Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct this
by having them vent through the roof.

My question is this, wont the warm air coming out of those vents melt
the snow on the roof, and wont the resulting water end up freezing
into an ice dam as it tries to run down the cold roof where it runs
into more snow?

Yes and yes - Better to vent through the soffit or a gable end wall.

Then - Make sure your attic is insulated and well vented. Soffit vents
not blocked, gable or ridge vents as well.

I would love to someday use remote blowers for my kitchen and bath
ventilation needs. Something to consider as well.

J Kelly wrote:
Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct this
by having them vent through the roof.

My question is this, wont the warm air coming out of those vents melt
the snow on the roof, and wont the resulting water end up freezing
into an ice dam as it tries to run down the cold roof where it runs
into more snow?

Yes, that is a classic case of irresponsible workmanship.

--
Joseph Meehan

Dia duit

On Mon, 14 Nov 2005 18:41:47 GMT, "Joseph Meehan"
wrote:

J Kelly wrote:
Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct this
by having them vent through the roof.

My question is this, wont the warm air coming out of those vents melt
the snow on the roof, and wont the resulting water end up freezing
into an ice dam as it tries to run down the cold roof where it runs
into more snow?

Yes, that is a classic case of irresponsible workmanship.

I think you misunderstood what I meant, rereading what I wrote I see I
wasn't very clear. After I correct the incorrect venting by
installing roof caps and running both exhaust fans to said roof caps,
won't the heat coming out of them when the fans are on cause the same
snow melting and ice dams that I get now by just leaving the vents in
the attic? Or will it just melt a little snow around the vent and
then the heat is able to escape before causing more melting? I'm in
northern Iowa, we can get some big snows.

Warm air will go up, up, and away rapidly. Do make sure the attic is
properly insulated below, and vented, as others point out. That may
have contributed to your initial problem- one clue would be a fungus
colony in the rafters.

J

On 14 Nov 2005 13:11:52 -0800, wrote:

Warm air will go up, up, and away rapidly. Do make sure the attic is
properly insulated below, and vented, as others point out. That may
have contributed to your initial problem- one clue would be a fungus
colony in the rafters.

I do have another venting problem, some a-hole stuffed the soffits
with insulation, and only installed two vents on the roof when it
needs at least 4. Hope to find someone to fix that stuff as well. I
hate attics..

J Kelly wrote:
On Mon, 14 Nov 2005 18:41:47 GMT, "Joseph Meehan"
wrote:

J Kelly wrote:
Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct
this by having them vent through the roof.

My question is this, wont the warm air coming out of those vents
melt the snow on the roof, and wont the resulting water end up
freezing into an ice dam as it tries to run down the cold roof
where it runs into more snow?

Yes, that is a classic case of irresponsible workmanship.

I think you misunderstood what I meant, rereading what I wrote I see I
wasn't very clear. After I correct the incorrect venting by
installing roof caps and running both exhaust fans to said roof caps,
won't the heat coming out of them when the fans are on cause the same
snow melting and ice dams that I get now by just leaving the vents in
the attic? Or will it just melt a little snow around the vent and
then the heat is able to escape before causing more melting? I'm in
northern Iowa, we can get some big snows.

This is normally not a problem. You may want to put insulation around
the venting. I suggest solid metal, not flexible plastic.

--
Joseph Meehan

Dia duit

"J Kelly" wrote in message
...
On Mon, 14 Nov 2005 18:41:47 GMT, "Joseph Meehan"
wrote:

J Kelly wrote:
Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct this
by having them vent through the roof.

My question is this, wont the warm air coming out of those vents melt
the snow on the roof, and wont the resulting water end up freezing
into an ice dam as it tries to run down the cold roof where it runs
into more snow?

Yes, that is a classic case of irresponsible workmanship.

I think you misunderstood what I meant, rereading what I wrote I see I
wasn't very clear. After I correct the incorrect venting by
installing roof caps and running both exhaust fans to said roof caps,
won't the heat coming out of them when the fans are on cause the same
snow melting and ice dams that I get now by just leaving the vents in
the attic? Or will it just melt a little snow around the vent and
then the heat is able to escape before causing more melting? I'm in
northern Iowa, we can get some big snows.

Here's an interesting site concerning ice dams, lots of examples.

http://doityourself.com/waterproof/icedam.htm

If you are concerned that the warm air from the vents will melt the snow,
investigate insulated vents and/or higher stacks.

On Mon, 14 Nov 2005 21:41:39 GMT, "Joseph Meehan"
wrote:

J Kelly wrote:
On Mon, 14 Nov 2005 18:41:47 GMT, "Joseph Meehan"
wrote:

J Kelly wrote:
Last winter after a heavy snow I had a couple of problems with ice
dams. One above the exhaust hood over the stove, another above the
bathroom. Both appear to be caused by improper installation of the
fans, they both vent into the attic space. I'm going to correct
this by having them vent through the roof.

My question is this, wont the warm air coming out of those vents
melt the snow on the roof, and wont the resulting water end up
freezing into an ice dam as it tries to run down the cold roof
where it runs into more snow?

Yes, that is a classic case of irresponsible workmanship.

I think you misunderstood what I meant, rereading what I wrote I see I
wasn't very clear. After I correct the incorrect venting by
installing roof caps and running both exhaust fans to said roof caps,
won't the heat coming out of them when the fans are on cause the same
snow melting and ice dams that I get now by just leaving the vents in
the attic? Or will it just melt a little snow around the vent and
then the heat is able to escape before causing more melting? I'm in
northern Iowa, we can get some big snows.

This is normally not a problem. You may want to put insulation around
the venting. I suggest solid metal, not flexible plastic.

Thanks for the replies. I have my plumber lined up to fix the vents
later this week. I don't want to cut the hole in my roof myself, and
I hate attics!