Deck post sizing code evolution

[Glenn]

Deck support posts weren't addressed until the 2015 IRC. I am very involved with the creation of deck codes, including these. I will be testifying for (and against) deck proposals next week for the 2021 IRC. Here is an article I just wrote that explains the evolution of these provisions from 2015, 2018 and 2021 proposed. Enjoy!
https://www.deckmagazine.com/design-construction/framing/new-height-limits-for-deck-posts_o

 

[ADAguy]

Need to bring Simpson into this conversation.

 

[Mr. Inspector]

Most of the new houses I see have porches with roofs. There is nothing about porches in the code.
Could a added column be added to the tables for if a roof was built on the deck/porch with the roof posts directly above the deck posts? It would add some dead loads but most of the snow load would be on the roof.

 

[jar546]

Most of the new houses I see have porches with roofs. There is nothing about porches in the code.
Could a added column be added to the tables for if a roof was built on the deck/porch with the roof posts directly above the deck posts? It would add some dead loads but most of the snow load would be on the roof.

This is a common problem with areas that have snow loads. If the piers are built to the minimums to cover the soil capacity and then you add both the dead load and the snow load to those piers, your piers are no longer compliant. I saw this time and time again in PA where contractors submitted proposals to add a roof over the deck at which point they were asked to show compliance with the loading of the piers. 100% of the time they were not big enough. I see code officials passing this stuff all the time in PA which shows how clueless the industry is.

 

[classicT]

This is a common problem with areas that have snow loads. If the piers are built to the minimums to cover the soil capacity and then you add both the dead load and the snow load to those piers, your piers are no longer compliant. I saw this time and time again in PA where contractors submitted proposals to add a roof over the deck at which point they were asked to show compliance with the loading of the piers. 100% of the time they were not big enough. I see code officials passing this stuff all the time in PA which shows how clueless the industry is.

I'll second this and add that the issue is prevalent at the connection of the proposed deck/patio cover to the existing structure as well.

Could not count the number of times an existing header fails or the capacity of the existing footing is exceeded. As a whole, the industry needs to be more aware that additions will typically require modification of the common (shared) elements.

 

[Glenn]

Need to bring Simpson into this conversation.

They have been. I have been working with the Deck Code Coalition since 2013. Simpson is a big contributor to our collaboration...actually many in the group are. The coalition is incredibly diverse. Any proposal for 2021 coming from the Deck Code Coalition are probably some of the most well-vetted and collaborated proposals you can find.

 

[Glenn]

Most of the new houses I see have porches with roofs. There is nothing about porches in the code.
Could a added column be added to the tables for if a roof was built on the deck/porch with the roof posts directly above the deck posts? It would add some dead loads but most of the snow load would be on the roof.

Slow progress. Porches are certainly on the game plan for future code development. 2015 did bring in a new table for porch roof beams, but it is very simple and thus limited. See Table R602.7(3)

 

[Glenn]

This is a common problem with areas that have snow loads. If the piers are built to the minimums to cover the soil capacity and then you add both the dead load and the snow load to those piers, your piers are no longer compliant. I saw this time and time again in PA where contractors submitted proposals to add a roof over the deck at which point they were asked to show compliance with the loading of the piers. 100% of the time they were not big enough. I see code officials passing this stuff all the time in PA which shows how clueless the industry is.

We have also submitted a new footing table. Like this post table, it is based on tributary area and snow loads of 50, 60, and 70 psf.

 

[jar546]

We have also submitted a new footing table. Like this post table, it is based on tributary area and snow loads of 50, 60, and 70 psf.

Yeah, now that is what I'm talking about.

 

[ADAguy]

Spot on, keep it up.