Hot Porch Roof
 

I have a large front porch with a roof about 8 feet up. It is open on
the bottom so you see the sheathing and joists (2x6's). When the sun is
on it the heat really radiates down to the porch area making it hot as
hell even though you are in the shade.

I am considering putting up a "ceiling" but good circulation won't be
easy without a fan. The porch roof extends about 10 feet over the
original roof and shingles of the house so I suppose I could close it up
and add a fan. If I do it I'm thinking of using 3.5" insulation so
there is plenty of room for air circulation between the insulation and
the sheathing.

Any other ideas before I get broiled?

Tony

Hot Porch Roof
 

Tony wrote:
I have a large front porch with a roof about 8 feet up. It is open on
the bottom so you see the sheathing and joists (2x6's). When the sun
is on it the heat really radiates down to the porch area making it
hot as hell even though you are in the shade.

I am considering putting up a "ceiling" but good circulation won't be
easy without a fan. The porch roof extends about 10 feet over the
original roof and shingles of the house so I suppose I could close it
up and add a fan. If I do it I'm thinking of using 3.5" insulation so
there is plenty of room for air circulation between the insulation and
the sheathing.

Any other ideas before I get broiled?

Tony

Forget the insulation.

Radiant barrier. Cheap, 95% effective, easy to install.

Hot Porch Roof
 

On Jul 25, 3:47*pm, Tony wrote:
I have a large front porch with a roof about 8 feet up. *It is open on
the bottom so you see the sheathing and joists (2x6's). *When the sun is
on it the heat really radiates down to the porch area making it hot as
hell even though you are in the shade.

I am considering putting up a "ceiling" but good circulation won't be
easy without a fan. *The porch roof extends about 10 feet over the
original roof and shingles of the house so I suppose I could close it up
and add a fan. *If I do it I'm thinking of using 3.5" insulation so
there is plenty of room for air circulation between the insulation and
the sheathing.

Any other ideas before I get broiled?

Tony

Obama says white paint everything

Hot Porch Roof
 

HeyBub wrote:
Tony wrote:
I have a large front porch with a roof about 8 feet up. It is open on
the bottom so you see the sheathing and joists (2x6's). When the sun
is on it the heat really radiates down to the porch area making it
hot as hell even though you are in the shade.

I am considering putting up a "ceiling" but good circulation won't be
easy without a fan. The porch roof extends about 10 feet over the
original roof and shingles of the house so I suppose I could close it
up and add a fan. If I do it I'm thinking of using 3.5" insulation so
there is plenty of room for air circulation between the insulation and
the sheathing.

Any other ideas before I get broiled?

Tony

Forget the insulation.

Radiant barrier. Cheap, 95% effective, easy to install.

What kind of radiant barrier? I don't want it to look like aluminum
foil. Maybe I could use the radiant barrier instead of insulation then
the sheathing under that for looks.

Tony

Hot Porch Roof
 

Staple up a mylar foil space blanket? To the bottoms of the
rafters?

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"HeyBub" wrote in message
m...

Forget the insulation.

Radiant barrier. Cheap, 95% effective, easy to install.

Hot Porch Roof
 

Look good. Cook in the summer. What a choice.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Tony" wrote in message
...

What kind of radiant barrier? I don't want it to look like
aluminum
foil. Maybe I could use the radiant barrier instead of
insulation then
the sheathing under that for looks.

Tony

Hot Porch Roof
 

"Tony" wrote in message
...
HeyBub wrote:
Tony wrote:
I have a large front porch with a roof about 8 feet up. It is open on
the bottom so you see the sheathing and joists (2x6's). When the sun
is on it the heat really radiates down to the porch area making it
hot as hell even though you are in the shade.

I am considering putting up a "ceiling" but good circulation won't be
easy without a fan. The porch roof extends about 10 feet over the
original roof and shingles of the house so I suppose I could close it
up and add a fan. If I do it I'm thinking of using 3.5" insulation so
there is plenty of room for air circulation between the insulation and
the sheathing.

Any other ideas before I get broiled?

Tony

Forget the insulation.

Radiant barrier. Cheap, 95% effective, easy to install.

What kind of radiant barrier? I don't want it to look like aluminum foil.
Maybe I could use the radiant barrier instead of insulation then the
sheathing under that for looks.

1" Styrofoam, backed with aluminum foil, foil side up, against the
sheathing. Cut it into strips, making a snug fit pressing them between the
rafters. Available in 4 x 8 sheets. The white Styrofoam will look good too.

Hot Porch Roof
 

Tony wrote:

Any other ideas before I get broiled?

Tony

Forget the insulation.

Radiant barrier. Cheap, 95% effective, easy to install.

What kind of radiant barrier? I don't want it to look like aluminum
foil. Maybe I could use the radiant barrier instead of insulation
then the sheathing under that for looks.


You could do that. You could cover the radiant barrier with almost
anything - even paint.

You should probably also plan on some way for the hot air to escape...

Hot Porch Roof
 

Hot Porch Roof
 

On Jul 26, 11:53 am, Tony wrote:
A fan doesn't stop *radiant* heat.

Not directly, but by conducting heat away from the sheathing, wouldn't
a properly placed fan lower the temperature of the sheathing thus
reducing the amount of heat it radiates?

Hot Porch Roof
 

Tony wrote:

... and paint the roof white

I have been tempted! That part of the roof can not be seen from
ground level anyway.

If you can't see it, that's a good trick. It's often done on commercial
buildings with flat roofs.

The reason you don't want to do it if the roof's visible is that turns an
icky color and stains from the junk in the air.

Hot Porch Roof
 

Larry The Snake Guy wrote:
On Jul 26, 11:53 am, Tony wrote:
A fan doesn't stop *radiant* heat.

Not directly, but by conducting heat away from the sheathing, wouldn't
a properly placed fan lower the temperature of the sheathing thus
reducing the amount of heat it radiates?

I've considered ceiling fans but I don't know where I could properly
place them to do the job. I think ceiling fans would just blow hot air
all around me. If I'm lowering the temperature of the sheathing then
I'm transferring the heat from the sheathing and into the air. I just
don't see any easy way to use fans without a lot of turbulence, so I'd
be blowing hot air all around. I'm tired, does that make any sense?
BTW, the roof is 28' x 12' and a little more than a 1:12 pitch.

Hot Porch Roof
 

HeyBub wrote:
Tony wrote:
... and paint the roof white
I have been tempted! That part of the roof can not be seen from
ground level anyway.

If you can't see it, that's a good trick. It's often done on commercial
buildings with flat roofs.

The reason you don't want to do it if the roof's visible is that turns an
icky color and stains from the junk in the air.

Do they use actual paint or the white stuff for mobile home roofs?

Hot Porch Roof
 

On Jul 26, 2:40 pm, Tony wrote:
Do they use actual paint or the white stuff for mobile home roofs?

Sort of. If they're doing it right, they're using "roof paint" (not
sure about the exact name). It's a thick, insulating, reflective
paint. I've seen it in white and silver at the local DIY stores. It
may come in other colors, but if heat is your main issue, you want one
of those two.

Now, of your roof is in good shape and you're just looking to reflect
more heat, there may be other options I'm not familiar with.

Hot Porch Roof
 

On Jul 26, 2:27 pm, Tony wrote:
Larry The Snake Guy wrote:
Not directly, but by conducting heat away from the sheathing, wouldn't
a properly placed fan lower the temperature of the sheathing thus
reducing the amount of heat it radiates?

I've considered ceiling fans but I don't know where I could properly
place them to do the job. I think ceiling fans would just blow hot air
all around me.

Yeah, ceiling fans without also insulating the roof probably wouldn't
help. I meant a fan/fans somewhere where they could blow/draw air
across the underside of the roof and out. That may not be possible
depending on the design of your roof, and is probably not your best
option by itself. I was just giving an example of how fans could
prevent radiant heating, in response to this statement: "A fan doesn't
stop *radiant* heat."

Hot Porch Roof
 

Foil is useless as condunctive insulation. Touching the hot
roof accomplishes nothing. The styrofoam could help.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"1D10T" wrote in message
...


1" Styrofoam, backed with aluminum foil, foil side up,
against the
sheathing. Cut it into strips, making a snug fit pressing
them between the
rafters. Available in 4 x 8 sheets. The white Styrofoam will
look good too.

Hot Porch Roof
 

"Stormin Mormon" wrote in message
...
Foil is useless as condunctive insulation. Touching the hot
roof accomplishes nothing. The styrofoam could help.

With the foil-side up it reflects the radiant heat. Perhaps I wasn't clear,
or you're not familiar with the product - the foil adheres to the Styrofoam.
I believe it's often used under vinyl siding.

"1D10T" wrote in message
...


1" Styrofoam, backed with aluminum foil, foil side up,
against the
sheathing. Cut it into strips, making a snug fit pressing
them between the
rafters. Available in 4 x 8 sheets. The white Styrofoam will
look good too.

Hot Porch Roof
 

Stormin Mormon wrote:
Foil is useless as condunctive insulation. Touching the hot
roof accomplishes nothing. The styrofoam could help.

Right. But it's 95% effective against radiant heat. You've got to have an
air-gap and circulation to remove the heat, but it's a cheap and effective
solution.

Hot Porch Roof
 

If you put the foil side "against the sheathing" then the
heat will conduct from the roof to the foil.

You could put the foil side under the rafters, facing in the
direction of the sheathing. It would also be a lot easier to
install, you don't have to cut the foam to shove it in
between the rafters.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"1D10T" wrote in message
...

With the foil-side up it reflects the radiant heat. Perhaps
I wasn't clear,
or you're not familiar with the product - the foil adheres
to the Styrofoam.
I believe it's often used under vinyl siding.

"1D10T" wrote in message
...


1" Styrofoam, backed with aluminum foil, foil side up,
against the
sheathing. Cut it into strips, making a snug fit pressing
them between the
rafters. Available in 4 x 8 sheets. The white Styrofoam
will
look good too.

Hot Porch Roof
 

With an air gap and air circulation, that's practical. But,
the "idiot" poster proposed cutting the foam board into
strips and packing it up against the roof.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"HeyBub" wrote in message
m...
Stormin Mormon wrote:
Foil is useless as condunctive insulation. Touching the
hot
roof accomplishes nothing. The styrofoam could help.

Right. But it's 95% effective against radiant heat. You've
got to have an
air-gap and circulation to remove the heat, but it's a cheap
and effective
solution.

Hot Porch Roof
 

on 7/26/2009 2:40 PM (ET) Tony wrote the following:
HeyBub wrote:
Tony wrote:
... and paint the roof white
I have been tempted! That part of the roof can not be seen from
ground level anyway.

If you can't see it, that's a good trick. It's often done on
commercial buildings with flat roofs.

The reason you don't want to do it if the roof's visible is that
turns an icky color and stains from the junk in the air.

Do they use actual paint or the white stuff for mobile home roofs?

Home Depot. 'Henry's Solarflex 287 SF'. Comes in a 5 gallon can. I don't
remember the price. I painted my 20' x20' black asphalt shingle sunroom
roof with it 2 years ago. It made a hell of a difference in the inside
temps. Well, maybe 'hell' is the wrong word. :-)
The roof is still white 2 years later.