Thread: Can you see the top chord of a truss with thermal image camera while standing on roof

I am a solar contractor in sunny Florida. In this hurricane prone state it is imperative that we get the mounting feet, for the rails that support the solar panels, in the center of the top chord of the truss. We spend a lot of time trying to find that center point using various methods and I'm looking for a better way!

Someone suggested to me that a thermal imaging camera might be able to see the truss or framing member while standing on the roof. As I imagine that many of you inspectors have such a camera, could you please tell me if this would work on an asphalt shingle, metal or tile roof? If so, would the resolution be sufficient that you could easily identify the center of a truss with a high degree of certainty/accuracy?

As a solar contractor, I also try to help homeowners reduce their electrical consumption through various energy saving suggestions. A thermal imaging camera could slso allow me to look for areas of poor insulation and other things that would effect ones electrical usage. Is there a consensus among you guys about the best value in thermal imaging cameras? Do most of you tend to gravitate to a specific brand or model?

If a thermal imaging camera is not an option, is there any other creative ways to "see" the truss from a roof top that you guys can think of?


Thanks for your thoughts.

David

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I second Fritz's idea of using your feet. It's usually pretty obvious where the framing is.
Sorry-- I don't have an IR camera to fully answer the question.

I doubt it because of the loss of contact and thermal bridging from the truss to the sheathing to the underlayment to the shingles.

I could see the webs in concrete block with an infrared camera, but there was continuous contact all the way through to the surface.

With shingles only being nailed ad 6 "points" and having been laid on "wrinkled" underlayment, which was on nailed a "points" to the roof sheathing - I think there will be to little thermal transfer to use that reliably.

I never tried it on a shingle roof. I could see the mortar and foam patties under concrete tile, but not the trusses below.

Another question is "How are you flashing those mounting points so that you are not violating the water shedding ability and shingling effect of water drainage, and not violating the roofing system installation requirements for warranty coverage, both the manufacturer's and the roofer's?"

Originally Posted by DavidA Jensen

Someone suggested to me that a thermal imaging camera might be able to see the truss or framing member while standing on the roof.

It may work on one roof and then not work on another.

A thermal imaging camera could slso allow me to look for areas of poor insulation and other things that would effect ones electrical usage.

Missing Insulation is one thing that an IR Camera can do very well.
See the image attached.

David

Best

Ron

Originally Posted by Jerry Peck

Another question is "How are you flashing those mounting points so that you are not violating the water shedding ability and shingling effect of water drainage, and not violating the roofing system installation requirements for warranty coverage, both the manufacturer's and the roofer's?"

Most companies just lag the feet right into the shingles and use sealant to [hopefully] keep out the water. We don't consider that adequate since PV systems should be generating electricity on the roof for 30 - 40 years +. We use 90/1000 aluminum flashing that goes under the shingle tab and then we mount our foot on that, with a long-lasting sealant between the flashing and the mounting foot. I have a very high degree of confidence in our system. I can't say that for most of the guys our there.

Thanks to those who replied. I was hoping that thermal imaging would work, but it's not sounding promising. It's true that you can get pretty close by using your feet but we try hard to get right at the center of the truss and my feet don't usually allow me to be that accurate. We've tried several stud finders with no success (and I didn't expect it to work). With all the nails holding down the tar paper and the shingles, I haven't found a magnet to work either. I just would really like something that would give me x-ray vision!

Thanks again.

Originally Posted by DavidA Jensen

It's true that you can get pretty close by using your feet but we try hard to get right at the center of the truss and my feet don't usually allow me to be that accurate.

What I've always done when finding studs, trusses, etc., is to locate as best I can with my feet or hand, then take what I think is the center, drive a nail part way in straight to make sure I hit solid into it, then pull the nail out and drive it part way in at an angle to the left and then to the right, if you still hit wood, you are real close to center. If you hit wood one way and air the other way, you are close to that air side and not center.

Someone suggested to me that a thermal imaging camera might be able to see the truss or framing member while standing on the roof.

DJ: There are inspectors and then there are "thermographers". The latter pretend to be inspectors with ray guns. Their ray guns can do anything, where they themselves can do little or nothing. It was likely a "thermographer" that led you astray.

As I imagine that many of you inspectors have such a camera

DJ: Actually, the vast majority of inspectors are not "thermographers". This is a good thing for the housing stock of this country and protects prospective homebuyers from being sold ocean tanker quantities of oil of viper. But, and I hate to admit this, as the talent pool in this profession is dwindling, the number of "thermographers" is increasing. The manufacturers of the nearly useless toys have made their fortunes and are now selling the whizbangs for less than the cost of a new car.

Give it 5 years and they will be given away free in boxes of breakfast cereal, where they belonged all this time.

Originally Posted by A.D. Miller

DJ: There are inspectors and then there are "thermographers". The latter pretend to be inspectors with ray guns. Their ray guns can do anything, where they themselves can do little or nothing. It was likely a "thermographer" that led you astray.



DJ: Actually, the vast majority of inspectors are not "thermographers". This is a good thing for the housing stock of this country and protects prospective homebuyers from being sold ocean tanker quantities of oil of viper. But, and I hate to admit this, as the talent pool in this profession is dwindling, the number of "thermographers" is increasing. The manufacturers of the nearly useless toys have made their fortunes and are now selling the whizbangs for less than the cost of a new car.

Give it 5 years and they will be given away free in boxes of breakfast cereal, where they belonged all this time.

Good one Aaron... This one of your better post

Best

Ron

YES you can see the rafters with an IR Camera.

Best

Ron

Time of day should not be a factor. if its hot out hit the ac. if its cold out hit the heater.

These images are from a FLIR BX320 $ 13K

I have a FLIR B2 FOR SALE that will do the same thing $ 4,200 it comes with a 45 Degree lens a must item for one of these cameras. its almost just like a BX320...

you are looking for a camera call me.

707-570-2000

Best

Ron

RB:

Anybody that would drop $13K on a ray gun is either completely diluded or a trust fund baby.

By the way, I have some other things you might be interested in:

1. An Ovaltine Secret Decoder Ring. Paid little. For you only $795.

2. A Cracker Jack Plastic Carpenter Square. Paid little. Just $1350.

3. A Cracker Jack Goat Standup Figure. Paid little. A mere $2055.

Or, you can just trade me for the B-2. You will be getting the better deal.

Aaron you walk by this kind of stuff every day... Just like a blind man...

And you say to the nice people that employed you... YUP I inspected. And i did not find any thing... Then they employ some one like me with a $ 13K ray gun and I find this kind of stuff... Then the nice people say things like Thanks Ron that RAY GUN did the job.

Aaron the Music is to loud Turn it down...

Best

Ron

Just like a blind man...

Scooter Boy:

The last time this blind man looked at any of the inspector SOPs that could possibly apply to me I noted the term "visual inspection". I also noted the lack of a requirement for me to use "special tools".

And, though it may pain you to admit it - therefore you will not admit it - you cannot possibly charge enough more per inspection to pay for your secret decoder ring in this lifetime. Not in my market. Probably not in yours either.

And, I do not accrue the tremendous liability that you do for not shooting every square inch of the building with your ray gun.

Grow up. Put on long pants. Act like a man.

Aaron I pick up $ 200 = $ 400 A day with my RAY GUN...

Your like a cup with holes in it.

Best

Ron

I paid $13,000 for my ray gun when I bought it in 2004, and which I sold for $3,500 in 2007 as I no longer needed it. Sure wish I had kept it.

Now, $13,000 buys a WHOLE LOT MORE "ray gun".

Your like a cup with holes in it.

RB: Yep, the same kind of cup that leaks effluvia all over your shoes when you fill it to the rim with BS.

So then, the math tells me that, if your statement is true - and surely it must be, because you made it, you want us to believe that you make $73K-$109K each year with your "wittle way gun" in addition to your normal fees? Excuse me while I laugh hysterically, just for a hour or so.

Coming, as you do, from the Land of Hype which has brought us all things good from the Gold Rush to reality TV, I would expect for you to hang out a lie like that to dry. I hope it does soon, because the stench is overwhelming.

Originally Posted by A.D. Miller

RB:

you want us to believe that you make $73K-$109K each year with your "wittle way gun" .

Aaron there must be some thing wrong with you I don't think I have ever ran into some one with so much ( HATE ) in there heart... Dude I make what i make and people pay for that service because the want me to find the stuff that if find.... what is $ 200 extra on and inspection when you are paying $ 500K or 2ML For a home out in this area. My market supports this... The type of work you is not the same as the type of work i do... I provide a Termite inspection a HI Inspection and a Thermal imaging all at the same time...These type of inspection start at$ 750.00 and go up from there...

Go look in that mirror some more. Lighten up a bit life is to short...

Best

Ron

The type of work you is not the same as the type of work i do...

RB: We will certainly agree on that.

Originally Posted by Ron Bibler

YES you can see the rafters with an IR Camera.

Best

Ron

Great! Someone with an actual picture to prove it can be done! Thanks so much for the evidence! Now for the reality in a situation like mine. If you were standing on the roof and pointing the camera down by your feet, would you be able to see the truss with enough resolution to mark the truss within, say, 1/4" of center? Lets get even more specific. Say that you were kneeling on the roof with the camera pointing down in the approximate location of a truss. Could you see the truss in the display and than place your finger on the roof deck so that it was visible in the picture so that you could actually put your finger on the center of the truss? You would then be able to mark the truss with a crayon and move on to the next one? For this to be an option for us, as solar installers, this is pretty much how I think it would have to work.

If this does not work, I am also considering a Bosch D-tect 100 as seen here: Bosch - The Wallscanner D-tect 100 - The universal detection device or Bosch D-Tect 100 Wallscanner. They cost upwards of $1,000 US and I've read of a couple solar guys who have had pretty good luck with them on asphalt shingle roofs. Milwaukee is coming out with a similar looking product in the next month or two (Milwaukee M12 Sub-Scanner 2290-21 - Ohio Power Tool) so it is too early for any feedback on this new device although it looks to be much less expensive. More important than price, is something that will work reliably.

A bigger challenge is trying to find trusses on a metal roof. I don't think that thermal imaging or one of the tools I listed will work there. Often times you can get in the attic and measure over from the attaching screws to a truss and then transfer that measurement to the roof deck. However, this is nearly impossible down near the eaves unless you remove soffet material.

Thanks again for your thoughts.

Originally Posted by Jerry Peck

What I've always done when finding studs, trusses, etc., is to locate as best I can with my feet or hand, then take what I think is the center, drive a nail part way in straight to make sure I hit solid into it, then pull the nail out and drive it part way in at an angle to the left and then to the right, if you still hit wood, you are real close to center. If you hit wood one way and air the other way, you are close to that air side and not center.

The nail on center and on an angle is how we determine the very center, just like you say here. We get close by either measuring from a "known" point or tapping or using our feet. I'm just always looking for a better way that doesn't involve penetrations. Of course, if we are making our test hole where a mounting foot is going, the hole itself is not a big deal. It is, however, if you are trying to locate the truss at a point where you will not be mounting a foot.

[quote=DavidA Jensen;89185]Great! would you be able to see the truss with enough resolution to mark the truss within, say, 1/4" of center? YES

Could you see the truss in the display and than place your finger on the roof deck so that it was visible in the picture so that you could actually put your finger on the center of the truss? YES

Keep in mind that the better your camera to the better the Image...

Each application of thermal imaging like anything may pose its own problems. One just needs to look out side of the box...

Best

Ron

Originally Posted by DavidA Jensen

Keep in mind that the better your camera to the better the Image...

Companies like FLIR have so many models out there that its hard to know what to get and what I need. What aspect of the camera needs to be "better" to increase the likelihood of success? In other words, what do I need to look for in a camera. Feel free to be specific as to brand/model if you like or mention the specs that I would need to do what we've talked about. Cost is certainly a factor but nothing is more expensive than a tool that doesn't do what you need it to.

Thanks.

Originally Posted by DavidA Jensen

Companies like FLIR have so many models out there that its hard to know what to get and what I need. What aspect of the camera needs to be "better" to increase the likelihood of success? In other words, what do I need to look for in a camera. Feel free to be specific as to brand/model if you like or mention the specs that I would need to do what we've talked about. Cost is certainly a factor but nothing is more expensive than a tool that doesn't do what you need it to.

Thanks.

If you want to Email me I can help with more of that information.

Best

Ron
ronofexcellence@earthlink.net

The answere is yes but not always. It depends on material.temperature delta T,atmospheric conditions, dewpoint and the experience of a Certified THERMOGRAPHER and the quality of the camera.
There are folks out there that lay claim to the title"Thermographer" who just own a camera. No experience and no actual training.Sort of like builders who claim to be Home inspectors.
Do I need to say that I take exception to comments made by someone who has no practical and from the sound of it ,no real knowledge of Thermography?
Like anything else that is relatively new to the industry it will usually diagree with the old dog who won't learn a new way of doing things, The science of thermography has been proven over and over again.
Don't feel the need to reply old dog.

probably a rhetorical question since it implies a simplistic answer. I am suggesting that if you use the camera be able to back up to your client why the IR photo is able to show the image,(it is not a Kodak) as it will go along way in supporting your conclusions to the client and if need be in a deposition or court hearing. If you can't explain why you see what you see ,be prepared to get the short end of the stick if there is ever litigation. Like any certification,it can only help you if you take the time to learn as much as you can I have met a number of people who have used the camera improperly and had to go back and change their conclusions once they have gone through the proper training and realize they never used the correct settings when they did the inspection. If you have a camera, why not learn all the ways to use it,the right way?

Originally Posted by Gary wellborn

probably a rhetorical question since it implies a simplistic answer. I am suggesting that if you use the camera be able to back up to your client why the IR photo is able to show the image,(it is not a Kodak) as it will go along way in supporting your conclusions to the client and if need be in a deposition or court hearing. If you can't explain why you see what you see ,be prepared to get the short end of the stick if there is ever litigation. Like any certification,it can only help you if you take the time to learn as much as you can I have met a number of people who have used the camera improperly and had to go back and change their conclusions once they have gone through the proper training and realize they never used the correct settings when they did the inspection. If you have a camera, why not learn all the ways to use it,the right way?

Gary,

Let me get this straight: For the original poster, HE will not be able to see the top chord without becoming a trained Thermographer and will not be able to back up his statement of "Yep, Tony, move to the right, to the right, to the right - THAT'S IT right there." in locating that truss top chord?

SOME PEOPLE try to make infrared cameras and being able to use them out to be only the domain of the ultra smart or ultra trained.

SOME PEOPLE try to push infrared cameras off as being the cure-all and see-all, while other pooh-paw infrared camera as being useless and overkill (not sure how something can be "overkill" if it is "useless", but ... ) ...

Any way, I digress and have now fairly bashed both extremes on the head equally.

I can see that thermography has a special place in the dump for a number of people out there and I will not even attempt to change their mind. I just believe that people out there are doing those of us who have taken the time to actually learn the science and effective way TO USE iNFRARED AS SOMETHING OTHER THAN A HAMMER.will pay the price for those who are too lazy and too briliant. I am proud to call my self a thermographer and in the fact that I know the right way to use the camera. I also have learned how to help my client know what they are looking at and can correctly explain the science behind IR if they decide they want to know. The fact that there are those out there that just take a picture with out knowing if they even have the proper emissivity set on the camera hurts their credibility and any one they work for.
You may have been ahead of your time when you first started using your camera but I think you are likely to realize all over again the benefits both to you financially and to your clients by catching something someone else would have missed.
One last thing, there are very good cameras out there now that are below the ten thousand price range,even below the six thousand dollar mark. Won't matter how much you pay if you don't know the right way to use it.

Originally Posted by Gary wellborn

You may have been ahead of your time when you first started using your camera but I think you are likely to realize all over again the benefits both to you financially and to your clients by catching something someone else would have missed.

I suspect you are not aware of as much as you think you are.

I not only had my camera back then, I was also a Level I Thermographer, AND *I DO* understand and recognize the benefits of infrared, AND their limitations.

SOME PEOPLE do not understand their limitations and promote the infrared cameras as the cure-all and catch-all ... AND THEY ARE NOT.

HELPFUL? Absolutely!

But are they the end-all TOOL for home inspectors? Absolutely NOT!

And until pseudo-Thermographer realize that, they will not be using infrared as they should be used.

If you are a true Thermographer, you realize what the infrared camera CAN do ... AND ... what the infrared camera CANNOT do.

SOME here think the infrared camera can do it all, and they are incorrect.

The VERY BEST TOOL a home inspector has is ... that soft tissue between their ears ... and if they use that AND EVERY TOOL they have available, then they will be able to do a better inspection than those who refuse to use every tool available, and even better than those who think any given tool is the be-all and end-all.

Jerry,I think we can agree that nothing is the end all or the perfect tool for every occasion. I don't think that is what I implied but I will agree with more of what you said when you stated the obvious that the grey matter and someones experience is ultimately the best tool at anyones disposal. I am going to suggest that more people need to take the leap into thermography in order to have ONE of the best tools a home inspector can have in his bag of tools. I also suggest that when they do add it,take the time to get the proper training so they don't make mistakes that can cost them in the end. If you don't want to add this tool then don't knock it and don't make thermographers out to be something most certified thermographers are not,scammers or incompetents.
I think I will use this as my tag line;"Continue to learn or get left behind"

Gary

You know those politicians you can't stand, or people in general, that spend all there efforts trying to make themselves look good by bashing the crap out of everybody else. Well holy smokes!!!!! Take a look at Arron the wonderful's website. Say no more.