Thin Veneer and Exterior Rigid Insulation (Yin and Yang)

Question Icon
Posted by: from Ottawa
9/5/2022 at 10:45:52 PM

Hello everyone!

First off, thank you kindly for taking the time to review my question, it's great that resources like this exist!

I have been doing an architectural drawing set- (a moderately-accurate set for pricing and to exceed the City's drawing requirements) which has led me to some fun detailing exercises.

I have come across a sill detail that I don't.. quite know what would be best to specify.

Allow me to (try and) explain: Essentially I have a compound wall type that would be a stone cladding from the top of foundation, up 42", then a coping sill piece and finally a conventional vented board and batten up until the eave (I'm *attempting* a craftsman look).

Usually when I deal with brick over stone, I find a mechanical tie to the structural sheathing is sufficient (with blocking in the studs, of course), but in the case of a thin veneer, it is a sealed wall system which is quite.. heavy once you get all the mortar in place.

I have done some readings (notably from "Masonal Stone, Inc.'s Technical Guide" (Endorsed by Picco Engineering) and they do not particularly support a "thin set" veneer on any form of exterior insulation due to its' lack of compressive characteristics.

This is understandable, but difficult to surmount because where my subject property is in Ottawa, ON, (HDD=4500, SB-12, Package A4 ~92%+ AFUE) where an R-5 exterior board insulation is required. I'm also not too cozy with the idea of sealing a wall as I've always been taught that breathing walls are usually better.

I have managed to coerce my client into considering a full-depth, mechanically-tied stone veneer to simplify this challenge, but I am wondering if anyone here has run into this sort of wall system before? Is there perhaps a more dense exterior insulation that can withstand the weight and movement of a heavier (stiffer) thin set veneer?

I hope this question wasn't too long-winded and isn't completely hidden in plain sight. If you require any further details about this project, I'd be happy to share!

Thank you kindly for taking the time to read through this and for considering helping an overwhelmed junior architectural technologist out!

Kind regards,


P.S: The most applicable technical guide that i sorted through (Masonal Stone, Inc.) can be found here:

I also found a great library of (US-based) knowledge is here.. but they don't seem to address exterior insulation as much- (Probably warmer over there!):

User Icon
Date/Time9/6/2022 at 3:36:51 PM

Personally I think you answered your own question. Its fun to think outside the box but alot of times at the end of the day there is only one right way to do it. The mechanical tied veneer you propose to client is what I would have gone with. I can't think of any other option that is "easier" or guaranteed to work. Lots of new products coming out everyday but I find most of them untested long-term or just plain garbage.

User Icon
Richard in Edmonton
Date/Time9/6/2022 at 1:25:31 PM

In Alberta thin brick veneer is not described in the Building Code; therefore each installation requires 'engineering'. There is also a now discontinued 'Standata (19-BCV-R1)' which is a pre-engineered system with restrictions on height. The Standata does not describe installation over exterior insulation; to do so may require sheathing over the insulation, attached through to the studs and the expanded metal lath also attached through to the studs. I previously contacted the author of the Standata and found him willing to assist with technical issues. You are correct with your concerns about a wall system that does not breathe. A possible solution is HAL-TEX COR PLY or similar provided it is acceptable in your region.

User Icon
Cory in Ottawa
Date/Time9/7/2022 at 12:24:57 PM

Hello everyone,

Thank you both for your excellent replies- it is reassuring to know that I'm not the only one reluctant to employ such a strange system.

I have tracked down a supplier who does full-depth stone which match the aesthetic I'm hoping to achieve (thank god for Permacon!)

I know it'll be a bit more expensive, labour-wise and heavier, but from an envelope perspective, it'll outlast the previously mentioned. My main concern was hygric buffering between the stone, its' mortar and the substrate- paired with the fact that I'd probably have to use a crazy-dense insulation board that can handle the rotational forces a deflecting wall might inflict, it would probably end up being as expensive at the end of the day, without the surety that the wall would last.

Plus I'm only using stone rendering for the first 42" of the wall, so hopefully that reduces some burden to the builder.

I will do some digging into the resources you've provided me just for my own knowledge as I quit enjoy learning new things (one of the most attractive parts of our field, and being a "sort of" jack-of-all trades.

Thank you so much again, and all the best!


User Icon
Richard in Edmonton
Date/Time9/7/2022 at 2:29:09 PM

Glad to help. I would be comfortable using the product for the low height of your application provided the installers were well qualified and the details were well described. My previous involvement was investigating failures in two newer buildings where the stones were falling off at greater heights (2 stories). Cause of failure was improper application procedures, primarily poor mortar mix and not back-buttering the stones together with poor flashing detailing resulting in water entry.

Search the TrustedPros directory and discover the best contractors in your area.

Find your home service pro
Great renovations start with a great contractor.

Since 2004, TrustedPros has been helping homeowners find the right contractor for their home improvements and repairs.

Post Your Project

Within hours you'll be comparing offers from top-rated professionals. It's free to post and you're under no obligation to hire.

Trustedpros Inc. does not warrant the accuracy, completeness, safety, legality or usefulness of any Content, or Whether Content is Current and up-to-date, and TrustedPros Inc. Shall have no liability whatsoever with respect to your use or reliance upon any content or for content being removed or otherwise ceasing to be available. Please refer to the terms and conditions of use of this websites for more details.

Get quotes from top-rated contractors