarely to the outer face though. When you place a zone, don't draw it manually but always use the reference line based method. The magic wand should pick up the wall outlines instead of the wall reference lines and the zone area calc will be based on the wall reference lines. And in case some of the surrounding walls can't intersect with one another and the zone won't detect the enclosed area, use a polyline to connect the wall ends to close the gap. Make a separate layer for the polyline so you can hide them on the floor plan. Hope it helps.

Good to know that trick indeed. It seems that in Australia they have different ways of calculating GFAs NSA/NLA, sometime internal face, sometime external face of the walls, and mid wall for party walls.. But with a bit of workaround I'm sure we can get the same workflow! Thanks for sharing the trick mate.