| Author |
Flashing new roof to existing wall
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| J Geez 2006-06-25, 1:25 pm |
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Can someone explain to me the best practice for flashing a new low-sloped
(3:12) roof? The slope meets an existing vertical wall that has aluminum
siding. How do I integrate the step-flashing with the vertical wall (do I
need to remove alot of the existing siding)? Thank you.
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| tbasc@bellsouth.net 2006-06-25, 5:25 pm |
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J Geez wrote:
> Can someone explain to me the best practice for flashing a new low-sloped
> (3:12) roof? The slope meets an existing vertical wall that has aluminum
> siding. How do I integrate the step-flashing with the vertical wall (do I
> need to remove alot of the existing siding)? Thank you.
Flashing should have minimum 4" vertical leg.
Vertical leg should go between sheathing and weather barrier ( building
paper or wrap ).
Weather barrier should lap flashing 4".
Flashing should lap shingle style.
TB
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| J Geez 2006-06-25, 8:25 pm |
| The vertical wall is existing and already aluiminum sided. How do I get the
vertical leg of the flashing between the sheathing and the house wrap? Do I
cut the house wrap, slide the flashing under the house wrap then seal tape
the house wrap?
<tbasc@bellsouth.net> wrote in message
news:1151273309.931186.31990@c74g2000cwc.googlegroups.com...
>
> J Geez wrote:
>
> Flashing should have minimum 4" vertical leg.
> Vertical leg should go between sheathing and weather barrier ( building
> paper or wrap ).
> Weather barrier should lap flashing 4".
> Flashing should lap shingle style.
> TB
>
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| The leg should be under the siding but in this case I would
surface mount the flashing, 2-1/2" to 3" is plenty high with a
good silicone between the flashing and existing siding and then
*counter flash* it putting the top under the lap on the siding and
cut to the roof pitch at the bottom. Silicone both pieces will
hold them in but maybe use a few sheetmetal screws to suck them
tight. Another way, make them be their own counter flashing by
running each one up and under a lap on the siding. Not as neat
but will work.
Trying to cut that existing siding to get them where they properly
should be and you will have a real mess. Guaranteed.
"J Geez" <kpm3102@comcast.net> wrote in message
news:5ZednWcaXLG9kwLZnZ2dnUVZ_sednZ2d@comcast.com[color=darkred]
> The vertical wall is existing and already aluiminum
> sided. How do I get the vertical leg of the flashing
> between the sheathing and the house wrap? Do I cut the
> house wrap, slide the flashing under the house wrap then
> seal tape the house wrap?
> <tbasc@bellsouth.net> wrote in message
> news:1151273309.931186.31990@c74g2000cwc.googlegroups.com...
| |
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| "J Geez" <kpm3102@comcast.net> wrote in message
news:irSdnbz045h5KAPZnZ2dnUVZ_sCdnZ2d@comcast.com...
>
> Can someone explain to me the best practice for flashing a new low-sloped
> (3:12) roof? The slope meets an existing vertical wall that has aluminum
> siding. How do I integrate the step-flashing with the vertical wall (do I
> need to remove alot of the existing siding)? Thank you.
>
If you don't put the flashing behind the siding, water wash down the siding
will run behind the flashing. It will have better weatherseal than a rigged
version with silicon sealant and butting against the siding, and will hold
up against the weather much longer. Don't shortcut it.
--
Jonny
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| J Geez 2006-06-26, 3:25 am |
| Based on how the siding was cut away already to install the new roof
framing, I have about 2 and half inches of vertical wall exposure above the
roff deck so I should be able to get the flashing behind the siding, but is
it enough to just get it behind the siding? Just slip it behind the siding?
Would that be slipping it in behind the siding and then fastening the
flashing into the roof?
"J Geez" <kpm3102@comcast.net> wrote in message
news:irSdnbz045h5KAPZnZ2dnUVZ_sCdnZ2d@comcast.com...
>
> Can someone explain to me the best practice for flashing a new low-sloped
> (3:12) roof? The slope meets an existing vertical wall that has aluminum
> siding. How do I integrate the step-flashing with the vertical wall (do I
> need to remove alot of the existing siding)? Thank you.
>
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| Al Bundy 2006-06-26, 3:25 am |
| "J Geez" <kpm3102@comcast.net> wrote in
news:5ZednWcaXLG9kwLZnZ2dnUVZ_sednZ2d@comcast.com:
> The vertical wall is existing and already aluiminum sided. How do I
> get the vertical leg of the flashing between the sheathing and the
> house wrap? Do I cut the house wrap, slide the flashing under the
> house wrap then seal tape the house wrap?
>
> <tbasc@bellsouth.net> wrote in message
> news:1151273309.931186.31990@c74g2000cwc.googlegroups.com...
>
>
Just slip the vertical leg of the flashing under the aluminum siding
like 4" up the wall. If nails are in the way or there is a finishing
aluminum trim piece, remove and replace when done with nails of the same
material...probably aluminum.
If the siding is so close to the roof it's impossible to slip the
flashing under it, you need to cut the siding up slghtly. The flashing
NEEDS to be under the aluminum and stepped just as it is on the shingles.
The stepping will happen automatically since the flashing is 2" wider
(often 7" total) than the shingle exposure.
There is no need to caulk anything if done properly. A dab of roofing
cement on the nailhead of the roofing nails that goes through the
flashing is a good thing.
Unless you have access to a brake and bender, buying nice flat premade
flashing pieces is a big time saver and helps insure the end shingle lays
flat and seals. Maybe .25 a piece?
Al...
Professional Wanna-be...
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| Al Bundy 2006-06-26, 3:25 am |
| "J Geez" <kpm3102@comcast.net> wrote in
news:oqudnQuk5NdWyALZnZ2dnUVZ_oqdnZ2d@comcast.com:
> Based on how the siding was cut away already to install the new roof
> framing, I have about 2 and half inches of vertical wall exposure
> above the roff deck so I should be able to get the flashing behind the
> siding, but is it enough to just get it behind the siding? Just slip
> it behind the siding? Would that be slipping it in behind the siding
> and then fastening the flashing into the roof?
>
> "J Geez" <kpm3102@comcast.net> wrote in message
> news:irSdnbz045h5KAPZnZ2dnUVZ_sCdnZ2d@comcast.com...
>
>
> ... I have about 2 and half inches of vertical wall exposure
2 1/2"?! That means if you put standard premade flashing pieces (5"
vertical) your're only gonna have 2 1/2" under the siding. Not good but
it's still 5" above the roofline. But first thing that comes to my mind
is wind driven rain (hurricanes & severe t-storms) into the vertical
overlap of the exposed flashing and wind catching under the siding
pulling it out for periods. I personally would feel much better with a
strip of some type at the end of that siding running the lengh of the
siding edge to make sure it stays put. And with 2 1/2" of exposed
vertical overlap you just may wanna put some polyurathane where each
overlaps. A lot less aggrivation than trying to find/do later. Roofs
don't leak inside where the cause is outside. Purely unprofessional
observation and advice.
Al...
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| J Geez 2006-06-26, 3:25 am |
| Do you know what the minimum exposure is? I think I read one and half inch
should be revealed from the siding to the shingle. I probably will have
more exposure than that and maybe the siding crew for the addition can do
something to fix that up for me.
"Al Bundy" <postmaster@127.0.0.1> wrote in message
news:Xns97EE1218756C2AlBundy@216.196.97.142...
> "J Geez" <kpm3102@comcast.net> wrote in
> news:oqudnQuk5NdWyALZnZ2dnUVZ_oqdnZ2d@comcast.com:
>
>
>
>
> 2 1/2"?! That means if you put standard premade flashing pieces (5"
> vertical) your're only gonna have 2 1/2" under the siding. Not good but
> it's still 5" above the roofline. But first thing that comes to my mind
> is wind driven rain (hurricanes & severe t-storms) into the vertical
> overlap of the exposed flashing and wind catching under the siding
> pulling it out for periods. I personally would feel much better with a
> strip of some type at the end of that siding running the lengh of the
> siding edge to make sure it stays put. And with 2 1/2" of exposed
> vertical overlap you just may wanna put some polyurathane where each
> overlaps. A lot less aggrivation than trying to find/do later. Roofs
> don't leak inside where the cause is outside. Purely unprofessional
> observation and advice.
>
> Al...
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| Al Bundy 2006-06-29, 9:26 am |
| "J Geez" <kpm3102@comcast.net> wrote in
news:V7GdneiXx7pT5QLZnZ2dnUVZ_vKdnZ2d@comcast.com:
> Do you know what the minimum exposure is? I think I read one and half
> inch should be revealed from the siding to the shingle. I probably
> will have more exposure than that and maybe the siding crew for the
> addition can do something to fix that up for me.
>
> "Al Bundy" <postmaster@127.0.0.1> wrote in message
> news:Xns97EE1218756C2AlBundy@216.196.97.142...
>
>
>
> Do you know what the minimum exposure is?
No, not really. Not any spec anyway. I'm not a roofer. Just a
Professional Wanna-be. But I would think you want something so water
doesn't get trapped in there in winter and freeze.
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