TOPIC: Shake, Rattle and Blow

One thing to check for in new construction is proper installations.  For a home inspector that can be daunting.  The building supervisor has been on site for 100 or 120 days.  The inspector only gets a couple of hours.

You would think everything would be installed properly!  After all, there are various subcontractors coming in, each a specialist in their field, and they are putting things together piece by piece.

Certainly one of my jobs is to test equipment.  I always cross my fingers that no serious damage will result - dishwashers not connected, sparking electrical, overflowing toilets or washing machines (each of which has happened to me on new home inspections).

On this particular inspection, when the basement furnace was turned on, there was a serious vibration sound through the returns.  My client's eyes bulged a bit, "What is that!?"  I knew immediately.

"Walk this way."  Then I do the Mel Brooks thing with a cute, albeit obnoxious, sashé toward the basement stairs.  Sure, tell me you don't do this...

Furnace connections are made up of two basic sections.  The gas burner, AC and air handler are on the bottom, and immediately above is the main supply duct which services the house with hot and cold air.

Those two sections are separated by what is called a vibration damper.  It is made up of two pieces which attach to the ducts and are separated by a rubber membrane.

Properly installed, no vibration or sound from the mechanisms below transfer through the house via the other duct work.

A bit hard to see in this photo, that membrane has been crushed and the two sections are touching.  More too, the membrane was split during installation and air was pouring out!

THIS IS MY SECOND SUCH TOUCHING VIBRATION DAMPER ON NEW CONSTRUCTION THIS WEEK!

The vibration sound we heard will only get worse with time.  Why?  Because gravity works.

I'll bet that when my clients pointed this out to the supervisor his response was that it was already on his list...

My recommendation:  Even though it's new construction, don't assume anything!  You know what happens when you assume...  Oh, and hire a home inspector!

Yikes. What the cost to fix that?

No know.

It's funny Jay, I talk to people all the time about the new home they just built, and didn't have inspected. They figure it's new, what's to inspect? This is yet another example of why a home inspection is needed on a new home build. Thanks for spreading the word.

Hi fellow's.
to be able to discuss some mechanical system issues, first , proper terms have to be used..term exhaust in the article above, is not the proper one..exhaust and supply are not the same..and to say, with big words, that just touching of a damper is the reason for some "serious vibration noise" in furnace installation is just jumping to conclusion too soon..also, you said "there was a serious vibration sound through the returns". but from your picture, one can not tell if this is supply or return duct..what if your furnace is not properly level..or if it is oversized..are the ducts properly sized..  so, suggestion is - be careful with "the big words".. 

Hi Joe!  Welcome to the board.  I am honored that you spent your first comment on my post!

I was there an hour before my clients and had seen the furnace vibrate and knew what to say to them.  It was no rash judgment.  And they could hear the vibration in the return duct in the hall.

Back when I first got into the business, 1981, furnaces were said to "exhaust."  Whether it was the proper word or not, that was the word used.  But in your honor, I have changed that word to "supply" and will try to be more obsequious and less pedantic with the "big words."

I don't remember seeing a vibration damper on the return side near the furnace.  Could be I have, but in this case, as it says in the post, that picture is of the "supply" duct...

Thanks for stopping by.  Hang around.