A sound occurring in the crawl space

[Henry MS]

I live in a 26-year-old ranch home over a crawl space.
Over the past year I have noticed a sound occurring in the crawl space when I use the washer (located in the garage at the far end of the house).

The sound reminds me of a metal that is exposed to extreme cold. To eliminate the cold temps within the crawl space, I had it completely insulated with a vapor barrier replaced, yet I am still experiencing a noise during the wash cycle. It does not last long - just a few seconds or so - but I am concerned this issue may cause damage to the water pipes which could cause substantial water damage to crawl space.

Do you have any ideas on where the problem lies and what I can do to resolve this matter?

[home improvement guy]

There are two solutions I have used in the past to eliminate noisy pipes. If the noise is caused by water hammer, which is common with quick closing valves such as on a washing machine, ice maker or dishwasher, then one solution is to install an expansion tank on the cold water line at the water heater or to install a shock absorber valve near the noisy appliance.

Sometimes hot water pipes will expand when the hot water reaches the colder sections of a water pipe. This expansion can create a popping or metallic sound as it expands. If this is the case, a more expensive yet more energy conserving repair would be to install a flow-sensing or timed hot water circulating pump near the water heater. A timed pump is set to operate during the times you normally use hot water. A flow-sensing pump senses when hot water is needed by the flow of the water and activates to send hot water to the faucet. No longer do you have to run the hot water faucet, wasting water, until the water turns warm. This conserves water saving energy and money.

You can choose an on-demand hot water system that uses a third pipe as a loop between the faucets and the water heater, or you can choose a system that uses a bypass valve between the hot and cold water pipes at the fixture. I have used a Grundfos pump and bypass valve that provide hot water on demand. Go to grundfos.com and search "circulating pumps."