Question about snow on roofs

[Riddler]

what crack-smoker came up w/ this?
copper water piping can handle several HUNDRED psi....
it IS the expansion of frozen water that splits piping...
been there/done that 24+ years (professionally)

Several thousand, actually.

The weakest point is the soldered fitting, particularly in old pipes with lead solder.  That's likely where the story comes from.Of course, if someone has bad (acidic) water that has weakened the piping, then all bets are off.  I've seen copper pipes so flimsy that you could poke your finger through them.  Water pressure could definitely burst weakened pipe.

Joe

hmmmm. why then, does frozen piping split along its length?
yes, occasionally, soldered fittings pop off, but type M copper (thin wall), and even type L will split along the length. Bad solder joints are a weak point. Some guys don't know how to solder properly. pipe/fittings not cleaned enough; not enough , or wrong kind of flux........not enuf solder

[alohamonkey]

invest in metal roofs.

very good idea . . . but i promised myself i'm not putting any more money into this house.  maybe on the next one

[alohamonkey]

Elec. roof cable is the way to go here.

where do i find out more about this?

[MaineShark]

hmmmm. why then, does frozen piping split along its length?

From the ice.

The water pressure would be enough to pop fittings, which is likely where the water pressure story comes from.

Excepting weakened pipes, in which case the water pressure would probably be enough.

Technically, water is what splits the pipe, even when it's bursting out the side (that's why it gets that rounded "bulge" shape).  But that's water which has been trapped by the ice (eg, between two frozen spots), so opening the faucet wouldn't help.

yes, occasionally, soldered fittings pop off, but type M copper (thin wall), and even type L will split along the length. Bad solder joints are a weak point. Some guys don't know how to solder properly. pipe/fittings not cleaned enough; not enough , or wrong kind of flux........not enuf solder

Exactly.  Even good solder joints aren't as strong as pipe.  Weak solder joints are dramatically less strong, and easily pop off at much less pressure that it would take to leak through a faucet cartridge.  That's likely where the theory of relieving pressure by leaving the faucet open comes from.  It certainly wouldn't protect the pipe itself, unless the pipe was ridiculously weak... the faucet cartridge would leak through long before the burst pressure of the pipe was reached.

Joe

[Russell Kanning]

invest in metal roofs.

might not solve the problem of thawing and freezing

better insulation between the heat and the roof fixes it even with shingles

[Lloyd Danforth]

Builders use both rubberized membrane and an airflow along the underside of the roof sheathing between eve vents and ridge venting or gable vents at the uninsulated space at the top of the house to avoid ice damming from forming or, at least being sucked into the heated part of the house.

[Riddler]

Elec. roof cable is the way to go here.

where do i find out more about this?

Most hardware stores sell it & the instuctions are easy to understand. It takes some measuring &calculating (on the box as well) to get the proper length cable. sold as a kit w/ attachment clips & then you simply plug it in.

[Michael Fisher]

Yes, if you live in a house with plumbing through outside walls, or with poor insulation, you should leave your faucets open a crack to drip.

My understanding is that you should never do this with a manufactured home, and I'm not sure it is even true with a constructed home.

With a manufactured home, allowing the faucets to drip enables ice buildup in pipes under the home. If you're afraid of freezing pipes, then use heat tape during the winter and change it regularly. If your home is not heated, then turn off the water supply and open all the faucets. This is what a professional home inspector once told me.

With a constructed home, either heat the entire home or turn off the water supply and open all the faucets.

I'm no expert on this, so I would like verifiable, credible sources to refer to regarding these ideas before anyone acts on them.

[Riddler]

Yes, if you live in a house with plumbing through outside walls, or with poor insulation, you should leave your faucets open a crack to drip.

My understanding is that you should never do this with a manufactured home, and I'm not sure it is even true with a constructed home.

With a manufactured home, allowing the faucets to drip enables ice buildup in pipes under the home. If you're afraid of freezing pipes, then use heat tape during the winter and change it regularly. If your home is not heated, then turn off the water supply and open all the faucets. This is what a professional home inspector once told me.

With a constructed home, either heat the entire home or turn off the water supply and open all the faucets.

I'm no expert on this, so I would like verifiable, credible sources to refer to regarding these ideas before anyone acts on them.

Gravity draining of water piping is a risky business.
There exist, many times, trapped areas w/in the plumbing system, which is why we ALWAYS use compressed air to evacuate the water distribution piping, to prevent split-pipe syndrome.
Faucet dripping in manuf. housing does not cause ice buildup in piping beneath the unit. urban myth.
an extended horiz. drain COULD ice up, but this is a rarity

[Beth221]

is this why some folks have those red or green metal roofs, so the snow slides off it? 

[Riddler]

is this why some folks have those red or green metal roofs, so the snow slides off it? 

No dear,
that's just at Christmas

[Beth221]

i dont believe you. 

[Riddler]

i dont believe you. 

would i lie to you, cindy lou-who?
(picture the grinchy-grinch)

[Beth221]

someone who is challenging me AND busting my balls!


arnt you brave!

hehee.

[Michael Fisher]

Gravity draining of water piping is a risky business.
There exist, many times, trapped areas w/in the plumbing system, which is why we ALWAYS use compressed air to evacuate the water distribution piping, to prevent split-pipe syndrome.
Faucet dripping in manuf. housing does not cause ice buildup in piping beneath the unit. urban myth.
an extended horiz. drain COULD ice up, but this is a rarity

This is why I want a credible source. The words "urban myth," especially spoken by someone on an Internet forum, do not constitute a credible source.