pipes clanking and floor creaking with gas heating system

agtpendergast

First time here, and not literate about heating systems/piping. We have gas heating with forced air. The issue here is that whenever the heating system is on, there is a localized area between the first/second floor where there would be a intermittent knocking sound. I surmise this is due to expansion/retraction of piping and ??impingement on nearby structures. However, the floor directly above where the noise is localized to, creaks when I walk over it. The total area of floor creaking/pipes piping is around 4x4 ft

We bought the house 2 yrs ago and we also had new woodflooring done on the second floor so I'm not sure if the flooring job could have anything to do with it. We got the house in the spring so we didn't need the heat until winter, which was many months later, so the issue was not detected by us until that time. (Home inspection during escrow didn't turn up anything, probably because it takes a few minutes for the knocking noise to start plus it was warm during inspection).

I'm wondering-- is this something I need to address right away? Is this dangerous? Is the floor going to give away or something? Do I contact the heating guy or the flooring guy?

thanks

Jamie Hall

If this is really forced air, there aren't any pipes. If it were steam or hot water, then it is quite possible that there might be a pipe expanding and making a knocking sound while it was heating up. If it is expansion it would go away once the pipe was hot, though, and not continue through the whole cycle.

With forced air, it is possible for the same sort of thing to happen, but it might also be just noise from the air flowing through the ducting. If you can change the air flow through that duct, you can check that.

As to a structural problem? I wouldn't want to say for sure, but highly unlikely that there is a real structural problem. Creaking floors are almost always from a slightly loose connection between the floor and the joist or, in your case, between the old floor and the new floor. They can be very hard to find and fix...

agtpendergast

Yes, it is forced air I assume since it comes out the same vent as the AC does. Like you mentioned, the sound starts during initial heat up, stops in the middle, and the resumes after the heat shuts off.

The knocking sound is not very rapid; it's a knock--3 sec-- knock--3 sec, etc etc. The only concern is that the creaking floor is directly above the knocking sound.. So it seems too unlikely to be just coincidental.

Jamie Hall

Probably not coincidental -- but your description is classic expansion noise. You hear it when the system is warming up and when it is cooling off, but not in between. It is very likely that somewhere right in that area there is a bit of ductwork which is in contact with the floor. It might even be that a stray nail from when the new floor was installed hit and maybe even penetrated a duct (which is no big deal -- a tiny air leak isn't going to hurt anything). Fixing it, however, may be a very big deal indeed... although it is possible that if you can find where the floor creaks and fix that, you may fix the other at the same time. If you could get at it from underneath, it would make it much easier -- but I expect that that would be even harder to do!

JUGHNE

With the system switch on the thermostat in the off position, the house on both floors at about the same temp, turn the thermostat fan switch to "on". If you hear any noises then it is some loose ductwork part.....probably not to worry.
If the noise is only there with hot air and not coming from the furnace, then the expansion of ductwork.

If you had any structural problems with the second floor, the installers of your new floor would have found it and most likely let you know.

jumper

High aspect ducts can drum,especially when blower goes on.