I'm working on a project to replace the bottom 20" of t1-11 type
siding on my house. I cut and stained new 20" sheets (including edge
staining). I cut off the bottom 20" of siding from the house. I
stained the new cut edge. I slipped z-flashing under that new cut
edge and nailed it in place through the siding about 1 3/4" above the
cut edge (the back edge of the flashing is 2" tall). I left a 1/8"
gap between the new cut edge and the flashing (so that panels are
separated by 1/8"). And finally I slipped the new panels into place
and nailed them in with galvanized ring shank 8d framing nails.

I finished this yesterday on a wall and then we had a massively
torrential rain last night. Today I went and looked at it (this is a
wall in the garage so I can see the other side of the wall too).
There is dampness on the back edge of the siding just above the back
edge of the z-flashing. Not everywhere but in some places. Back
outside I looked at the flashing and you can see some water still
sitting in the groove.

Is this normal? One thing that is true is that the existing siding is
*badly* in need of new stain, so it could be wicking in above the new
cut edge which I stained. But it seems most logical to me that water
is sitting on the flashing and wicking up into the wood.

The flashing profile is 90 degree angles. It seems like it should be
a little less so that water is encouraged to run out. I can try and
bend it a little bit on subsequent walls.

Needless to say I'm disappointed. I guess one question is whether the
flashing is supposed to keep the water out completely or simply
provide an avenue for it to get out and evaporate?

thx

The flashing profile is 90 degree angles. *It seems like it should be
a little less so that water is encouraged to run out. *I can try and
bend it a little bit on subsequent walls.

I got another look at it tonight while it was pouring. The problem is
definitely that water is sitting on the flashing and not running out
on its own, thus it wicks up into the siding above it. I tried
tapping down the flashing at each groove but it doesn't look like it's
enough to make a big difference.

I'm thinking that on the next wall I should install the flashing with
a 1/8" gap in the back and then try to bend the front down another
1/8" and then install the lower siding panel up to that front edge, so
that there is a downward profile on the flashing. Thoughts?

As for the two walls I've already done...sigh. The last thing I want
to do is re-do them, but we'll see. Any ideas on how to repair this
without tearing it apart are appreciated.

"ben" wrote in message
...

The flashing profile is 90 degree angles. It seems like it should be
a little less so that water is encouraged to run out. I can try and
bend it a little bit on subsequent walls.

I got another look at it tonight while it was pouring. The problem is
definitely that water is sitting on the flashing and not running out
on its own, thus it wicks up into the siding above it. I tried
tapping down the flashing at each groove but it doesn't look like it's
enough to make a big difference.

I'm thinking that on the next wall I should install the flashing with
a 1/8" gap in the back and then try to bend the front down another
1/8" and then install the lower siding panel up to that front edge, so
that there is a downward profile on the flashing. Thoughts?

As for the two walls I've already done...sigh. The last thing I want
to do is re-do them, but we'll see. Any ideas on how to repair this
without tearing it apart are appreciated.

No ideas without tearing it apart.

I would have at _least_ 3/8" gap between the upper panel & z flashing. The
bottom panel should be tight with the z flashing. Also, did you overlap
your flashing strips? A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

I'm not very much of a fan with the z flashing being used on siding. Ive
seen too much rot, because of improper installation. I prefer to see siding
overlapped by 2". I think it looks better, and does a superior job to the
flashing, as long as you stagger your T1-11 so the seams are not on top of
each other. Check it out on your other siding you need to do.

I would have at _least_ 3/8" gap between the upper panel & z flashing. The
bottom panel should be tight with the z flashing. Also, did you overlap
your flashing strips? A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

I chose 1/8" based on a This Old House page (http://
http://www.thisoldhouse.com/toh/askt...064764,00.html) that
suggested a gap between 1/8 and 1/4. Clearly I erred on the small end
of things. I did overlap my flashing at least 2" but did not caulk on
the overlap. The bottom panel is tight with the flashing and I
applied a bead of caulk on top of the bottom piece where it butts
against the flashing. The bottom piece looks very dry.

What do you think about installing it with a larger gap say 3/8" like
you suggest and then bending the flashing just a bit so that it slopes
downward (the high point being behind the siding and the low point in
front of the siding)? The benefit is that it would guide the water
more easily out of the channel. The downside is that the bottom piece
can't fit as tightly against the flashing since the flashing won't be
at a 90 degree angle.


I'm not very much of a fan with the z flashing being used on siding. Ive
seen too much rot, because of improper installation. I prefer to see siding
overlapped by 2". *I think it looks better, and does a superior job to the
flashing, as long as you stagger your T1-11 so the seams are not on top of
each other. Check it out on your other siding you need to do.

So you mean treat the t1-11 like lap siding?

thanks!

Cabot wrote:
"ben" wrote in message
...

The flashing profile is 90 degree angles. It seems like it should be
a little less so that water is encouraged to run out. I can try and
bend it a little bit on subsequent walls.

I got another look at it tonight while it was pouring. The problem is
definitely that water is sitting on the flashing and not running out
on its own, thus it wicks up into the siding above it. I tried
tapping down the flashing at each groove but it doesn't look like it's
enough to make a big difference.

I'm thinking that on the next wall I should install the flashing with
a 1/8" gap in the back and then try to bend the front down another
1/8" and then install the lower siding panel up to that front edge, so
that there is a downward profile on the flashing. Thoughts?

As for the two walls I've already done...sigh. The last thing I want
to do is re-do them, but we'll see. Any ideas on how to repair this
without tearing it apart are appreciated.

No ideas without tearing it apart.

I would have at _least_ 3/8" gap between the upper panel & z flashing. The
bottom panel should be tight with the z flashing. Also, did you overlap
your flashing strips? A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

I'm not very much of a fan with the z flashing being used on siding. Ive
seen too much rot, because of improper installation. I prefer to see siding
overlapped by 2". I think it looks better, and does a superior job to the
flashing, as long as you stagger your T1-11 so the seams are not on top of
each other. Check it out on your other siding you need to do.





???? Exactly how would he overlap it in this application? I have seen
overlapped T1-11 on gables, but that requires furring out the gable, or
adding another layer of sheathing up there before applying the siding,
or (on new construction) actually framing the gable 5/8" (ot whatever)
proud of the lower wall. But on a retrofit like this, I don't see how he
would get the lower panel up under the upper panel without it looking
like crap. T1-11 won't flare like horizontal wood siding. Even on
gables, I have never seen a tight overlap- there was always a strip of
wood up in there for the bottom nailer for the top panel, slightly
thicker than the siding, so as to not provide a crack that would wick
water and keep the ends of both panels wet in a heavy rain. (as well as
providing an insect block.)

I'm no siding expert, but I think OP is gonna end up pulling the first
two walls apart and doing it over, for a reliable cure. It is the only
way to be sure, and not always be worried every time it rains.

--
aem sends...

"aemeijers" wrote in message
...
Cabot wrote:
???? Exactly how would he overlap it in this application? I have seen
overlapped T1-11 on gables, but that requires furring out the gable, or
adding another layer of sheathing up there before applying the siding, or
(on new construction) actually framing the gable 5/8" (ot whatever) proud
of the lower wall. But on a retrofit like this, I don't see how he would
get the lower panel up under the upper panel without it looking like
crap. T1-11 won't flare like horizontal wood siding. Even on gables, I
have never seen a tight overlap- there was always a strip of wood up in
there for the bottom nailer for the top panel, slightly thicker than the
siding, so as to not provide a crack that would wick water and keep the
ends of both panels wet in a heavy rain. (as well as providing an insect
block.)

I've seen it done, and I've done it. Won't flare? Depends on what you call
flare. I'm gonna have to take a couple of pictures and post them. Just
because you've never seen something done, doesn't mean it can't be done.
In fact, I'll attempt to grab a picture with where T1-11 has a 4' panel,
followed by a overlapped bandboard of T1-11, followed by a full panel,
followed by a gable end...... All overlapped. So flagged this thread,
because it may be a couple of days b/4 I will get a picture.

Retrofit, you pull fasteners, pretty much the same way you have to do, in
order to get flashing under it. It's not really difficult to figure out.
Your nonsense about furring out, is just that, nonsense. T1-11 is only so
thick, exactly what size fur strips would someone use to fur a 1/2" or
5/8"? Ok, maybe 3/8" lathe, but it could be so high, otherwise it will kick
the siding out further than without. Think about that one. Also, you never
put a trim strip at the bottom of overlapped siding, talk about a water
trap! Geesh.

"ben" wrote in message
...



I chose 1/8" based on a This Old House page (http://
http://www.thisoldhouse.com/toh/askt...064764,00.html) that
suggested a gap between 1/8 and 1/4. Clearly I erred on the small end
of things. I did overlap my flashing at least 2" but did not caulk on
he overlap. The bottom panel is tight with the flashing and I
applied a bead of caulk on top of the bottom piece where it butts
against the flashing. The bottom piece looks very dry.
What do you think about installing it with a larger gap say 3/8" like
you suggest and then bending the flashing just a bit so that it slopes
downward (the high point being behind the siding and the low point in
front of the siding)? The benefit is that it would guide the water
more easily out of the channel. The downside is that the bottom piece
can't fit as tightly against the flashing since the flashing won't be
at a 90 degree angle.

Certainly sealing the overlapped pieces is a must, since it is a horizontal
plane. I understand what you're trying to accomplish by rebending or
distorting the flashing, however, when the upper piece of siding is tight,
the "flare" will also be gone. Give it a try, who knows? You already know
why I would have a 3/8" gap, because water will find its way, it going to
wick as long as its raining. LOL, of course that is the problem!

So you mean treat the t1-11 like lap siding?

Exactly

Cabot wrote:
"aemeijers" wrote in message
...
Cabot wrote:
???? Exactly how would he overlap it in this application? I have seen
overlapped T1-11 on gables, but that requires furring out the gable, or
adding another layer of sheathing up there before applying the siding, or
(on new construction) actually framing the gable 5/8" (ot whatever) proud
of the lower wall. But on a retrofit like this, I don't see how he would
get the lower panel up under the upper panel without it looking like
crap. T1-11 won't flare like horizontal wood siding. Even on gables, I
have never seen a tight overlap- there was always a strip of wood up in
there for the bottom nailer for the top panel, slightly thicker than the
siding, so as to not provide a crack that would wick water and keep the
ends of both panels wet in a heavy rain. (as well as providing an insect
block.)

I've seen it done, and I've done it. Won't flare? Depends on what you call
flare. I'm gonna have to take a couple of pictures and post them. Just
because you've never seen something done, doesn't mean it can't be done.
In fact, I'll attempt to grab a picture with where T1-11 has a 4' panel,
followed by a overlapped bandboard of T1-11, followed by a full panel,
followed by a gable end...... All overlapped. So flagged this thread,
because it may be a couple of days b/4 I will get a picture.

Retrofit, you pull fasteners, pretty much the same way you have to do, in
order to get flashing under it. It's not really difficult to figure out.
Your nonsense about furring out, is just that, nonsense. T1-11 is only so
thick, exactly what size fur strips would someone use to fur a 1/2" or
5/8"? Ok, maybe 3/8" lathe, but it could be so high, otherwise it will kick
the siding out further than without. Think about that one. Also, you never
put a trim strip at the bottom of overlapped siding, talk about a water
trap! Geesh.



I didn't say trim strip. Read it again. I said a thin board way up in
the crack (above the top edge of the lower panel), essentially a
horizontal furring strip. Plywood tightly lapped over plywood in a wet
environment will wick water- the overlapped part needs a gap to stay
dry. I've seen plenty of t1-11 gables done exactly as I described, and
with the upper panel hanging in air slightly in front of the lower
panel, it dries out quickly and doesn't rot.

Post your pictures somewhere, and put a link back here. I'll look at
them. But I can't see how such an installation could look decent.

--
aem sends...

On 2009-07-09, ben wrote:

As for the two walls I've already done...sigh. The last thing I
want to do is re-do them, but we'll see. Any ideas on how to repair
this without tearing it apart are appreciated.

If you decide that you want a 3/8" gap instead of a 1/8" gap, with
very careful use of the circular saw you could trim the upper panel in
place to remove 1/4" of it. You'd need to set your circular shy of
the depth of the panel, so you don't hit the Z-flashing, and you could
finish up with a sharp utility knife. With a 3/8" gap you should be
able to get a small brush in there to seal the new cut.

Cheers, Wayne

"aemeijers" wrote in message
...
Cabot wrote:
"aemeijers" wrote in message
...
Cabot wrote:
???? Exactly how would he overlap it in this application? I have seen
overlapped T1-11 on gables, but that requires furring out the gable, or
adding another layer of sheathing up there before applying the siding,
or (on new construction) actually framing the gable 5/8" (ot whatever)
proud of the lower wall. But on a retrofit like this, I don't see how
he would get the lower panel up under the upper panel without it
looking like crap. T1-11 won't flare like horizontal wood siding. Even
on gables, I have never seen a tight overlap- there was always a strip
of wood up in there for the bottom nailer for the top panel, slightly
thicker than the siding, so as to not provide a crack that would wick
water and keep the ends of both panels wet in a heavy rain. (as well as
providing an insect block.)

I didn't say trim strip. Read it again. I said a thin board way up in the
crack (above the top edge of the lower panel), essentially a horizontal
furring strip. Plywood tightly lapped over plywood in a wet environment
will wick water- the overlapped part needs a gap to stay dry. I've seen
plenty of t1-11 gables done exactly as I described, and with the upper
panel hanging in air slightly in front of the lower panel, it dries out
quickly and doesn't rot.

I read it again, about the "slightly thicker than the siding". Hello? This
is a catch for water, I've seen plenty of rotted siding because nobody
cares what happens 15 yrs down the road. I really shouldn't have to tell
you, anything fastened horizontally, is going to be a water catch.Thats the
problem doing something, because everyone else does it. I call BS that it
doesn't rot, I've seen those jobs, which were done as new construction.
Slam, bam, thank you mam, give me my money, I'm gone.


Post your pictures somewhere, and put a link back here. I'll look at
them. But I can't see how such an installation could look decent.

LOL, I'm not asking for your approval. I'll post a link, and I know this
has been on the structure for 19 yrs, no rot, no wicking, no problems. And,
is more attractive than Z strips, and eliminates the problems which come
with using Z strips.

I like how you're defending the plenty of jobs done this way. LOL, kinda
tells all.

If you decide that you want a 3/8" gap instead of a 1/8" gap, with
very careful use of the circular saw you could trim the upper panel in
place to remove 1/4" of it. *You'd need to set your circular shy of
the depth of the panel, so you don't hit the Z-flashing, and you could
finish up with a sharp utility knife. *With a 3/8" gap you should be
able to get a small brush in there to seal the new cut.

Thanks for that suggestion. I have been thinking about that option.
I could screw a guide onto the wall to help me keep it straight. But
the trick really is not cutting the flashing. The wall is definitely
not perfectly flat, so there will be a spot here or there where I
either don't go deep enough or go too deep.

Meanwhile, I've been Googling this issue and find there is wide
variation in recommendations. Credible sources suggest the gap should
be anywhere from 0 to 3/8" or bigger. These sources include a book on
Modern Carpentry that I have (0"), Tom Silva from TOH (1/8 to 1/4"),
Hardieboard installation instructions (1/4" with a sloped flashing), a
UMass prof from the center for building tech (1/4+"), and a book by
the head of the Wood Building Research Center (3/8" or bigger
depending on the moisture of the siding at installation).

Quite interesting. Intuitively the 0 gap makes sense because the
water would just run right off, but I know from experience (e.g. the
rest of the siding on the house) that a 0 gap results in wet siding
over the years. That's one of the primary failure points on the
house. So if a 0 gap doesn't work, then bigger seems better to me,
backing up Cabot's 3/8".

I've decided to just build my own little tiny test wall to verify 3/8"
will work for me. I've got the wall built. Now I need to seal up the
back with plastic and set the whole thing in front of the hose for
half an hour and see what happens to the back of it.

"aemeijers" wrote in message
...

Post your pictures somewhere, and put a link back here. I'll look at
them. But I can't see how such an installation could look decent.

Here are some links. Its funny how people talk about insect infestation
with wood, but with aluminum or vinyl siding are not worried. Insects will
get behind aluminum/vinyl siding a lot easier than most wood. You make an
insect block like with any other wood. The link fascia/groove detail shows
how you block it, or there's a different way when installing new. But, I'm
not giving out all my secrets, it took a lot of asking and looking over
jobs, to see what is best against weather infiltration.

Northside
http://s132.photobucket.com/albums/q...=Northside.jpg

Southside
http://s132.photobucket.com/albums/q...=Southside.jpg

Band detail
http://s132.photobucket.com/albums/q...Banddetail.jpg

Fascia / Groove detail
http://s132.photobucket.com/albums/q...oovedetail.jpg

Rear view
http://s132.photobucket.com/albums/q...t=RearView.jpg

A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

Sealant = caulk? Or something else?

Great photos. Your install looks great.

"ben" wrote in message
...
A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

Sealant = caulk? Or something else?

Great photos. Your install looks great.

Thanks, that was done 19 years ago, the photos were today.

For overlapping of the Z flash, I would use gutter goop or similar, or a
quality caulk.

ben wrote:
A 2" overlap should be minimum, with sealant applied
with the overlapping pieces.

Sealant = caulk? Or something else?

Great photos. Your install looks great.

Hard to tell from the pictures, due to the wide-angle lens, but that
sure looks like a stepped wall to me. I don't see any angle to the
siding at all, which an overlap on a flat wall would create. I'd be
curious what a long straightedge held against that wall would show. It
does look well-sealed. How long does whatever it is sealed with last
before it needs refreshing? And what is the climate like there?

--
aem sends...

"aemeijers" wrote in message
...

Hard to tell from the pictures, due to the wide-angle lens, but that sure
looks like a stepped wall to me. I don't see any angle to the siding at
all, which an overlap on a flat wall would create. I'd be curious what a
long straightedge held against that wall would show. It does look
well-sealed. How long does whatever it is sealed with last before it
needs refreshing? And what is the climate like there?

No stepped wall. I've probably done a dozen of these homes built by
different builders. All of them in the 12-13 yr old range, done because of
rotted siding. I know how builders build, especially cookie cutters. Its
for the most cost efficient way. I never held any carpenter responsible for
following specs, its something they _must_ do.

The straight edge would just follow the taper. Now if you held a 6' level,
I'm sure the bubble wont be centered, but then again, being a cookie
cutter, I doubt there are any plumb walls in this place.

The last time this house was done, was about 10 yrs ago, when it got a
color change. As far as sealing it up, it was the best SW had to offer, I'm
talking an initial investment of $10 for 2 tubes of 50 yr stuff, which I
ended pitching the left over. When it got color changed, I bought a tube
and touched up a few areas. Low maintenance IMHO, if you like T1-11, then
many people don't.

Climate: Midwest with extreme temperature swings, near Lake Erie. Lots of
snow, rain, sleet, wind, & heat.

For overlapping of the Z flash, I would use gutter goop or similar, or a
quality caulk.

Cabot,

I built a test wall with a 3/8" gap and doused it with the hose for a
long time. Not a drop on the inside! You can literally see the
difference between 3/8 and 1/8. On the 3/8 wall, the water runs down
the wall, into the flashing gap, and out of it. With 1/8" the water
runs down the wall, but water sits and stays in the flashing gap.

So I went out yesterday and carefully trimmed a 1/4" off the upper
piece like Wayne suggested. I then stained the new edge.

While I was there I went ahead and put a coat of stain on the flashing
(could hardly help it anyway). But today it occurred to me that I
should check if having paint or stain on the flashing matters. Does
it? Is there any problem having stain on there?

Thanks for all your help!

"ben" wrote in message
...


For overlapping of the Z flash, I would use gutter goop or similar, or a
quality caulk.

Cabot,

I built a test wall with a 3/8" gap and doused it with the hose for a
long time. Not a drop on the inside! You can literally see the
difference between 3/8 and 1/8. On the 3/8 wall, the water runs down
the wall, into the flashing gap, and out of it. With 1/8" the water
runs down the wall, but water sits and stays in the flashing gap.

So I went out yesterday and carefully trimmed a 1/4" off the upper
piece like Wayne suggested. I then stained the new edge.

While I was there I went ahead and put a coat of stain on the flashing
(could hardly help it anyway). But today it occurred to me that I
should check if having paint or stain on the flashing matters. Does
it? Is there any problem having stain on there?

Thanks for all your help!

I would say it matters, only if the stain somehow diverts the water, and
holds it so moisture can wick. Otherwise, it won't hurt the flashing strip.

Glad you got the problem remedied!

On Jul 11, 3:22*pm, "Cabot" wrote:
"ben" wrote in message

...





For overlapping of the Z flash, I would use gutter goop or similar, or a
quality caulk.

Cabot,

I built a test wall with a 3/8" gap and doused it with the hose for a
long time. *Not a drop on the inside! *You can literally see the
difference between 3/8 and 1/8. *On the 3/8 wall, the water runs down
the wall, into the flashing gap, and out of it. *With 1/8" the water
runs down the wall, but water sits and stays in the flashing gap.

So I went out yesterday and carefully trimmed a 1/4" off the upper
piece like Wayne suggested. *I then stained the new edge.

While I was there I went ahead and put a coat of stain on the flashing
(could hardly help it anyway). *But today it occurred to me that I
should check if having paint or stain on the flashing matters. *Does
it? *Is there any problem having stain on there?

Thanks for all your help!

I would say it matters, only if the stain somehow diverts the water, and
holds it so moisture can wick. Otherwise, it won't hurt the flashing strip.

Glad you got the problem remedied!

Cabot,

Just had our first bigtime soaker rain. Unfortunately the problem
doesn't seem to be completely gone, although it's clearly a lot better
than it was. Instead of the wood being soaked everywhere on the
backside and up about 2-3" from the cut edge, now it's wet in an
occasional spot, and not as high. I can only see about 4' of this
wall from the inside before it's covered with drywall.

I went outside with a flashlight and umbrella. I don't know if I
caught the worst of it, but what I did see looked like my test
wall...the water was not filling the flashing gap. So I'm wondering
if I should be cutting it higher (it's a bit over 3/8" gap now) or
maybe just need another coat of stain on the cut edge? Because it's
already up I can't stain the backside at all.

Thanks for any advice.

On Jul 15, 7:05*am, ben wrote:
On Jul 11, 3:22*pm, "Cabot" wrote:



"ben" wrote in message

...

For overlapping of the Z flash, I would use gutter goop or similar, or a
quality caulk.

Cabot,

I built a test wall with a 3/8" gap and doused it with the hose for a
long time. *Not a drop on the inside! *You can literally see the
difference between 3/8 and 1/8. *On the 3/8 wall, the water runs down
the wall, into the flashing gap, and out of it. *With 1/8" the water
runs down the wall, but water sits and stays in the flashing gap.

So I went out yesterday and carefully trimmed a 1/4" off the upper
piece like Wayne suggested. *I then stained the new edge.

While I was there I went ahead and put a coat of stain on the flashing
(could hardly help it anyway). *But today it occurred to me that I
should check if having paint or stain on the flashing matters. *Does
it? *Is there any problem having stain on there?

Thanks for all your help!

I would say it matters, only if the stain somehow diverts the water, and
holds it so moisture can wick. Otherwise, it won't hurt the flashing strip.

Glad you got the problem remedied!

Cabot,

Just had our first bigtime soaker rain. *Unfortunately the problem
doesn't seem to be completely gone, although it's clearly a lot better
than it was. *Instead of the wood being soaked everywhere on the
backside and up about 2-3" from the cut edge, now it's wet in an
occasional spot, and not as high. *I can only see about 4' of this
wall from the inside before it's covered with drywall.

I went outside with a flashlight and umbrella. *I don't know if I
caught the worst of it, but what I did see looked like my test
wall...the water was not filling the flashing gap. *So I'm wondering
if I should be cutting it higher (it's a bit over 3/8" gap now) or
maybe just need another coat of stain on the cut edge? *Because it's
already up I can't stain the backside at all.

Thanks for any advice.

I've always found it curious that even the manufacturers don't call
out how big of a gap should be at the Z-flashing. I've seen it butted
tight (aka siding death) and with a pretty wide range of gaps.
Generally as long as the gap is large enough to get a brush in there
and verify visually that the edges are getting sealed and not
delaminating, that's enough of a gap. I usually install plywood
siding with 1/4"+ gap...at least I did. Now I use different details
to cover up the Z-flashing.

Another poster mentioned overlapping the plywood siding, and the
pictures certainly look nice enough. That is a superior way to do it
for maintenance as you can readily verify that the plywood edges are
sealed adequately and easily reapply paint/stain. That being said,
Aemijiers has a point about the flare in the siding. If the plywood
siding is the structural wall sheathing, it presents problems. The
flare would have gaps between the plywood and the framing and building
inspectors don't like to see gaps in structural work. Siding nails
don't have a lot of excess strength and deform easily. They must be
pulling the sheathing tight to the framing without any gaps. It is
not a big deal to remedy that, as an undercourse cedar shingle stapled/
nailed to each stud is cheap and fast enough and takes care of the
taper.

As far as your situation, I hope you were careful to not nick the Z-
flashing if it is the thin aluminum stuff. A score in the aluminum
from a knife weakens it, and depending on the exposure, can crack with
repeated expansion from temperature swings and sun.

You may want to apply a wood preservative on the cut plywood edges and
apply the stain prior to installing the Z-flashing. That's the best
way to insure complete coverage and prevent problems down the road.
You can also pre-bend the Z-flashing a bit to provide a little slope
so water won't sit on it. Since the flashing is well below eye level
having dead straight flashing isn't so critical. Take it easy and bend
a little bit at a time and see how it looks before installing the
lower piece of siding.

R

On Jul 15, 6:05*am, ben wrote:

Just had our first bigtime soaker rain. *Unfortunately the problem
doesn't seem to be completely gone, although it's clearly a lot better
than it was. *Instead of the wood being soaked everywhere on the
backside and up about 2-3" from the cut edge, now it's wet in an
occasional spot, and not as high. *I can only see about 4' of this
wall from the inside before it's covered with drywall.

I went outside with a flashlight and umbrella. *I don't know if I
caught the worst of it, but what I did see looked like my test
wall...the water was not filling the flashing gap. *So I'm wondering
if I should be cutting it higher (it's a bit over 3/8" gap now) or
maybe just need another coat of stain on the cut edge? *Because it's
already up I can't stain the backside at all.


Consider the possibility that with the bigger gap any blowing rain can
now hit the flashing and bounce upward into the upper paneling. If
this is happening, a bigger gap will likely increase your problem
rather than lessen it.

KC

As far as your situation, I hope you were careful to not nick the Z-
flashing if it is the thin aluminum stuff. *A score in the aluminum
from a knife weakens it, and depending on the exposure, can crack with
repeated expansion from temperature swings and sun.

You may want to apply a wood preservative on the cut plywood edges and
apply the stain prior to installing the Z-flashing. *That's the best
way to insure complete coverage and prevent problems down the road.
You can also pre-bend the Z-flashing a bit to provide a little slope
so water won't sit on it. *Since the flashing is well below eye level
having dead straight flashing isn't so critical. Take it easy and bend
a little bit at a time and see how it looks before installing the
lower piece ofsiding.

R, thanks for the info.

There's no question that I did cut into the z-flashing with my utility
knife when trimming off the 1/4" piece. I know I didn't go through
it, but it was impossible to trim that piece off without getting into
it a little bit. Afterward I stained the new edge and that stain
ended up filling the score marks on the flashing. I was hoping that
might help.

I was definitely pre-staining the edges before I assembled. It's just
that on this wall in trying to fix it after the fact that I ended up
staining in the gap.

I'm wondering about the possibility of getting some oil-based primer
on that edge, then staining again. ANy problem with trying that? Seem
worth the trouble? I'm still trying to keep from redoing this wall.

KC suggested that water may be bouncing upward in a blowing rain.
That suggests that going bigger on the gap isn't a good plan. I don't
have any lumber behind this joint (except for studs) so there's
nothing backing the joint that holds the back end of the flashing
against the panel. Not that it flares out badly, but in a few spots
it comes away a tiny bit. However, it's not like these spots are the
only places with trouble.

On Jul 15, 3:06*pm, ben wrote:

R, thanks for the info.

There's no question that I did cut into the z-flashing with my utility
knife when trimming off the 1/4" piece. *I know I didn't go through
it, but it was impossible to trim that piece off without getting into
it a little bit. *Afterward I stained the new edge and that stain
ended up filling the score marks on the flashing. *I was hoping that
might help.

Sorry, stain is not a sealant. There was another guy who was working
on his house and he had a tendency to get into a jamb while working on
something, then ask his questions how to get out of it. I'd cringe
every time I'd see his name starting a new thread. Ask your questions
first and you'll get help avoiding these problems - a far cheaper and
less frustrating way to go!

I was definitely pre-staining the edges before I assembled. *It's just
that on this wall in trying to fix it after the fact that I ended up
staining in the gap.

As long as you are taking care and paying attention while sealing the
cut edges it shouldn't be a problem. It's when you get cowboy
painters blowing through the job that you run into problems.

I'm wondering about the possibility of getting some oil-based primer
on that edge, then staining again. *ANy problem with trying that? Seem
worth the trouble? *I'm still trying to keep from redoing this wall.

Lots of painters like the oil base primer, but I'm a fan of a wood
preservative (long as it's not Thompson's). Let it dry and you won't
have adhesion problems whether you decide to oil prime or just stain.

KC suggested that water may be bouncing upward in a blowing rain.
That suggests that going bigger on the gap isn't a good plan. *I don't
have any lumber behind this joint (except for studs) so there's
nothing backing the joint that holds the back end of the flashing
against the panel. *Not that it flares out badly, but in a few spots
it comes away a tiny bit. *However, it's not like these spots are the
only places with trouble.

The surface tension of water, and the wicking action of wood is what
kills the end grain. In a rain with little or no wind your siding
will get plenty wet and the water will run down until it hits the
bottom edge of the plywood. Before the water droplets take that death
defying leap off of the edge, they look for an easier way down due to
surface tension. They'll run back along that cut edge and if there
are any unsealed voids the end grain will suck up the water. Water
doesn't have to bounce up onto the underside.

Not having any blocking behind the flashing is tough. It sounds like
you've been doing your homework, so I'm sure you've run across the APA
303 specs with the nifty little pictures that show the blocking behind
the flashing to prevent the problem you're experiencing (and allowing
the horizontal edges of the plywood to be fully nailed off to take
care of the shear load). You pretty much have to pre-bend the
flashing to provide a bit of an outward slope so the flashing sheds
water more readily. In your situation I'd have considered using
heavier aluminum trim coil and bent up some flashing on a brake so
there'd be nice straight lines and the pitch would be built in.

In construction when you run into a problem, and you've done some of
the work and backed yourself into a corner, you sometimes have to take
a step back to go forward. Before you take any steps, forward or
backward, ask somebody for directions. All of this stuff is a
learning process. You can either find out the problems on your own
and on your own dollar, or let some people tell you some war stories.
Have fun with it.

R

Lots of painters like the oil base primer, but I'm a fan of a wood
preservative (long as it's not Thompson's). *Let it dry and you won't
have adhesion problems whether you decide to oil prime or just stain.

So you're talking about something like Thompson's, just not that
brand? Will that go on without issue on the edge that already has the
stain? Then it sounds like you're saying I can stain over it without
ruining it's preservative properties?

care of the shear load). *You pretty much have to pre-bend the
flashing to provide a bit of an outward slope so the flashing sheds
water more readily. *In your situation I'd have considered using
heavier aluminum trim coil and bent up some flashing on a brake so
there'd be nice straight lines and the pitch would be built in.

Is there any way to pre-bend the flashing without a brake? I tried by
hand and couldn't do it. Well, not on a long piece anyway. It's easy
on a short piece.

Have fun with it.

I'm trying and having some success

I did some more testing this afternoon. I wanted to make sure I could
reproduce the problem with my hose, which I can. So I took the hose
to my test wall that I built before the most recent phase, and no
matter what I did I couldn't make it have the same problem. Here are
the differences between my real wall and the test wall:

1. the real wall's flashing has a light coat of stain on it
2. the real wall does not have stain up the back side of the cut panel
(test has up about 1")
3. the real wall's flashing is, in some places, just barely angled
upward at the front because I shoved the lower panels up against it a
little too tight when nailing them in
4. the real wall's upper panel face needs stain badly

I don't think the last one is the culprit because the backside doesn't
get wet anywhere other than the edge. I also doubt that #1 is the
culprit, although it could be that the stained flashing doesn't shed
water as well as the unstained flashing. But I'll always need to get
in that gap and restain the edge over the years so I'm not sure how I
avoid it (not to mention it looks better to 'hide' it with some
stain).

That leaves #2 (no stain on backside) and #3 (flashing angle). If I
tore it apart I could do #2 fairly well even though that upper panel
is in place. I could even get a little under the studs since I'm
prying/cutting any nails on the bottom several inches to get the
flashing up there. On my test wall the upper panel was from a scrap I
stained before installing so it's stained nicely on the back 1" or
so. #3 also seems like a contributor. I had hoped it wouldn't be
enough to matter, but maybe it is. My test wall doesn't have the
flashing angled bent down at all and I'm not having the problem there.

I'd like to save what I've done so far, though if that's not possible
I'm ok with it. Frankly I'd be happy to tear it all apart and start
over if I could be sure the next iteration would work. It sounds like
my first attempt should be some wood preservative on the edge. If
that doesn't work, then I'm probably looking at tearing off and
starting over with 1) staining and preserving a bit up the backside as
much as possible, 2) pre-bending the flashing or at least not
unintentionally bending it the wrong way, 3) continue with the 3/8"
gap, 4) consider some blocking behind the cut edge.

For that blocking, I presume we're talking about 2x4s toe nailed so
that their short edge is behind the cut edge for nailing. Actually,
above the cut edge a bit so that I'm not nailing through the flashing,
so up 1.5" from the cut edge?

Thanks R and everyone else!

"ben" wrote in message
...


Thanks R and everyone else!

Let us know how you remedy the situation.

It nice you're able to see behind the siding, if only in one place, there
is a problem.

I could believe it the same reason, T1-11 rots prematurely around here.
Only nobody knows there is a problem, because they can't see the backside.

In any event, I said from the beginning I'm not a big fan of the z strip
for this purpose. I'm sure it could be alright, but rarely are panels
stained b/4 they are put up. I have to "LOL" at myself, I tried it to stain
the entire panel b/4 putting them up. I found out you never let the sun hit
the panel b/4 it goes up, while still wet. I found out the panels take a
banana shape, only worse. 8-)

It nice you're able to see behind thesiding, if only in one place, there
is a problem.

I could believe it the same reason,T1-11rots prematurely around here.
Only nobody knows there is a problem, because they can't see the backside.

Indeed. I started on the back wall of the garage figuring I'd work
out all the kinks there. What I didn't think about is that it has a
bit of a roof overhang and so the wall doesn't get near as much water
in a rainstorm. So I didn't catch the problem until the second wall.

I'm sure you're right about most people just not knowing the problem
they're creating. The 8' horizontal joints on my house are all 0" gap
between flashing and siding, and the siding is buckled out in some
places as a result.

stained b/4 they are put up. I have to "LOL" at myself, I tried it to stain
the entire panel b/4 putting them up. I found out you never let the sun hit
the panel b/4 it goes up, while still wet. I found out the panels take a
banana shape, only worse. 8-)

Cabot, it's nice to hear that even you have some LOL moments like
that. Your work looks fabulous.