Hardie Plank Lap Siding and Vinyl window flashing

[Scott C Simpson]

Should a home built in 2004 with HardiePlank lap siding and vinyl windows have Z flashing, no caulk at the top of the windows, and a gap as in the picture provided? I am looking at a home which has no gap, and the windows are caulked. The house has no overhang, so I am concerned about water intrusion.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33645&stc=1

[Gunnar Alquist]

Should a home built in 2004 with HardiePlank lap siding and vinyl windows have Z flashing, no caulk at the top of the windows, and a gap as in the picture provided? I am looking at a home which has no gap, and the windows are caulked. The house has no overhang, so I am concerned about water intrusion.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33645&stc=1

Hi Scott,

Is that from the manufacturer's instructions? If so, they are the authority on proper installation of their product. What is detailed should be executed.

[Scott C Simpson]

Hi Scott,

Is that from the manufacturer's instructions? If so, they are the authority on proper installation of their product. What is detailed should be executed.

The image is not from the 2004 installation guide. I asked Hardie and they said they always have recommended Z flashing but I cannot find documentation (it doesn't mention flashing windows in the 2004 guide).

The house I am considering purchasing has HardiePlank lap siding, vinyl windows with no flashing visible and the windows caulked. The inspector told me it was normal for the time period and the windows were probably flashed beneath the plank via flashing tape.

The house has no overhang and a flat roof — so, I am concerned about water intrusion, although there is no obvious evidence.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33646&stc=1

[Jerry Peck]

From 2001 and then 2005 (which I had to break down page by page as the file was too large to upload as a complete document, identified as (pg1, pg2, pg3, and pg4).

[John Kogel]

There will be nothing but trouble there. It doesn't really matter about the code violation, unless you need documentation to get out of a contract. The builder is not coming back to fix it.

The flashing can be metal or vinyl. We use metal, usually painted Al.

A house in Oregon with no roof overhang is a house with wet walls. It must be a nice location for you to even consider it.

[Jerry Peck]

There will be nothing but trouble there. It doesn't really matter about the code violation, unless you need documentation to get out of a contract. The builder is not coming back to fix it.

The flashing can be metal or vinyl. We use metal, usually painted Al.

A house in Oregon with no roof overhang is a house with wet walls. It must be a nice location for you to even consider it.

Years ago I used to receive calls and emails from people in Oregon about Hardiplank installed over no felt and no WRB, see that little asterisk by WRB?

At the time, the Oregon code cited 'per manufacturer's instructions' and the manufacturer's instructions referenced those codes.

My recollection is that the Oregon codes were not one of those codes, and because the Oregon codes did not call for a WRB, the builders were "not required to exceed minimum code requirements" - from talking to various building officials (defending a weak code) and various attorneys (about chances of winning) in Oregon.

Let the contractors control the code process or the legislators and you get a weak code.

We are always going through that problem (legislators and contractors) in Florida, even this year - maybe Hurricane Irma will knock some sense into the legislators as to why codes are needed.

Same applies to Houston and flood elevations.

And the current President who used an executive order to reduce FEMA flood elevations. Just an example of interference into codes by those who don't know squat about the reasons for having codes.

[Scott C Simpson]

There will be nothing but trouble there. It doesn't really matter about the code violation, unless you need documentation to get out of a contract. The builder is not coming back to fix it.

The flashing can be metal or vinyl. We use metal, usually painted Al.

A house in Oregon with no roof overhang is a house with wet walls. It must be a nice location for you to even consider it.
I am not concerned about code violation, I am only concerned about water getting inside the walls. I see or smell no evidence of it inside. However, there is a lot of backsplash on the north wall and areas where the gutters have overflowed due to the flat roof not being cleaned. Also a bit of algae on this same wall.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33652&stc=1http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33653&stc=1

[Jerry Peck]

Scott,

There may be only two ways to know how your siding was installed: a) find a butt joint which is not tight and not caulked, use a bright concentrated beam flashlight to look into the open space and see what is there (if you can see in that space); b) remove a piece of siding.

Doing a) might let you see what is behind "the butt joint", but it will not tell you what is behind the other parts of the siding - only doing b) will tell you how much you have to be concerned.

[ROBERT YOUNG]

Morning Scot.
I refer to top window flashing as the Drip Cap. Z flashing is also used.

I rarely if ever see Drip Cap/ Z flashing on basement windows. The proximity to the foundation is likely the reason why. In other words, water will not enter the wall assembly. The space between the siding and foundation is essentially a drip screed allow water to drip to the soil.
Note: If the basement window was not installed correctly, and that includes flashed, the chances of water intrusion dramatically escalate.

That being said. You appear to have below soil roof water dispersal. I would terminate roof water being distributed below the soil and install downspout extensions and cap the below grade pipes.

[Jerry Peck]

In other words, water will not enter the wall assembly. The space between the siding and foundation is essentially a drip screed allow water to drip to the soil.

Only with proper construction methods, and a proper WRB is number one on the list, and that is what many homes in Oregon were built without.

[ROBERT YOUNG]

Along with, identifying the WRB, type and permeability, and everything the OP hope to obtain, the siding components, comes destructive means, and as stated, identification.

As well, during the assessment, only a small portion of the entire siding assembly is identified as correctly or incorrectly installed.

I am sure an interior/exterior infrared survey would be able to reasonably conclude if weather has a chance of entering the envelope.
A moisture meter would determine if moisture was present and the amount Mc per material.

[ROBERT YOUNG]

Scot, if there is a space wide enough between the siding and foundation you should be able to see a building wrap, moisture barrier, Water Resistive Barrier, or WRB.

You will likely require (2) persons/people to do this on your own seeing it will be your first attempt at viewing the interior of the siding assembly.

I use several methods and have various tools to get the job done successfully. I do not do destructive analyses.
Sorry I forgot to bring up the method earlier. Ops.:o

1: You require a good flashlight, a mirror, large enough to suite your needs. The siding requires good flashing, ha ha ha.
Shine the light up the assembly from the ground and use the image in the mirror to identify the color and texture of the material.

2: Use a HD camera with a flash. Point the lens up the cavity and take several images.

3: Boar scope.
A HD boar scope will get good images if there is enough room for the head of the lens.

Bring any information back to the MB. That includes images.
Good luck.

[John Kogel]

Scot, if there is a space wide enough between the siding and foundation you should be able to see a building wrap, moisture barrier, Water Resistive Barrier, or WRB.

You will likely require (2) persons/people to do this on your own .Scott said he had an inspector, who thinks the windows are flashed with tape. The inspector should go check for WRB, IMO.
Hopefully, the inspector carries a moisture meter for checking the window sills. But Scott is asking here, so we have to wonder, what about your inspection report?.

Also, Robert, you mention the downspouts. When we see PVC pipe here, house less than 30 years old, it means the roof drainage is solid PVC pipe to a storm drain , French drain system, or out to daylight if there's a slope or ditch. So that is much better than downspout extensions. I would again clarify this with the inspector.

Scott, if you are set on the flat roofed house in Oregon, you are correct that the roof drains need constant cleaning, several times a year, and that a flat roof often holds large puddles of water all winter long, which leads to sagging roof joists and lthen deeper puddles. The roof pics may show watermarks where the puddles will form once it starts raining again.

You are buying a headache, but there are ways to fix that. See if the zoning will allow you to build a proper sloped roof with proper overhangs.

[ROBERT YOUNG]

Scott said he had an inspector, who thinks the windows are flashed with tape. The inspector should go check for WRB, IMO.
Hopefully, the inspector carries a moisture meter for checking the window sills. But Scott is asking here, so we have to wonder, what about your inspection report?.

Been doing weather intrusion assessments repairs upwards of +25 years.
A sign of the existence of something, moisture or conditions that can become problematic, especially of an undesirable situation, is telltale with bulk water.
Window sills are not the best place to hypothesize the lack of WRB or poorly flashed basement windows.
If the window was not properly installed, diagonal or horizontal rain will surely leave tell tale signs.;)

I have 3 moisture meters, (2) brand name, in my bag. 1: TRAMEX MRH III. 2: DelMhorst TechCheck Pro with 6.6" probes.

To attribute water, and gravity's effect on bulk water, it is short sighted to stop at the window sills, or count out condensate, which leads me to ask, what about your inspection report?

Mine have, or have no adverse conditions in drywall BUT, it depends upon conditions and symptoms as you and the rest hear well know.
If a window sill is suspect, or red flag, 5 will get you 10, at least, there is water vapor or bulk water in the wall assembly. Time, temperature and gravity will do the rest, to insure adverse conditions will exist eventually.


Also, Robert, you mention the downspouts. When we see PVC pipe here, house less than 30 years old, it means the roof drainage is solid PVC pipe to a storm drain , French drain system, or out to daylight if there's a slope or ditch. So that is much better than downspout extensions. I would again clarify this with the inspector.
Roof water dispersal directed to the perimeter drainage field, & "french drain", that 4" pipe enveloped in ><2' of aggregate, have been banned since 1958 in Canada's building code.

Below soil roof water dispersal, of any nature, is needless, and a disservice to the homeowner.
Yes at times dry wells are necessary but they should be built by someone knowledgeable of the soil in that area.

Partial Blockage, pipe breaks, pipe damage, uncoupled pipe fittings go undetected.
The shear volume of water can set up needless hydrostatic pressure in a specific area as well as change the soil density, soil composition and sinkholes appear.
Once water creates a path of least resistance, a path remains there. It will not diminish as long as water can be directed to it.

IMO, money spent below the soil to repair costly foundation or water control damage is wasted money. It starts above the soil when you own the home. Insure the lot slopes away from the home. Take care of the lot.

[Scott C Simpson]

I don't think the inspector checked for a WRB, or did moisture checks. There is a small amount of suspected fungal growth on the attic sheathing. I have a mold inspector coming out this week to take a deep look at that issue.
At that time I will check on the WRB. I have a borescope (which should fit under the planks), I have a moisture meter (pinless, and pin), as well as an infrared camera.
It has hardly rained in 6 months in Oregon though.

As far as those downspouts, I do believe they are connection to the city wastewater system.

Any suggestions on the best way to use the tools I have are appreciated.

[John Kogel]

Hello Scott. Using a small mirror as Robert described, you may be able to see WRB under the bottom plank.
You will not detect much moisture now, since it has been dry for months. Gently probe the drywall and baseboard areas, check for soft spots or paint blisters.

Check the roof for water marks from ponding.

[John Kogel]

Here's another idea.
If you are inside and see a cable outlet on an exterior wall, and have time, pull the screws and see what is behind the cover plate. There is often no outlet box, just a bracket and a big square hole. Then you can pull insulation aside and see the sheathing. On a cheap flat-top house built after 1985, it will be OSB sheathing. See if there is a water stain at the base where it nails to the sill plate.
A bathroom toilet roll holder that is built into the wall comes out with 2 screws, big hole in the wall there.

Small hole, use your boroscope, save pictures to examine on a PC. Good luck.

[ROBERT YOUNG]

Morning John.
By inspecting a localized area gives a localized result. It restricts the observation to a particular place.
A mirror around the perimeter of the siding starter course will at least allow a generalized result of that area.

I attached an image from Hardie Boy for recommended installation practices.
Click on the image to view the entire video.
I never installed Hardie Board siding but I did install metal and vinyl siding. My first siding job I hired an unemployed professional siding installer. He worked with my company about 3 months and then moved on. Labour in Construction transit. They come and go.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33663&stc=1 (https://www.youtube.com/watch?v=2ksJOQKd_aU)

Morning, Scott.
1: Borescope.
Use you borescope at gaps between starter board. Starter Butts should not be tight. That gap is a drip screed. Corners work as well.

You should see WRB for 2" or more, dependant upon the intersection, below the start strip, though some installer cut back the WRB flush or nail the start strip just above the WRB to hide the material.

2: Moisture meter.

May I recommend: Do a thorough visual grid/graph assessment.
Drywall that's been compromised by water can appear to be discolored, or show signs of deterioration. Drywall top sheet can blister, wrinkle like old skin. Come to think of Scott, I can show you some on my body right now, ha ha ha.
Not to much for the time being but you can not escape time and gravity.:mad:
Paint will show heus, or color appearance parameters.
Wallpaper delaminates, seams peel.
NOTE: Color is typically the first sign.

Purchase Graphpad at your local office supply store, or make one with a pencil and writing pad.
Each square = one (1) square foot.
10' by 12' surface = 120 vertical/horizontal square feet.
Every sq foot of that assigned area measure the MC/MD and place the readings on the grid in it's allocate space.

a. Start with average MC readings in the middle of the home on an interior wall.
I measure MC on at least 2 interior walls.

b. Move onto the exterior wall at the window in question, or anywhere you wish.
Take average MC readings every sq ft of that assigned area and place the readings on the grid in it's allocate space.

Scott. Read how the Moisture Meter works, what to avoid, and what the readings mean in real time...

Get back to us with your results.

[John Kogel]

That picture and video is informative for older installations, such as Scott's house.
Localized views are all he is going to get, no?.

As you know, the way we expect to see new Hardie installed is on rain screen, either vertical wood strips or 'DryWall' mesh, with a bug screen, perforated 3/8" channel strips, around the base.

At the butt joint, best to use a strip of Al flashing secured at the top with a nail. Where planks butt to trim planks are caulked. That's what the muni inspector will look for in new construction, as well as the head flashings over windows, doors, and band boards.

[Scott C Simpson]

Here is what I found yesterday:
Beneath the bottom plank via borescope:
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33664&stc=1http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33665&stc=1
Is the red lettering a moisture barrier?

Concern 1:
While in the attic, it was possible to see daylight through one spot where the OSB joined. This was near the roofline. I assume there is no WRB there?
Concern 2:
There is a moisture issue in the attic which has led to a minor mold issue in the attic, the below picture is from drips on the attic sheathing onto the insulation. This is widespread in the attic. The assumption is this is caused by condensation.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33666&stc=1
Concern 3:
Bottom furring strip under siding completely rotten in the spot with the broken siding. Also, hairline crack in slap at same location. Also, evidence of water trying to get out, or in, on inside window sill in this same location. This is the same wall where light shines through in the attic near the roof line.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33667&stc=1http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33668&stc=1
Concern 4:
There is a horizontal furring strip around the bottom of the siding with no detectable gaps. On a different wall than above, there appears to be some rot and fungal growth.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33669&stc=1

Please give me your thoughts! I really appreciate your expertise.

[John Kogel]

Yes, the material with red lettering is Tyvek weather barrier, good.

The only way the furring strip would rot is from water cascading down the wall behind the siding. Whether the water is running over the Tyvek or under is not known. I assume the last picture of the furring strip is looking up from below. Rotten wood is attractive to carpenter ants, boring beetles and dampwood termites. Once in there, they will move farther in.

Don't worry about the minor shrinkage crack in the concrete.

Where you saw light, it is normal to have ventilation of the attic space at the eaves, so we expect to see daylight at that junction on a well-built house. But this house has no eaves, so I suppose there is an unintended gap between the roof and the wall.

Excess condensation indicates a lack of attic ventilation, bad. As I said from the beginning, nothing but trouble there.

Moist air from people living, cooking and breathing leaks past the ceiling thru gaps, light fixtures
and an attic hatch poorly sealed. A ventilated attic space is essential to allow that moisture to escape. Even a flat roof (should be low-slope) should have ventilation of the rafter cavities.

That interior window sill is just the visible part of the problem. There is hidden damage to the structure there. I don't know why you are still looking at that place but it is a sick structure that wasn't built for the West Coast climate.

[Scott C Simpson]

I don't know why you are still looking at that place but it is a sick structure that wasn't built for the West Coast climate. I really love the layout: http://riverdistrictstudio.com/house/img/04.jpg

[John Kogel]

Nice 'polished turd'. That wall is melting. ;)

It can be fixed with what I said, have a truss designer build you a proper roof, and then get a qualified builder to install those trusses over that cracker jack design.

Building that way is cheap, and standard in commercial buildings, but those buildings have concrete block walls. They also have ventilated rafter cavities or they should.

You need to elevate the roof surface so that there is a large air space above the ceilings. That space is ventilated with a continuous ridge vent on the high sides, and the lower eaves are open, covered with perforated Al covers.

If a designer doesn't like the look of overhangs, then he should have the walls done in cast-in-place concrete, such as the foam block systems. The walls then need a metal cap flashing with a drip edge.

[Scott C Simpson]

http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33670&stc=1

You need to elevate the roof surface so that there is a large air space above the ceilings. That space is ventilated with a continuous ridge vent on the high sides, and the lower eaves are open, covered with perforated Al covers.

The attic is around 4 feet tall. Maybe more or less depending on the ceiling height in the room below.

[ROBERT YOUNG]

No buildings with that roof/attic architecture in my neck of the woods that I am aware of.

May require retrofitting the venting methods.
Condensate is one issue.

Mechanical venting may help and will eliminate some of the side vent registers.

[Scott C Simpson]

Also, the header on the garage is sagging. How much of an issue is this?
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33673&stc=1
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33672&stc=1

[John Kogel]

Hold the edge of a sheet of paper to the picture of that header to get a rough idea of its droop.

I would check the roof joists above the garage. There better not be any sag there in the roof. Then if it is just the door frame, it may be fine like that, stopped sagging, or it may drop further, then it is a two day job all goes well to replace it with a laminated beam maybe.

I know I have been pessimistic all along, but I hate to see houses go downhill from lack of a proper design. The issue with that place will always be the roof. You have an abundance of deciduous and needle-casting trees in close, so that roof will be constantly needing clearing of roof drains. Four times a year, you need to get up there and clear the drains.

The debris can be blown off with a leaf blower, and try to catch it on a tarp on the ground.
A steep pitched roof sheds that debris for the most part and then you can install gutter guards.

[Jerry Peck]

Could be an optical illusion as I am looking on my phone, but I don't see the garage door header sagging; I see that beam which runs from column to column to column sagging.

[Jerry Peck]

Okay, power back on and viewing on my computer again.

The attached drawing confirms (as best possible on a photo) that the beam is sagging and the garage door header is straight.

[Scott C Simpson]

Okay, power back on and viewing on my computer again.

The attached drawing confirms (as best possible on a photo) that the beam is sagging and the garage door header is straight.
It's hard to tell from the photos for sure. Here is a zoomed image.
http://www.inspectionnews.net/home_inspection/attachment.php?attachmentid=33677&stc=1

[ROBERT YOUNG]

Might be the siding installation Jerry.
I see no deflection in the garage door opening.

[John Kogel]

Scott saw it and it is there. Hold a straight edge to a flat screen monitor. Over an inch of sag at the door frame. Yes, sometimes a camera lens distorts the pic, so best to measure or shoot a laser beam across the opening.

[Jerry Peck]

Might be the siding installation Jerry.
I see no deflection in the garage door opening.

That is what I am saying.

It is the beam out in front of the house which is sagging, not the garage door header.

- - - Updated - - -


Scott saw it and it is there. Hold a straight edge to a flat screen monitor. Over an inch of sag at the door frame. Yes, sometimes a camera lens distorts the pic, so best to measure or shoot a laser beam across the opening.

John,

You are looking at the beam which is on the columns out in front of the house, the house and the garage door is back behind that beam.

[John Kogel]

No, I was and still am seeing sag in the garage door opening, not the arch or whatever that structure is. The seams in the door are straight, the 2X8? above the door has a droop in it.
Those double garage doors are often weak in that area, no? It's not surprising at any rate, and there are carpenters everywhere that have repaired those, or concealed them behind trim.

I've got a picture of one of those door frames encased with river rock style faux stone, defying gravity. Where do they get these ideas? ;)

[Gunnar Alquist]

I have exhumed this outdated thread (rather than start a new one) to verify my observations and thoughts.

California Residential Code 703.4.4 requires head flashing over exterior trim:


R703.4 Flashing. Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Self-adhered membranes used as flashing shall comply with AAMA 711. Fluid-applied membranes used as flashing in exterior walls shall comply with AAMA 714. The flashing shall extend to the surface of the exterior wall finish. Approved corrosion-resistant flashings shall be installed at the following locations:
4. Continuously above all projecting wood trim.


Now my question:


I recently inspected a new home which had galvanized steel head flashing over the window trim at the sections of the exterior that are lap sided. However, there is no head flashing over any of the trim at those areas that have the large sheets of Hardie Panel. The lead carpenter informed me that there is no practical way to install the flashing over the trim where panel siding is present without installing the trim first and cutting the siding around the trim, leaving it inset by the thickness of the siding (this is done with lap siding, but generally not panel or board & batten around here).


This lack of head flashing is evidently allowed by the AHJ, since I see it on all similar homes in my area (I haven't actually verified this with the building department yet). While I see LC's point, as far as I know, it does not meet manufacturer's installation instructions or the current code requirements.


One item of note. This is California and the earth tends to not stay in one place for very long. In the past, T1-11 siding was used as a part of the seismic resistance of the home; however, I suspect that it is no longer approved for that function. I see OSB or plywood (less commonly) used for the seismic diaphragm.


Any thoughts?
What do you do in cases like this?
Does anyone know of any other way to provide head flashing without insetting the trim?

[Jerry Peck]

It's all about the wording in the code ... and presuming that the contractor did otherwise correctly.

Bold red in the code reference is mine.


I have exhumed this outdated thread (rather than start a new one) to verify my observations and thoughts.

California Residential Code 703.4.4 requires head flashing over exterior trim:


R703.4 Flashing. Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Self-adhered membranes used as flashing shall comply with AAMA 711. Fluid-applied membranes used as flashing in exterior walls shall comply with AAMA 714. The flashing shall extend to the surface of the exterior wall finish. Approved corrosion-resistant flashings shall be installed at the following locations:
4. Continuously above all projecting wood trim.

.
.

The lead carpenter informed me that there is no practical way to install the flashing over the trim where panel siding is present without installing the trim first and cutting the siding around the trim, leaving it inset by the thickness of the siding (this is done with lap siding, but generally not panel or board & batten around here).


This lack of head flashing is evidently allowed by the AHJ, since I see it on all similar homes in my area (I haven't actually verified this with the building department yet). While I see LC's point, as far as I know, it does not meet manufacturer's installation instructions or the current code requirements.

The lead carpenter is correct, and if they did the Hardie Panel install correctly, then there may not be a problem ... correctly ... is a very big presumption to make.

Install the window, properly flash it in place, then install the Hardie Panel over the flange and flash it in place.

Or

Install the Hardie Panel and flash it to the window opening, then install the window and flash it to the Hardie Panel.

Each being done "correctly", with care, and with the proper materials, following the manufacturer's installation instructions, should lead to a weather-resistant install.

The Hardie Panel (Hardie Plank) trim, not being wood (I am presuming that the trim is Hardie Plank trim (or maybe Hardie has a Hardie Panel trim of common widths?), as both the Hardie Panel and Hardie Plank trim is resistant to rot, unlike wood, and ... if all is done properly and in accordance with the installation instructions ... I can see it working correctly.

I'm looking at this from a logical water-shedding point of view combine with Hardie Plank and Hardie Panel are resistant to rot and decay (if either the siding panel or trim was wood ... all bets are off and a flashing is required).

Note: I haven't looked at Hardie Plank/Panel installation instructions for several years - what does it say?

What does the window manufacturer say for flashing the window?

[Gunnar Alquist]

Hi Jerry,

The Hardie Panel instructions has z-bar flashing over horizontal trim. I believe it is wood trim on this home, but I will go back out tomorrow morning to verify.

Yes, presuming the windows and doors are correctly flashed, they are not likely to leak. My understanding is that the z-bar flashing is to protect the wood trim from moisture damage.

I was unable to copy/paste directly from the Hardie instructions, but this image is similar.

[Jerry Peck]

My understanding is that the z-bar flashing is to protect the wood trim from moisture damage.

Gunnar,

That is correct, but the see flashing not only protects the wood trim from water rotting the top of the wood trim, it also keeps water from getting between the wood trim and wood siding behind the wood trim.

Water between the wood siding and trim not only rots the wood trim, it also rots the wood siding, and rotted wood siding let's water get behind the siding - if no WRB, any not properly flashed areas, defects in the WRB and/or flashing (nails, cuts, tears through WRB or flashing) and now there is water in the wall cavity. Especially for areas that don't use plywood or OSB sheathing behind the siding (cladding). Of course, though, the sheathing just delays the water getting into the wall cavity, but when the sheathing rots ... there is even more to repair.

Did you notice in your photo that when they spray painted the wall, the angle of the gun allowed the paint to "miss" the top of the trim? Quickie spray job with no back rolling and no cutting in with a brush.

[Jerry Peck]

https://www.jameshardiepros.com/getattachment/2510b556-ee39-416d-8ef7-198c698f4cc7/hardiepanel-single-family-hz10-us-en.pdf

See the General Requirements image, and Figure 4 image (I also included a "joint" image, but that is not a "joint").

That shows that your photo is not in accordance with published manufacturer's installation instructions ... provided that the instructions I linked to are applicable to that installation as there have been some changes over the years and for different areas of the US. The Z10 logo shows the area of the US that the Z10 instructions apply to and includes California - Hardie has other instructions for other zones.

[Gunnar Alquist]

Gunnar,

That is correct, but the see flashing not only protects the wood trim from water rotting the top of the wood trim, it also keeps water from getting between the wood trim and wood siding behind the wood trim. Water between the wood siding and trim not only rots the wood trim, it also rots the wood siding, and rotted wood siding let's water get behind the siding - if no WRB, any not properly flashed areas, defects in the WRB and/or flashing (nails, cuts, tears through WRB or flashing) and now there is water in the wall cavity. Especially for areas that don't use plywood or OSB sheathing behind the siding (cladding). Of course, though, the sheathing just delays the water getting into the wall cavity, but when the sheathing rots ... there is even more to repair.

Jerry,

Well... I would argue that Hardie Panel is not "wood siding", but keeping the water out of the space between the trim and siding is the point of the z-bar.

While I cannot say for sure that all homes have a WRB under the siding, I have yet to see one that does not (referring to newer homes. Older homes are a different story). And, I would guess (again, cannot say for absolute sure) that there is 1/2" struct-one under the siding. Pretty much standard here in earthquake country.



Did you notice in your photo that when they spray painted the wall, the angle of the gun allowed the paint to "miss" the top of the trim? Quickie spray job with no back rolling and no cutting in with a brush.

I did indeed.


https://www.jameshardiepros.com/getattachment/2510b556-ee39-416d-8ef7-198c698f4cc7/hardiepanel-single-family-hz10-us-en.pdf

See the General Requirements image, and Figure 4 image (I also included a "joint" image, but that is not a "joint").

I was unable to pull Figure 4 out of Hardie's installation instructions, which is why I posted the one that I did. Granted, the one I posted does not show trim, but the intent is similar. Keep the water on the exterior.

[Jerry Peck]

Jerry,

Well... I would argue that Hardie Panel is not "wood siding", but keeping the water out of the space between the trim and siding is the point of the z-bar.

I agree. What I was saying was that Hardie Board material is no where as susceptible to damage from water as wood, therefore such installation would likely not create a problem if ... that big IF ... if all behind it was properly flashed.


I was unable to pull Figure 4 out of Hardie's installation instructions,

I used that 'print screen' magic I referred to on another post. :cool:

[Gunnar Alquist]

I went back out and the trim is indeed wood. So, the primary issue would be protection of the wood trim (as long as the flashing and WRB is properly installed behind the siding).

In addition, the only trim that really would be subject to rain would be on the tall walls. Those windows that are under roof overhangs should be protected from rain unless the wind is really strong.

[Jerry Peck]

I went back out and the trim is indeed wood. So, the primary issue would be ...

... would be not installed in accordance with the manufacturer's installation instructions. Wood trim (required by code - specifically- and manufacturer's installation instructions) and Hardie Board material (required by code - by reference to, and by the, manufacturer's installation instructions).

[Mark Parlee]

Getting here a little late.
Hardie requires a flashing at the horizontal edge of their material as well. This is not a requirement just for wood trim.
Attached are the details.345833458434585