Weight of Water

[Wet Dream]

If you have a gallon of water which weighs 8.345 pounds, does it increase weight when frozen to a solid? If so, how much weight does it gain in percentage? This is not a trick question, but I'm wondering how much more weight will be added to my porch roof when the rain-soaked snow freezes.

[sorry dog]

Water weighs less when frozen.
Ice floats for example
Actually the density of water changes slightly at different temps (in liquid form) but it's small.
However, in your example it will weight the same since the amount of mass doesn't change.

[clownpuncher]

Don't know the specifics of that answer, but, one cubic foot of water weighs in at 62.5 lbs. You need to determine the cubic feet you have accumulated on your porch and multiply that by 62.5. That will give you the weight on the porch. Also, one foot of water will exert about .434 PSI at its base.
Also, ice floats because it is less dense than liquid water. Ice is about 9% less dense. When ice forms, it takes up about 9% more space than it did as a liquid. So, a 1 cubic foot container of ice weighs less than a 1 cubic foot container of liquid water, and the lighter material floats to the top.

[mickeyfinn]

for calculating ice and snow loads insurance companies figure ice to weigh around 5 pounds per sqare foot for every inch thick. If you switch from ice to snow the number can go up very quick if it is packed snow since it gets even heavier.

[Wet Dream]

The MASS actually get bigger. Water expands as it freezes and exerts force. The oxygen expands and gets entrapped in the process which enables it to float. Mickeyfinn is right on the money, but thats the part I am questioning. Snow has been falling periodically for the last few weeks without a good melting and has been building up on the roof and porch roof since. Last night and most of today we have accumulated quite a bit of rain at 36*. When it freezes tonight and tomorrow, what is the added damage?

[Dr. Eagle]

Lets see...carry the one...
No Sorry Dog is absolutely right. The weight is actually less for the same given size or volume. But the water frozen can build up where the liquid stuff will run off.

[Checkmate]

Originally posted by clownpuncher
Don't know the specifics of that answer, but, one cubic foot of water weighs in at 62.5 lbs.
How is that possible? That would mean there is over 7 gallons of water in a cubic foot?
I would have guessed 4 or 5 gallons.:confused:

[clownpuncher]

Originally posted by Checkmate
How is that possible? That would mean there is over 7 gallons of water in a cubic foot?
I would have guessed 4 or 5 gallons.:confused:
7.48 gallons in a cubic foot. Trust me on this one ;)

[NorCal Gameshow]

dat's right...my cheat sheet says:
1 gallon of water =8.34 lbs.
1 cubic feet of water =7.48 gallons=62.4 lbs.