Thread: cut truss for fan installation

I know that the truss manufacturers are not keen to the idea of their products being cut. While I doubt there will be a problem from this, I know it is against the truss makers recommendations.

What do you say when you see this, if anything?

One portion of the bottom cord was cut to install the whole house fan.

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John - If you don't report it as a problem, you are putting yourself out there as an engineer (and I'm assuming you're not). The issue isn't necessarily just "is it going to cause a problem". It's not right and could come back to bite you in other ways.

Call it for stupidity. It is up to someone else to decide what or if to do repairs. The strength is totally compromised.

Originally Posted by John Dirks Jr

I know that the truss manufacturers are not keen to the idea of their products being cut.

"not keen ... being cut"?

You mean that the truss manufacturers *FIND THAT TOTALLY UNACCEPTABLE*, right?

While I doubt there will be a problem from this,

Why do you "doubt there will be a problem" from that? If those trusses are loaded to their design during a severe storm or other load cause, that could definitely lead to a failure.

I know it is against the truss makers recommendations.

Yeah, like in *DO NOT DO IT*.

What do you say when you see this, if anything?

Just the same thing I always say "Engineered trusses ARE NOT TO BE CUT - have truss engineer or structural engineer design appropriate repairs.", and in this case add "Whoever cut that truss really screwed things up and that truss has been hacked in two. Remove the whole house fan and have the truss engineer design the engineered repair, and then inspect the repair work and issue a second engineering letter stating that the repairs have been made in accordance with the engineering design.", then add "Make at least two copies of that letter and laminate them, staple one copy to the trusses at the attic entrance and staple another copy to the trusses at the repair."

That is not one of those 'Well ... maybe" things - that is one of those 'DO IT EVERY TIME' things.

yea, ditto what Jerry said.

Thanks for reminding me how clear I need to be on issues like this. The report had already been sent when I posted this thread. After reading your responses, I felt the need to go back and see what I had said.

I think I covered it ok. I'm sure some of you might think my comment could have been better. If so, fire at will.

Here is the exact statement I made in the report regarding this cut truss.

"When the whole house fan was installed, one of the trussed was cut to make room. These engineered trusses are never intended to be cut. If they are they become weaker. In order to modify a truss, one would need approval from the truss designer. I did not see any notices posted in the attic that suggested that the modification had been approved. I do not know if this modification will cause a problem or not. So far it looks like it has not. To be sure the modification is ok, you will need to hire a structural engineer to check it out."

John,

I understand where you're coming from - I seldom see a resulting problem due to a cut truss. But agree or not, due diligence requires us to point it out. Even if the client did decide to live with it, the time will come when they will sell and another inspector comes along and points out the problem to someone else who may not be so forgiving. Clients generally seem to relate to that possibility.

John, I would offer a bit of advice approaching issues like this... simply be careful what you write:

"When the whole house fan was installed, one of the trussed was cut to make room. These engineered trusses are never intended to be cut. If they are they become weaker.

How do you know it is weaker? Common sense says it is, but are you an engineer?

In order to modify a truss, one would need approval from the truss designer. I did not see any notices posted in the attic that suggested that the modification had been approved.

Normally this would require a survey by a structural engineer, and permitting, etc.

I do not know if this modification will cause a problem or not. So far it looks like it has not.

Opening yourself up a bit here. Remember, just state the facts and do not speculate.

To be sure the modification is ok, you will need to hire a structural engineer to check it out."

When approaching something like this, it is better IMHO to keep your narrative brief and direct to the point without any opinions.

Just my two cents

Forget the cut truss I want to see the video of that attic insulation blowing around when that fan gets turned on.
Did I miss it, or did someone else mention the lack of cage around the fan?

Originally Posted by Jerry Peck

Remove the whole house fan and ...

Originally Posted by Markus Keller

Did I miss it, or did someone else mention the lack of cage around the fan?

Markus,

I think I covered the blowing insulation, the missing guard, etc., without identifying all the things which are wrong with that whole house fan ...

Originally Posted by John Dirks Jr

I know that the truss manufacturers are not keen to the idea of their products being cut. While I doubt there will be a problem from this, I know it is against the truss makers recommendations.

What do you say when you see this, if anything?

One portion of the bottom cord was cut to install the whole house fan.

A truss is an engineered product. When you cut it you void the manufacture's warranty and the engineer's seal on the calculations are void. Additionally whoever cuts a truss is responsible for all costs to fix it including investigation, engineering, materials, inspection, building permits, and contractor fees. It's not unusual for a cut truss to end up costing thousands of dollars to fix. That bottom chord might have 4000# of force in it under full load. A couple of toenails is not going to hold it.

Think of it this way. Is your car manufacturer going to cover your car's warranty if you cut the engine in half?

Originally Posted by Eric Barker

John,

I understand where you're coming from - I seldom see a resulting problem due to a cut truss. But agree or not, due diligence requires us to point it out. Even if the client did decide to live with it, the time will come when they will sell and another inspector comes along and points out the problem to someone else who may not be so forgiving. Clients generally seem to relate to that possibility.

True, most of the time the trusses will not fail with a single cut member. This is because #1 trusses are designed for more load than is typically applied most of the time. #2 Trusses typically fail at 2-3 times their design load. So the trusses on either side will handle an additional 50% in most cases without failing, nevertheless they probably do not meet code!! The main point of the building code however is to avoid the loss of life. So if someone wants to take the risk that severely overstressing the trusses will not cause catastrophic failure then go for it. I don't recommend it however unless you have an engineer's license or some really good insurance.

I love all the comments: good stuff!
You guys have it correct. The Truss manufacturer, the original people that did the engineering, by ICC code rule, must be the ones that give the appropriate repair design. It must have documentation so that the jurisdiction, city or county, can see it when they reinspect it because now a modification has been done. It may require a permit if this not new construction. I don't know if you are a home inspector or a building official but a certified inspector must approve the modification or the homeowners insurance may not cover any future problems. The guy that cut the truss in the first place should have to pay for the whole thing but it's up to the owner to pursue that. If he has to pay once believe me he'll never do it again.

Know thy code.

Originally Posted by Dee Stevens

I don't know if you are a home inspector or a building official but a certified inspector must approve the modification or the homeowners insurance may not cover any future problems.

Dee,

Actually, the engineer who drew the repair should be the one to issue a letter stating that the repair was repaired in accordance with the engineering design - that takes the 'blame card' off everyone and puts it on the engineer who designed it.

Yes, a code inspector could inspect it under a permit and sign it off, and that code inspector would be looking to see if the repair 'looked like it was done' in conformance with the engineering design, but so many of those do not have permits, and even if a permit is issued I'm not sure the code inspector is going to climb back into an attic way to the back to see it, so they will likely either (gulp!) see the engineering and sign it off, or (yeah!) see the engineering and say 'Okay, where is the engineering letter which states it was done this way? I need that before I sign the inspection off.'

Yep, the code inspector has that power, and should exercise it, then, when the code inspector signs it off, it is noted that 'engineering letter in file states repair is acceptable', meaning that the code inspector is signing it off based on the engineers okay, not on the code inspectors inspection of it - engineer still owns all of it.

You forgot to add "Staple one copy to the forehead of the idiot that cut the truss to put the fan in"


Just the same thing I always say "Engineered trusses ARE NOT TO BE CUT - have truss engineer or structural engineer design appropriate repairs.", and in this case add "Whoever cut that truss really screwed things up and that truss has been hacked in two. Remove the whole house fan and have the truss engineer design the engineered repair, and then inspect the repair work and issue a second engineering letter stating that the repairs have been made in accordance with the engineering design.", then add "Make at least two copies of that letter and laminate them, staple one copy to the trusses at the attic entrance and staple another copy to the trusses at the repair."

That is not one of those 'Well ... maybe" things - that is one of those 'DO IT EVERY TIME' things.[/quote]

Originally Posted by John Dirks Jr

I know that the truss manufacturers are not keen to the idea of their products being cut. While I doubt there will be a problem from this, I know it is against the truss makers recommendations.

What do you say when you see this, if anything?

One portion of the bottom cord was cut to install the whole house fan.

John,

It's not a matter of the truss manufacturers feelings. It's physics. When trusses are designed every piece plays an important part in handling the loads. The bottom chords do not behave like a traditional ceiling joist, no matter what they look like. Typically the bottom chord is in tension and when they are cut those forces can only push outward.

Only an engineer who specializes in truss repair design will have the knowledge and tools to know what effect this will have and how it will need to be addressed. Your report should say so in in very clear and direct language for your clients benefit and the protection of your own read end.

Yes Jack
You are correct. I did say that the engineer must prepair a fix and provide documents. I am also saying that is not the end of the road for this wayward wood butcher. There may be other painful consequences.

Dee

I find this all the time in homes from the 70's. I bet that home is also around that era? I note everyone just to be safe but the home is 30 plus years old and nothing has deflected. How many whole house fans do you see in homes 85 on up. They where great when A/C wasn't standard.

Originally Posted by Mike Schulz

I find this all the time in homes from the 70's. I bet that home is also around that era? I note everyone just to be safe but the home is 30 plus years old and nothing has deflected. How many whole house fans do you see in homes 85 on up. They where great when A/C wasn't standard.

The house was built in 1996.

With a whole house fan
Can't they afford A/C

Never seen one in a newer home

Originally Posted by Mike Schulz

With a whole house fan
Can't they afford A/C

Never seen one in a newer home

It depends on the climate. Some places have little need for air conditioning and a fan is more than adequate to cool the home.

Some homes here in Las Vegas have both evaporative coolers and AC units. The reason being the cost - the cost to run an AC in my home is over $350 a month in the summer. An evap cooler is basically a fan which uses very little electricity compared to an air conditioner.

Truss guy I can understand your point on that but he is from Maryland which isn't much different then here. About the only time it would be good to use is in the fall. Spring there is two much pollen and right after the pollen it's to muggy.