# Engineer stamp I-Joist floor design



## Buelligan (Jan 31, 2019)

How do you guys handle I-Joist floor designs? Do you require all systems to be stamped by design professional? Do you allow complete designs by the charts provided by the manufacturer as long as all the members follow the chart (i.e. uniform top load only) How do you handle designs that fall outside of the manufacturer's standard design specs. We have a contractor trying to get out of stamped plans with a form letter from a manufacturer. We feel it just gets the manufacturer out of liability but does not satisfy the stamped design requirements for all floor systems we currently use.


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## steveray (Jan 31, 2019)

Sounds like you are on the right track.....


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## Sifu (Jan 31, 2019)

I have accepted a prescriptive plan (prescribed by the manufacturers software), but it must be provided by the manufacturer, and have all details.  That being said I don't see them very often without the seal.


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## Pcinspector1 (Jan 31, 2019)

I would Treat it the same way you would for roof trusses but you need the floor layout first, a deferred submittal might be to late. Should have this info when doing the plan review.


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## fatboy (Jan 31, 2019)

Follow manufacturer's specifications exactly, or provide stamped engineer's plans


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## classicT (Jan 31, 2019)

Accept the prescriptive plan when the house is designed per IRC and the floor design follows manufacturers installation guide or manufacturers joist calc's are provided.

When the house is designed by an engineer per the IBC (lateral and gravity only), we require the EoR to stamp the layout with his/her shop drawing review stamp. Same principal as truss layout.


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## jar546 (Jan 31, 2019)

fatboy said:


> Follow manufacturer's specifications exactly, or provide stamped engineer's plans



When you say "followr manufacturer's specifications exactly,..." does that mean that they follow the layout specific to their installation provided by the manufacturer?


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## fatboy (Feb 1, 2019)

Installation details, spams, blocking, penetrations, etc., not necessarily a layout. I don't know that manufacturers even do that, can't say I have seen one.


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## tmurray (Feb 1, 2019)

For floor systems, we ask the supplier for a layout. We will check the layout against the manufacturers tables if we have any concerns. 

For roof trusses, we ask for a layout. At the framing inspection they have to have the stamped truss drawings on site so we can verify all the bracing is in.


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## Pcinspector1 (Feb 1, 2019)

tmurray said:


> For floor systems, we ask the supplier for a layout. We will check the layout against the manufacturers tables if we have any concerns.
> 
> For roof trusses, we ask for a layout. At the framing inspection they have to have the stamped truss drawings on site so we can verify all the bracing is in.



We do it here the same way, with the exception the contractor can provide the floor layout from the supplier (lumberyard) or manufacture. We typically do not deal with suppliers, make the contractor deal with them. I have called the truss guys on occasion, very helpful when I have Q's.


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## tmurray (Feb 1, 2019)

Pcinspector1 said:


> We do it here the same way, with the exception the contractor can provide the floor layout from the supplier (lumberyard) or manufacture. We typically do not deal with suppliers, make the contractor deal with them. I have called the truss guys on occasion, very helpful when I have Q's.


We only have two different suppliers for floor systems and they are the truss manufacturers, so it makes it really easy.

I think I've only seen three houses with nominal lumber floor systems in the 8 years I've been here.


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## Mark K (Feb 1, 2019)

If in your state the state licensing board for engineers and architects would require that the  design be performed by an engineer or architect  the contractor cannot be allowed to perform the design


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## fatboy (Feb 1, 2019)

Mark K said:


> If in your state the state licensing board for engineers and architects would require that the  design be performed by an engineer or architect  the contractor cannot be allowed to perform the design



Colorado does.

Does that mean I have to have an electrical engineer to wire a house?

Plumbing engineer to install a toilet?

These are designed, engineered, tested and listed products, why would I need an engineer to design a floor system that is already engineered?


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## Mark K (Feb 2, 2019)

States typically provide exemptions for certain types of projects.  For example in California an electrical contractor is allowed to design the electrical system for projects where the contractor in installing the work.

Also in California the structural system of certain types of residential buildings are not required to be designed by an architect or civil engineer.  But if you do not satisfy  that criteria then the work needs to be designed by a registered civil engineer or architect.  It would not surprise me to find that the exemption in state law does not apply to I joists.

I am not familiar with the licensing laws in Colorado but I would expect that there are similar provisions in your state laws.

I joists are not required to be listed.  There is a standard that defines the testing protocol used to define the allowable design values for the joists.  These design values are then used to design the specific joist 

While the design aids provided by the I joist manufacture are useful they do not necessarily consider all the conditions specific to the project. In addition, check if the manufacture provided designs specific to the particular project that are stamped and sealed by an engineer licensed in your state.  If not they will decline responsibility for the  design.

Licensing law is separate from building code law and what the building department enforces must be compatible with state licensing law.


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## fatboy (Feb 2, 2019)

Well, for 22 years, I have been allowing engineered joist/beam systems to be installed w/o a stamp, when complying with manufacturers specs.


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## Mark K (Feb 2, 2019)

My point is that  what is required to be stamped is governed by the state professional licensing laws.  What you have been doing does not change this fact.  Check what are the laws in your state.


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## fatboy (Feb 2, 2019)

I disagree, I don't think state licensing laws have anything to do with it, this is already an engineered system, tested, done. I don't need another engineer to tell me it is OK. Follow manufacturers specs..... we are good.


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## rogerpa (Feb 3, 2019)

Already recognized by the code.
R502.1.2 Prefabricated wood I-joists.
Structural capacities and design provisions for prefabricated wood I-joists shall be established and monitored in
accordance with ASTM D 5055.
Do you require an engineers stamp for a sawn lumber floor joist system?


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## Mark K (Feb 3, 2019)

In California all buildings must be designed by a registered engineer or architect unless there is an exemption.  The primary exception is that single family and multiple family buildings containing no more than 4 dwelling units which are no more than 2 stories tall and that conform to what is conventional construction do not require an engineer or architect.  Thus the answer to the question is yes for other residential buildings and all commercial buildings.

While the definition of conventional construction has gotten less well defined over the years originally this limited this exemption to relatively simple structures using traditional materials.

All ASTM D 5055 does is establish the allowable capacities of the individual joist units.  This does not establish every thing that must be done to resist building loads.  I Joists are not as forgiving as sawn lumber.

As I  have said what defines when an engineer's or architect's stamp is required is governed by state licensing laws, not by what is in the building code or what the building official is comfortable with.


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## tmurray (Feb 4, 2019)

These products are engineered. At some point an engineer stamped off on that span table. Having an engineer stamp off on a layout that simply follows the span table is redundant.


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## Mark K (Feb 4, 2019)

You assume that an engineer stamped off on the span table.  Do you have a span table that was stamped and signed by an engineer licensed in the state where the project is located?

What is important is that somebody needs to look not just at whether the member has the proper strength but also at the load transfer into and out of the joist as well as the appropriateness of the layout of the structural system.

I suspect that much of the pushback from what I am saying comes from individuals who are not trained as engineers and thus lack an awareness of the bigger picture.


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## Pcinspector1 (Feb 4, 2019)

Here's what happen in our area: 
Back in the old days we switched to TrusJoist, a Weyerhaeuser Company. They took our floor plans, did the FJ lay-outs, stamped them and we ran down to the permit office and got our building permits. 

The lumberyard we used stocked the joist and components with the lengths we needed. The manufacture starting coming out with more products, like studs, LVL, Parallams, Timberstrand. Microlams, rim board, stair treads and so on, all great products. We had to educate ourselves on the use of these products and GO TO CLASS! Now the yards just send it out like 2X lumber, and there is supporting data and span charts provided by the manufactures. So I think we have taken the manufactures engineers out of the floor design business. Do we still look at these items as engineered products, like trusses?

Some of your states require One and Two Family plans to be stamped, there's the issue, IMO?


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