How does an architect compare assemblies

I am an architect. How do I go about a comparison between two (or more) wall assemblies? We are looking for low carbon solutions for a facade and are studying options - like the ones listed below.

How do I go about this? It’s an early design stage so it does not need to be 100% accurate, just enough to give a sense of the relative CO2e/m2.

Would EC3 be able to do this? Would the information all be there?
Or should we be looking at another tool (Tally, Cove, OneClick, etc.).
I’m not looking to become an LCA professional, I just want to provide our firm the capability to lead early design decisions.

An example of 3 options:

Precast Concrete

  • 200mm Precast Concrete
  • 215mm Closed Cell Spray Foam Insulation
  • 152mm Steel Studs at 400 o.c.
  • 13mm Gypsum Board

Cementitious Panels

  • 10mm Cementitious Panels
  • Gasket
  • 30mm Air Space
  • Vapour Permeable Moisture Barrier
  • Horizontal Z-girts
  • T150 Thermal Spacers
  • 150mm Semi-rigid Insulation
  • Vapour-permeable self-adhered membrane
  • 13mm Fibreglass Faced Exterior Gypsum Board Sheathing
  • 152mm Engineered Steel Studs
  • 100mm Closed Cell Spray Foam Insulation
  • 13mm Gypsum Board

Metal Panels

  • 38mm Composite Metal Panels
  • 25mm Air Space
  • Horizontal Z-girts
  • Thermal Spacers
  • 150mm Semi-rigid Mineral Wool Insulation
  • Vapour-permeable self-adhered membrane
  • 13mm Fibreglass Faced Exterior Gypsum Board Sheathing
  • 152mm Engineered Steel Studs at 400 o.c.
  • 100mm Closed Cell Spray Foam Insulation
  • 13mm Gypsum Board

Hi Lloyd,

I think there are a few potential resources that you could utilize since you just want a comparison and not necessarily a full LCA on the wall assemblies. These are all free tools.

  1. Payette’s Kaleidoscope tool: Kaleidoscope: Embodied Carbon Design Tool - Payette
    This will compare pre-loaded options for facades in the “envelopes” tab. They include some of the facade types you are comparing, but won’t cover the entire assembly.

    This is a Google Sheet - based estimator. You can choose to only fill in the sheets you want to use (such as the “Exterior Walls” sheet in this case). You would be able to select more of the assemblies than using Kaleidoscope and you could have 3 different versions to compare in the “Results” tab.

  3. EC3 would definitely work as well. Just slightly more time consuming than BEAM, but would also be more specific since you could select manufacturer EPDs and not be limited to generic ones (which I believe is where BEAM gets its data).

I believe OneClick has some options to do a comparison like this as well, but it also comes with a high price tag.

I would be curious to hear what you end up using and any tips you have as this comes up in our work as well. Always nice to hear how others are tackling assembly comparisons!

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Hi Lloyd and Megan,

Quick update re: BEAM data: We use both product-specific and industry-average EPD data wherever possible. We also provide non-3rd party verified EPDs and LCA analysis for products that otherwise have no verified EPDs. In product categories where there are only product-specific EPDs, we provide an average of those products for users looking to model average data (e.g. early-phase analysis prior to identifying a particular product). In all cases, we disclose the type of data for each product in the title/formatting, as well as a master list of all data sources in the tool. Be in touch if you have any further questions about the tool!

Jacob Racusin
Builders for Climate Action

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Hi Jacob,
Thank you for clarifying! That’s all good to know.

Thank you both for a very useful answer. I’ll test them all and let you know how it goes.


One more note: we are on the verge of releasing the next version of BEAM (due out end of the month, if all goes to schedule), so if you test it now, swing back through in a couple/few weeks and you’ll find many improvements.

Best of luck,


Hi Lloyd,

You might find a recent study by RDH and TMU answers the questions you have. New Design Resources for Embodied Carbon Targets - Blog - RDH Building Science

Happy to discuss if you need to bounce ideas off someone - especially if you are interested in digging in to the embodied carbon vs. operational carbon differences of these assemblies.



What a fantastic resource, well done to RDH! Thank you for sharing that Forest.

I’ll go through it and see what I can use… and I may just take you up on your offer. :slight_smile:

Hi Lloyd - a bit late to the discussion, but we have been doing ‘optioneering’ like this in Preoptima CONCEPT. There’s a number of pre-built facades that can be modified. We currently have a free license available.

Happy to share more if you’d like as we are continuing to build this functionality up - I’d appreciate your feedback too on how we are currently approaching it.

Thank you Jay, I’ll definitely take a look.