Define "Truss Alteration"

Wondering your opinions.

1: Is a platform nailed to the top of trusses for support of a HVAC system or water heater a “truss alteration”?

2: Is a trayed ceiling nailed to the bottom of trusses a “truss alteration”?

If you saw either (and you probably do often), would you call it out as in need of further evaluation by the truss manufacturer or a professional engineer?


No also

Only if I seen them use lag bolts through areas reducing the strength of the trusses in question. The movement and vibration may be enough to break in attachment area, but I would not call it a truss alteration per say.:smiley:

Yes it is and a design engineer should approve the extra load added either on top or bottom of the truss.

IRC 2012
R502.11.3 Alterations to trusses.
Truss members and components shall not be cut, notched, spliced or otherwise altered in any way without the approval of a registered design professional. Alterations resulting in the addition of load (e.g., HVAC equipment, water heater etc.), that exceed the design load for the truss, shall not be permitted without verification that the truss is capable of supporting the additional loading.

Commentary: Addition of loads in excess of the design load is allowed only if the additional capacity of the truss can be verified. Also see the commentary to section R502.8.2

Now, having said that, I believe it will depend on the house.
If it’s an older house and I see that the addition looked recent, then I would definitely write it up, since the design of the truss system most likely was not made for the extra load.
If it’s a new construction and I can see the plans or I see that the section of the truss over which the HVAC platform is, was reinforced or had a different truss design, then no, I would most likely not write it up, since at that point, the original design of the roof was intended to receive that extra load.


As stated any load that was not part of the original truss design would be classified as an alteration. I would not typically make a big issue of a HVAC system it unless there was physical alteration or damage to the truss or I see unusual displacement of the loaded truss member. However water heaters are much heaver than the average HVAC system. I have never seen a water heater suspended from a truss or rafter but have seen several supported on the ceiling joist and bottom chord of trusses. I would call these out only if there was no support wall under the water heater.

Exactly how I see it. Technically nailing a wind brace or lateral bracing to a truss, or even stapling a Romex cable to it, would be an ‘alteration’ I suppose, but that doesn’t mean it is in need of further evaluation by an engineer.

In new construction, as a Building Official, I see truss design documents and require the builder to demonstrate that the trusses can support the equipment loads. We as home inspectors don’t have access to those documents however.

Nailing a platform to a truss is not something I call out as a defect because the system has usually been there since the house was built and was passed by code officials with access to truss design documents.

Another home inspector I know recently called it out as in need of further evaluation and it was a house I inspected for my client previously (who is now the seller). My ex-client has asked me to explain why he called it out and I didn’t.

Things might have changed since the time you inspected it Joe.

Modifications could have been made. :slight_smile:

I have seen many and pointed out many defects on old and new homes which were “passed” by code officials. So have you :wink:
And as I said, it would be on case by case. If the platform looked recent, I could call it out in a heart beat. If it looked original, I wouldn’t worry about it unless I saw stressed signs.

So, would you qualify this inspector as thorough, just picky or foolish?
What was your answer to your ex-client?

Who is the builder?
A Pulte homes employee told me several years ago that their engineer sent a home inspector we both know a letter explaining that the extra height added to the lower chord to accomodate R30 insulation under the attic platform was an accepted field practice. These houses also typically have interior walls near the HVAC and water heater loads so common sense can prevail unless the inspector was hired to do a technically exhaustive investigation. If he called it out for just needing further evaluation then no problem was actually found right? If the house is still under the builders structural warranty they can give the sellers a letter.

[FONT=Arial]I know Mr. X well. He is a friend of mine. He is a very good and respected home inspector. I am aware that he always calls out attic equipment decks in his reports as a “truss modification”, but our opinions differ on this subject. Apparently few if any Building Officials and code enforcement officers agree with Mr. X’s recommendation for the need for an engineer’s evaluation of a truss roof system when an equipment deck is built on top of it. It is extremely common to have an elevated platform on top of trusses. The reason the 2x4 platform was built was to comply with the code requirement for having R30 levels of insulation in the attic. With a deck directly on top of the trusses, the insulation wouldn’t have the depth necessary to meet R30. Thus, many, many builders attach a 2x4 elevated platform to the trusses to give the platform the extra height to maintain the insulation requirements. Is it technically a “truss alteration”? Yes. Nailing OSB decking directly to the decking would also technically be an alteration I suppose. Wind braces are also nailed to trusses and lateral supports are nailed to trusses and Mr. X does not call that out as an alteration in need of an engineer’s evaluation. Therefore, it is not something I ‘missed’, but rather something I chose not to call out as a defect or in need of further evaluation. The code officials pass it every day. Indeed, I am a licensed Building Official in SC and I allow HVAC systems (and water heaters) to be supported on top of trusses in my area of jurisdiction (Clover, SC). For an official opinion of the acceptability of this practice, you should contact the Building Official in your jurisdiction.[/FONT]

Usually when bottom chords are 2x6 or greater then they typically designed for greater but limited loads…depending on the span… I have yet to call one out.
The most common issue I see are bottom chords nailed to interior partitions and lack of of bracing.

In the case of a H2O heater I am a little inquisitive…depending on capacity…a 50 gallon capacity can easily tip 500 pounds. Rarely do I see H2O heaters in the attic any more other than in custom / stick built roofs.

As Randy pointed out earlier, a water heater would be an issue if not over a wall and there was no supporting information to document that the trusses were designed for that load. Also, as an AHJ, I make them locate the water heater between the trusses, not concentrated on one truss.

Thanks. I like your answer giving your opinion, yet respectful of the other inspector.

Here’s my AHJ policy. (Keep in mind that I’ve been a BO less than 2 years).