TMS 402-22 Masonry Veneer Support on Wood Construction?

[dfus]

In TMS 402-16, sections 12.2.2.3.1.2 and 12.2.2.3.2 (sorry, dyslexics) limit the height of masonry veneer supported on wood to 12 ft, and require lintels over openings to be supported by non-combustible framing where the veneer isn't self-supporting. I point to these provisions semi-often to get architects to let me have a couple steel posts and a tube header, but since the veneer chapter re-write in the 2022 code, I don't see this addressed anywhere.

Am I overlooking it? If not, why would this restriction have been removed?

Thanks, and if this has been addressed somewhere already, I apologize. I couldn't find a relevant thread.

 

[masonrygeek]

I want to be careful when discussing this topic since it matters whether you say "supported on" wood construction or "supported by" wood construction. It seems like you are talking about an application of brick veneer being supported on top of wood construction (even if the actual bearing material is a steel angle). There are few instances of brick being supported on wood construction such as a wood foundation, but there may be more examples of brick veneer being supported by a steel angle which in turn is connected to wood framing (e.g. shelf angle attached to a rim joist). In that case TMS 402-2022 Section 12.1.2.3 talks about deflection limits for the support which requires l/600. That may end up limiting the height of the brick veneer based on the loads. The other part of this is the differential movement which is covered in TMS 402-2022 Section 13.1.2.2.2. In that section it limits brick veneer to 30' (38' at gable), but a designer can put more restrictive limits if movement calculations require a shorter height. So, the 2022 code took out some of the "easy language" and made designers provide calculations to limit brick veneer heights.

And remember, this discussion does not talk about the lateral support ("supported by") and the deflection requirements of the wall. The 2022 code changes things again and uses a stability analysis and a table to justify that.

 

[dfus]

The other part of this is the differential movement which is covered in TMS 402-2022 Section 13.1.2.2.2. In that section it limits brick veneer to 30' (38' at gable), but a designer can put more restrictive limits if movement calculations require a shorter height. So, the 2022 code took out some of the "easy language" and made designers provide calculations to limit brick veneer heights.

This makes sense to me. Thanks for the response! I think you're saying they eased the code restriction back and let the engineer be responsible for considering the differential movement instead of the code imposing a low limit.

However, what is still confusing to me is the removal of this section:



The situation that prompted me to go looking for this in 2022 was an exterior wood-framed canopy up against a veneered gable wall. The architect had drawn the brick sitting atop the canopy roof framing and over an exit:



I always read the above section as meaning "don't support veneer on combustible framing over an opening b/c fire safety." That section is now gone, and I wish it wasn't/wonder why it was removed.

 

[masonrygeek]

Of course, the easy answer to this is - don't support the masonry veneer on the wood at all and let the canopy be self-supporting. I do feel that in the past, supporting brick on wood in any way would be a cause for concern from a fire standpoint. That mentality isn't as evident today, not sure why, and not shared the same as everyone.

 

[dfus]

Right on, I don't intend to, code provision or not. The fire issue scares me a little too much.

That mentality isn't as evident today, not sure why, and not shared the same as everyone.

I would hope removing that code provision (which only implies the concern to begin with) doesn't kick that can further down the wrong road.

Thanks for the response!