View Full Version : Wrong window for siding?

Vern Heiler
10-02-2008, 05:20 PM
New construction Hardie Board siding and vinyl windows. The windows are: MI Windows & Doors Model # 4300.

None of the windows are sealed at the siding. The windows are flanged type "self flashing" if you believe in that, and have what the manufacture calls (intergral "J" channel).

I see this type of window with vinyl siding all the time, never caulked at the edges to the siding. The manufactures installation instructions for there vinyl windows has this:


Is the 4300 window designed for vinyl siding only? Can they be used with cement board siding? I don't see how you can seal at the edges with the intergral "J" channel in the way. There is no visible flashing or drip cap at the top of the windows either. Water will go behind the siding, leaving the house wrap and flashing as the only barrier to the sheathing and studs.

Do I recommend installing a drip cap or flashing at the head and sealing at the side jambs, or state "wrong window for the siding"?

Any help is appriciated.


wayne soper
10-02-2008, 08:48 PM
The J channel is a slot that the siding slides into. Designed to make the siding application easy and leakproof.The back side of it is much wider than the outside and should be taped to the house wrap.
Any water entering in that gap you are worried about will drain down along the edge the same as it would with vinyl siding so I don't see it as a problem. Unless the manufacturer of that window specifically says it is only to be used with vinyl siding. Or unless it's not taped like 99% of the applications out there.

Vern Heiler
10-02-2008, 09:09 PM
Thanks Wayne, I don't know if it is flashed to the house wrap or not, don't eaven know if there is house wrap? I'm sure there is, nice 3,000 sf. house! The problem I have is where the manufacture says to leave a 1/4" gap to be caulked, except for vinyl J channel. Do they mean the vinyl J channel on there window or vinyl J channel of the siding?

Brandon Whitmore
10-02-2008, 09:20 PM
I'm not gonna look up the manufacturers installation instructions, but I think that installation is crap.
On vinyl siding installations it is typically recommended to run the bottom strip of flashing back to the exterior of the siding right beneath the window so water does not travel all the way down the wall-- did they do that here? Also, vinyl siding breathes pretty well. How often are housewrap/ flashing installations done right? I just think that installation is asking for it.

wayne soper
10-03-2008, 04:43 AM
heres the window
heres the instructions

Jerry Peck
10-03-2008, 08:41 AM

Based on the installation instructions (than you, Wayne) the window looks to be installed as it was designed to be.

Granted, you cannot see how it was flashed to the wall or WRB, if at all, but, can you see that on other windows after the siding has been installed? Nope. So I would treat that as I would any and all other window installations where you cannot see it before the siding is installed.

Brandon Whitmore
10-03-2008, 10:16 AM
Those instructions don't say you can't do what was done, but they are pretty generic installation instructions for all of their windows.

That kind of window is gonna channel quite a bit of water behind the siding, and I don't like it either way......... It's just asking for problems.

I put in an e- mail to their company because I am now curious. I'll post their reply

wayne soper
10-03-2008, 01:42 PM
OH, you mean like a normal window:D

Billy Stephens
10-03-2008, 02:29 PM
OH, you mean like a normal window:D

Brandon Whitmore
10-03-2008, 05:59 PM
OH, you mean like a normal window:D

The new design of windows are problematic, but at least there is usually a spot where you can caulk the frame to the siding to limit the amount of moisture that channels to the typically improperly installed WRB and flashing. (run- on sentence huh)

This design just makes things worse is all. It's not like the manufacturer of the window will stand behind the installer of the window, flashing, and WRB-- they just make the windows and tell everyone to keep the water out somehow........ but it's not their fault if water gets in........

Mike Schulz
10-14-2008, 10:47 AM
I have been fighting this with the builders and manufacture window rep for years. I call out everyone. The rep is going to speak with the large builders and explain to them that they don't care if there is siding on the house or not. They only care about the installation of the window in the wall. They say follow siding installation instructions. I can't find anything in siding instructions on this particular question. The rep was suppose to get back with me when he spoke with the builders in question but I haven't heard from him in a month.
Anyone interested call Tim at 717-365-3300 ext. 2512 and let us know (MI windows and doors). Maybe if enough of us complain we can get this changed. Until then I will keep calling it out and fight with the builders. Reason this is on going one of the builders was pissed at me because I call it out on his stuff for 3 years and he is sending a complaint to the licenses board.

My beef is the siding is notched up under the integral "J" of the window and if it is a second storey window it has to run all the way to the foundation to exit.

Jay Ray
10-30-2008, 01:50 AM
Ask for pictures of the home while it was under construction. Most homeowners document the building process for their scrapbook.

I would like to see images of any window or door before the siding was installed. Most likely they did not tape the nail flange as it IS NOT part of the flashing package! If they did tape the flanges, is the tape applied to the house wrap?

The window design is perfect as long as it is an intragrated nail flange. It is the contractors lack of training and the instalation method that is the issue.

You do not seal the siding to the PVC "J" channel. This traps moisture. If the window is flashed properly you want water to flow out ASAP and air to circulate around the window to dry it. The flashing and house wrap give you a surface for the drain plane. Simple rule: the faster water flows in and out along with the higher the air circulation causes less issue. (If flashed correctly of course)

Hardy board is pre-punched. The nails fit loose in the punched holes. The nail penatrated the house wrap thus voiding the air/water barrier. Water follows the nails into the sheathing. I will almost always see 1" round rot spots where the siding nails attach to the sheathing after 5-7 years.

OSB in the Northeast is proving trecherous to this phenomenon!

Jay Ray
10-30-2008, 02:33 AM
Let me give you the truth about PVC products and the USA.

PVC windows were invented in Europe after WW2. No natural resourses after the bombings. The Germans made many mistakes and learned from them.

PVC products hit Canada in the 60's. They made the same mistakes the Germans made in the 40's.

PVC then came to America in the 80's. We are STILL making some of the same mistakes both Canada and Germany made years ago!

I went to a window training school in Canada years ago and got this info directly from the CEO of a major PVC extruder.

"We Americans are proud and want to do it on our own" he stated. We refuse to learn by other countries...it's just they way we are. I can give several examples but don't have time. Instead I will give one we never think about.

Sunlight....ie, UV rays hardens the PVc and you all remeber how bad it faded and cracked in the not too distant past. Germany had this issue in the mid 40's and solved it by adding a UV inhibitor. Canada had the exact issue in the 60's. American PVC products have been adding UV emolents only in recent history. Refering to PVC siding and PVC window products.

I don't want to pick apart the window instalation guide sent but will tell you from experience it has a major flaw. The #1 issue with sealing PVC to any substrate is expansion/contraction. (I attended a Dow Corning class some time back). Why on earth would you rely on sealant behind a pvc nail flange to a wood sheathing product? It's not going to last and experience shows us it is hit and miss. Also Germany and Canada learned about Micro-Cracks. You are told to hold the nail off PVC siding by 3/16" for movement. What happens when you nail a window flange tight. Driving home the nail causes tiny cracks in the nail flange. When the temperature changes the PVC cracks. Some cracks lead into the frame of the window. This bypasses the sealant behind the nail flange. This is why Vicor and Grace makes self penatrant tapes. It covers these simple issues found many years ago.

For any contractor as well as anyone in the building trades I would refer you to Jeld-Wen's site. I go to many window and door manufacturues schools (as many as 4 times a year in 2 countries) to learn the LATEST in window/door installation methods. J-W has the most comprehensive installtion method I have ever studied. They happened to put their method together after buying a Canadian window co. a few years ago.

Jerry Peck
10-30-2008, 05:40 AM

Excellent information on that Jeld-Wen site.

Includes a "drain mat" which I have not seen before, looks like it provides an angled, slope-to-outside, draining surface.

Also noticed this in the installation instructions: (underlining and bold are mine)

- - 1. Install exterior wall surface within seven days of window installation.
- - 2. Maintain gap of 1/4"-3/8" between window frame and final exterior wall surface (siding, stucco, etc.).
- - 3. Seal the gap with backer rod and sealant. Do not apply sealant on top of window frame or drip cap if present.
- - 4. On the interior, seal the void between the rough opening and the window frame with backer rod and sealant, or with low expansion foam. Do not use high-expansion foam as this may cause frame deflection.
- - 5. Adjust window for best operation.
- - 6. Protect recently installed units from damage from plaster, paint, etc. by covering the unit with plastic.
- Note! For integral J-channel vinyl product installed into a structure with shiplap siding, no expansion/contraction joint is needed.

Brian Robertson
11-02-2008, 04:25 PM
So now I am curious, does this window need to be written up?

Mike Schulz
11-02-2008, 05:01 PM
You do not seal the siding to the PVC "J" channel. This traps moisture. If the window is flashed properly you want water to flow out ASAP and air to circulate around the window to dry it. The flashing and house wrap give you a surface for the drain plane. Simple rule: the faster water flows in and out along with the higher the air circulation causes less issue. (If flashed correctly of course)


If you don't seal around the window because of what you described why caulk anything on the exterior. Siding butt joints, siding to corner trim boards, etc.

If the window is flashed properly you want water to flow out ASAP and air to circulate around the window to dry it.

If the window was caulked there would be limited amount of water that would get behind it. Also the siding is only caulked to the frame and if water needs to get out it can exit out the bottom of the panels that are lapped. The overlapped panels are open for breathing. and if water does get behind it it will still have the same drain plane. The siding gets caulked on the surface to the inner part of the fin. The back of the siding is still open to the wall for drain purposes as you described. I am not understanding why caulking would trap water. The caulking just limits the amount. If water gets in the top channel of the window it will run down the sides and behind the notched siding that is installed under it. Then it needs to find a exit point whether at the foundation, nails in the wall, through the wrap (vapor) or any other exit point.

M/I has a window that is exactly the same. One with and one without the "integral" channel. The one with out the channel gets caulked and according to the builders the ones with a channel does not. Now why caulk one and not the other. The one without the channel gets caulked so would that not trap water as you described?

Just trying to get to a reasonable conclusion so I can explain it to my customers.

Jerry Peck
11-02-2008, 05:12 PM
M/I has a window that is exactly the same. One with and one without the "integral" channel. The one with out the channel gets caulked and according to the builders the ones with a channel does not. Now why caulk one and not the other.


The one without the integral "J" channel gets a "J" channel installed adjacent to the window and into which the vinyl siding goes.

Does vinyl siding get caulked into each and every "J" channel?

Do the "J" channels get caulked to the sides of the adjacent windows?

Mike Schulz
11-02-2008, 05:27 PM

The windows with out the channels around here most of the time is with cement fiber. The ones that do get Vinyl "J" channels are caulked to the frame. Also with or without the "integral channels the vinyl siding gets flashing in the bottom corners and overlaps the adjacent panel below it, nailing strip to direct water to the weep holes in the bottom of the panel.

Lets stick to cement fiber, that is the question about caulking.

Ted Menelly
11-02-2008, 05:28 PM
Not much of any kind of lip at all on the sides of those windows. Can't caulk the vinyl siding for spacing for expansion and contraction.

New window time.

Jerry Peck
11-02-2008, 05:40 PM
The windows with out the channels around here most of the time is with cement fiber. The ones that do get Vinyl "J" channels are caulked to the frame. Also with or without the "integral channels the vinyl siding gets flashing in the bottom corners and overlaps the adjacent panel below it, nailing strip to direct water to the weep holes in the bottom of the panel.

Lets stick to cement fiber, that is the question about caulking.

You can't stick to fiber cement, the question was about the window with the integral "J" channel ... so you must stick to *that type of window*.

It makes absolutely no sense to discuss *another type of window* when the *siding is different, but the window type is the same*.

Okay, now let's go back up to your reply:

The ones that do get Vinyl "J" channels are caulked to the frame.


The "J" channel gets caulked to the frame.

Okay, now make those same "J" channels integral with the window ... where do you caulk them? Why? More to the point - How?

Now on to: Is the fiber cement siding caulked to the "J" channels?

Mike Schulz
11-02-2008, 05:56 PM
The original question was
New construction Hardie Board siding and vinyl windows. The windows are: MI Windows & Doors Model # 4300.

That is what I was trying to explain but the subject kept drifting to vinyl siding.

How do you caulk the channels. After the siding is installed you run a bead around the edge between the "integral fin" and face of the siding.

Now please explain each of the questions I posted to "Jay"
That all deals with the same window with the same siding with or without the fin.

Mike Schulz
11-02-2008, 05:58 PM
Before you answer when I spoke with MI they said the caulking doesn't void the warranty or interfere with the integrity.

Jerry Peck
11-02-2008, 06:10 PM
New construction Hardie Board siding and vinyl windows. The windows are: MI Windows & Doors Model # 4300.

None of the windows are sealed at the siding. The windows are flanged type "self flashing" if you believe in that, and have what the manufacture calls (integral "J" channel).


THAT was the original question: WITH the integral "J" channel.

You cannot address 'fiber cement siding' with a non-integral "J" channel window. You must address the window with the integral "J" channel, then address the siding being abutted to it.

Brandon Whitmore
11-02-2008, 06:14 PM
I think it's time for vinyl window manufacturers to design a proper self flashing window designed specifically for lap siding (wood, fiber cement, etc.). Picture a window that has pseudo step flashing on the vertical sides of the window built into the frame........

Ted Menelly
11-02-2008, 07:22 PM
If it has a integrated channel caulking the lap siding is not really necessary up inside that channel because the siding laps over it an 1 1/2 and the outside of the j laps over the siding. That all based on the proper lap of the water proofing membrane lapped over the lip of the J channel under the lap siding. As you bring the siding up to the bottom of the window you have the water barrier lapped over the top of the siding coming up to the bottom of the window and the siding going up the side of the window laps over that piece coming up to the bottom of the window as well.

As far as a window with no channel and caulking a J channel to it I would never trust that as a proper seal. That is something that would need constant maintenance to make sure the caulk has not separated and almost a guaranteed water entry point in a short time to come.

Ted Menelly
11-02-2008, 07:33 PM
I read Verns entire original post wrong. If you can use those windows for vinyl siding I see absolute no reason they cannot be used with hardi siding. It is going to serve the exact same purpose. As far a a flashing at the top. Why. It is already flashed. All this counts on the proper house wrap under the siding or water proof mebranes.

If the windows say for vinyl siding only then you would have a manufacturers installation instructions to deal with.

Jay Ray
11-02-2008, 07:56 PM
Mike Schulz,

Let me answer your question second as Jerry Peck made 2 very important points.

Jerry, the real trouble with PVC windows is expansion and contraction. It is very violent. I measured a window frame in the am and then again in the heat of the afternoon. The temperature differential was 40F and the 60" window changed 3/8". So to think silicone to seal a pvc window long term is dreaming. Now, you asked about a non-integrated flange. When you nail the flange to the wall it does not stop the constant expansion/contraction. The Canadians side screw the frame in the outside track top/center/bottom. This pins the frame to the home and lessens the exp/cont. some. It also stops the window from moving in and out, like the house is trying to breath....on the newer tighter homes when you slam the front door you will actually see the pvc windows move outward. (slightly). But on windy days the windows the windows really get a workout. So not only do you have the nail flange pulling out of its kerf when the pvc contracts but the unpinned windows move in and out. Look at any home to see the interior trim seems to have magically separated from the frame. The painter caulks the gap and the next year the gap magically reappears. The nails in the interior trim do not allow the trim to close to the frame.

To tape a window or door with the non-integrated flange you must back wrap it 1st! Turn the product face down on sawhorses. Starting at the TOP you place 6" (Min) tape on the outside frame running it into the corner and onto the back side of the nail flange. This will leave you with 3-4" on sticky side OUT tape exposed. Repeat the 2 sides but not the bottom. Carefully install the window letting the tape lay with the Not-Sticky side on the wall. When you have the window installed you then face wrap it. The tape starts on the side of the window, the 2 sticky sides make very good adhesion and if you used a 6" tape on the face wrap you will have 3" of the tape sticking to the wall. Back wrapping is also highly recommended for door products with 908 casing. Painters are supposed to seal the casing to the frame after installation but that is short term.

Here is the theory and it is pruven. if you face tape a non-integrated flange you are lucky to get 1/2" tape making contact with the window frame. The windows will "wriggle" out of it. (exp/cont.) So when you back wrapped and water gets around the face wrap you have created a permanent channel that will weep water to the sill and out.

Personally I remove the non-integrated flange if the windows are ready for side screws. Side screw and tape the window to the sheathing.


Pvc expands/contracts. Hardy board does not. So why are you hung up on sealing the outside of the siding from the flashing. Yes the siding company recommends it but that is more to cover there liability IF THE FRAME IS NOT FLASHED. The home still takes damage (slower) but when the law suite comes the siding company shows you sealed it, that the flaw was in the true flashing. Its called redundancy. You want a min. of 2 ways of sealing any opening. If one fails the other will great reduce the damage. Now if you install all windows and doors with a drip pan, tape the frame to the sheathing an PVC window can virtually leak forever as the water is really not running to the wood frame. As a homeowner if you gave the windows drip pans and the wall or window failed and the wood window rotted wouldn't it be so much cheaper to replace the window as the framing would stay dry. Not to mention bad leaks ruining Sheetrock, paint and flooring!

Here is the lost art of flashing corners. In the old days they used lead on all corners, windows, doors and roof. When it rains the lead leaches out very minute amounts of chemicals which act as a anti-fungal and a pest retardant. When Typar/Tyvek was invented bonehead contractors thought it was water-proof. It is (was) and air barrier until they stapled it and nailed siding. It is a water-RESISTANT material that is water permeable! So you must wrap the corners with a self-penetrate barrier-Grace ice and water. Then the house wrap must overlap a min 12" around the corners.

Did you know when you see water running down the face of PVC siding there is just as much water running down the backside. Water follows the nails and you get rot.

If you build a house right it only needs sealant for astetics only. When lead paint was around they used the paint to do most of the exterior joint sealing. Now that we have lost that ability some exterior sealant is needed.

I am working on 5 homes right now less than 10 years old. All have at least 60K damage to the windows, OSB and framing due to no flashing. If anyone wants to see the reports email me and I will send you the pdf. If you are a contractor using poor flashing methods you may wish to see the damage you are more than likely inflicting on your customers. The I have won 3 cases for the homeowner to date and more homes are coming out of the woodwork steadily now.

Jay Ray
11-02-2008, 08:05 PM
OSB-six months old. It was 1/2 but in now 7/8"! Did you know that osb is limited to 85f temps with a R/H of 65%? It should not even be sold up here in New England! Also when you cut an edge to fit it that cut edge is suposed to be sealed. So all your cut edges will soon look like this:

Jerry Peck
11-02-2008, 08:43 PM
Let me answer your question second as Jerry Peck made 2 very important points.

Jerry, the real trouble with PVC windows is expansion and contraction.


I was working through gradually to allow for thought time and consideration of each question, the answer, and follow-up question with its answer.

You are correct: Plastic of all types, especially PVC, has relatively large coefficients of expansion.

That's why "backer rod" (or bond breaker or release tape) is used (which you will notice I underlined in the post showing the Jeld-Wen After Installation instructions. The sole purpose of "backer rod" (and bond breaker or release tape) is to limit the adhesion of the sealant to two surfaces. As soon as the sealant is allowed to adhere to three surfaces, the sealants ability to be elongated (to compensate for contraction of the materials it is adhered to) or to be compressed (to compensate for expansion of the materials it is adhered to) is gone. That third side securely holds the sealant in place, causing the sealant to fail. All simply because the sealant is not being allowed to move freely.

I must disagree with this, though: "So to think silicone to seal a pvc window long term is dreaming."

Provided the PVC is compatible with the sealant being applied (not all sealants are made to be compatible with all materials, in fact, there are various sealants out there made to be compatible with various materials), but, for the sake of the discussion (and because it is the only presumption we can make, otherwise we are dealing with incompatible materials, in which case failure is not only an option, it is guaranteed) we will presume the sealant being used *IS* compatible with the PVC window and with the other surface, in this case the vinyl "J" channel (for windows which do not have the integral "J" channel).

*IF* (that is very critical) the sealant is stated as being compatible with the PVC window and with the vinyl "J" channel, and *IF* the space between the two surfaces being sealed is 1/4" minimum (typical for most sealants of decent quality), and *IF* the joint width/depth ratio is 2/1 or greater, and *IF* the joint depth is 1/4" minimum, and *IF* the joint depth is less than 1/2" (all specified for the major DOW sealants used on commercial windows), then the silicone sealant will elongate to 200% minimum and compress at least 50%.

Example one would typically find on a residence: 1/4" wide gap x 1/2" depth, with 3/8" backer rod pressed in place, the width of the joint is 1/4" (the required minimum width) and the depth of the joint is 1/4" (the required minimum depth). This does not allow for the 2/1 width/depth ratio, but those are minimum sealant conditions which are allowable.

That 1/4" width joint will expand to 1/2" minimum, and, most likely, to 3/4" with some joints to 1". With a joint on each end of the window, the required movement of your 3/8" window expansion is only 3/16" at each sealant joint.

Well within the ability of the sealant.

That sealant should easily last 20 years.

Provided it is applied properly.

Therein lies the catch, it is seldom applied "properly" on commercial high-rise jobs by persons trained in application of it, so to expect a non-trained person to apply it anywhere near properly is to expect a lot.

Meaning that failure is not only an option, it is a likely option.

The difference in what we are saying is that you are saying the material will fail, whereas I am saying the installation will fail.

Same net result, though.

Mike Schulz
11-03-2008, 07:11 AM
I must be terrible about explaining myself. My concern is not about the window installation in the opening of the wall. Lets say the window is flashed and perfectly installed in the opening.

My point is why would you not seal (caulk)the window to try and stop and limit the amount of water from entering behind the siding. You caulk the butt joints of the siding. You caulk all areas on the exterior except the windows.

When not caulking water enters the top of the window channel runs down the sides and behind the siding below it. This creates a wetter plane below the window and longer drying periods. If there are any penetrations through the house wrap this would be a entry point. Also on a hot summer day after a rain water turns to vapor when the wall heats up and vapor can go both directions through the house wrap. Why introduce more.

So "I" think there is two options for better performance. One caulk the window or two take the sill flashing and overlap the siding panel under the window so the water runs back out. Neither one of these are done here.

Mike Schulz
11-03-2008, 07:16 AM
When I spoke with MI they told me to follow the siding instructions. They also said it does not void the warranty if you caulk the windows. This is from james Hardi site.

General: James Hardie believes it is good building practice to seal the joints to prevent moisture, such as wind-driven rain and snow, from penetrating the wall cavity. Caulking around windows, doors, eaves and trim edges gives added insurance that leaks will not occur. When James Hardie siding products butt into wood-based materials, a 1/8" gap will allow for expansion and contraction of the wood-based product.

Caulks and Sealants: James Hardie recommends the use of caulks and sealants that remain permanently flexible. Look for the words 'permanent flexibility' or 'permanently flexible' written on the label or in the accompanying literature. Allowing caulks to dry for the recommended time will help to prevent paint from flashing and/or cracking over the caulked joint.

Mike Schulz
11-03-2008, 07:21 AM
Here is a good example of what I am trying to say. It has both vinyl and cement fiberr panels.
Window Flashing, Window Leaks and Window Leak Repair,How-to Pictures (http://www.albertsroofing.com/Window%20Flashing.htm)

Rolland Pruner
11-03-2008, 01:27 PM
I recommend calling the mfg., ask for some answers.
To caulk, flash better, leave alone??

Rolland Pruner

Mike Schulz
11-03-2008, 03:39 PM
Rolland that is the problem. The window manufacture doesn't care about the installation of the siding, only how the window is installed in the opening of the wall. I called, see first couple of post. The builder claims that they don't caulk the windows because it voids the warranty. MI says it doesn't but can't claim caulking or not should be done.

Jay Ray
11-03-2008, 04:58 PM
have you requested the manufacture send a tech out to the job site to inspect the windows? Not a salesman, but a factory tech.

Have you removed some interior trim to look at the R/O?

Is the integrated nail flange clipped to the window? If you do not know ask the manufacturer. If it is clipped on take some duct tape create a damn. Tape the sill so the tape is at least 1" above the level of the inside corner. Close/lock the window. Add water only to fill and cover the joint where the exterior cladding to the window frame. Pen mark the the water level. Give the window a few hours, check the water level. If it remained the same add water so the level immerses the bottom of the sash/sill joint. Mark the water level and return in a few hours.

It is highly unlikely MI uses a clip style ext. PVC exterior trim w/"J" channel receiver. It is way too advanced yet for the American window companies. Iv'e seen a few major companies try it and it was a total failure.

I told you this before, bring in a Infrared guy. He is not your competition he is there to help. You might find yourself linking up and gain work.

If MI refuses to send a tech, threaten to bring in a guy like me. At $1,000 min 3 days plus travel expenses they might loosen up a bit. Because if I find the issue is with the window or the contractor the customer will win a easy lawsuit for the aggravation.

Lets talk after you do the above mentioned items.

Did you ever ask the homeowner for pictures?

Vern Heiler
11-03-2008, 08:51 PM
First, thanks to all for your thoughts. I have not abandon this thread, but have been pondering the outcome.

Some of the conversation has wandered from my question, which was about the use of the vinyl window, with the integral ‘J’channel, and Hardie Plank siding. I was hoping for some sort of definitive answer in the form of code or manufacturers writing.

The windows referenced at the beginning of the thread are the only time I have seen this application. My first gut feeling was that it was not right but decided not to write them up as siding is siding, could not find anything that said it was wrong, and house wrap (water resistive barrier) should be there! Hope this was not something that will bite me latter!

I frequently see this type of window in vinyl sided homes and I have often thought it was an entry point for moisture, but I have not seen a problem due to the window. Plus vinyl siding has weep holes in the bottom of every course to let the water out and it is general knowledge that vinyl siding gets water behind it.

VSI (Vinyl Siding Institute)
“Water-Resistive Barrier
Vinyl siding has always been designed as an exterior cladding, not a water-resistive barrier.
Vinyl siding is designed to allow the material underneath it to breathe; therefore, it is not a
watertight covering. Because of its design and application, it provides a supplemental rain screen
that enhances the water-resistive barrier system by reducing the amount of water that reaches the
underlying water-resistive barrier.”

Hardie plank siding does not have weep holes and because it is relatively thin, water can lay on the lap behind the siding with little air space to evaporate. The Hardie installation instructions do not address window or other fenestration specifically, but do have a note at the bottom of figure 1.
"Leave appropriate gap between planks and trim, then caulk***"
http://www.jameshardie.com/pdf/install/install_plank_north.pdf (http://www.jameshardie.com/pdf/install/install_plank_north.pdf)

There is no way to caulk the top or sides of these integral ‘J’channel windows. As mentioned earlier in the thread, flashing is recommended at the butt joints (required on colored product), why would it be acceptable to leave the top and sides of windows wide open?

I hope I don’t see this installation again as I can see a big pi***ng match coming!

Jerry Peck
11-03-2008, 09:00 PM
"Leave appropriate gap between planks and trim, then caulk***"
http://www.jameshardie.com/pdf/install/install_plank_north.pdf (http://www.jameshardie.com/pdf/install/install_plank_north.pdf)


I am sure you also noticed that the "trim" being referenced was square edge trim, not "J" channel.

That makes a difference.

With square edge trim, you have two surfaces which can be caulked to.

With "J" channel, you only do not have any surfaces which can be caulked to.

Vern Heiler
11-03-2008, 09:09 PM
Jerry, where do they distinguish type of trim. Corner board trim, fenestration trim or windows?

The use of 'J' channel with Hardie siding is the whole question!

Jay Ray
11-03-2008, 10:14 PM
I have been a window and door technician for most every window company you can name. I have learned allot since 1995.

The window companies have successfully adapted to the nail flange technology started so many years ago in Europe. All windows are made for any finished product you can name. Siding does not effect the performance of the window. Brick, Stucco, PVC, Wood sidings do not change the window performance. (Unless the siding is installed wrong.) I had a contractor tell me you cannot install a window with a 908 PVC casing with the optional "J" channel. You most certainly can but I don't know why you would want to. Flash the window, brick up to the PVC leaving the recommended gap and try to do a beauty caulk job from brick to PVC. The window will not leak but it will look very bad. Won't bring pride of workmanship to the window, the builder or the mason. Its a lose-lose situation. The point is the window will perform to the specs it was designed for.

Now, I have charts and graphs that tell me 98% of all window failure is attributed to installation. I have been investigating issues enough to fully agree with the charts.

So it is 100% true this window is the correct window for Hardy Board. You would still have issues if it were any other type of siding. This I can guarantee you.

You need to remove the burden of liability off your shoulders and place it on the window manufacturer. They will (should) complete a full investigation which will utilize methods that limit you. (From what I understand you cannot conduct destructive and non-destructive tests?) If they refuse the homeowner needs to only mention the "L" word (lawyer) and they will send someone. If they find issue with the flashing or the installation method they will then either force the lumber yard to force the contractor to fix his mistakes or they will back away. My experience with this particular company tells me they will back away.

Now armed with the data from the window company you will have to have the homeowner force the dealer to force the contractor to fix his mistakes. That goes either way as well. The dealer holds little power over the builder and these slow economic times they can do little to force anything.

So that leaves the home owner to sue both the dealer and the builder. Now in order for the dealer to dodge the court cost (weather they are involved or not in the installation method), the dealer will offer free product if the builder offers free labor. After all the dealers know the court system will favor the homeowner and make all parties named in the lawsuit pay equal shares. Thus its cheaper to give the builder new siding.

The builder if he is a smuck will run and hide. This places the dealer in a particular spot. Depending on if they offered installation advise to the builder. After all, if the homeowner names only the dealer as liable and they only sold the product chances are the court will not see enough evidence to take it to court. But then again the dealer does not want a bad reputation and if they gave any installation instruction they may see it cheaper foot the bill.

All this is my opinion and it never plays out the same so I am just blowing smoke. The only true answer will be found when some siding is removed to show a lack on flashing. Do you have the authority to order this be done?

I can get that authority in less that 3 phone calls. I have felt your anxiety in this thread and it's time to ease your pain my friend.

Who is your contact at the window plant. I would like to pick his brain and talk turkey with them. I know for fact one of the major window/door companies state it costs $84K in attorney fees just to answer a lawsuit. This does not include preparing a case, just to file paperwork to respond to that notice of the impending lawsuit. It's time to start removing that weight on your shoulder.

What is your involvement with this? Can you conduct an investigation or are you bound by rules that limit you?

I'm getting very intrigued by this. I already can tell you where the water is coming from and why as well as how to perform a long term fix. The question is can you do anything to substantiate my theory?

Jerry Peck
11-04-2008, 07:01 AM
Jerry, where do they distinguish type of trim. Corner board trim, fenestration trim or windows?

The use of 'J' channel with Hardie siding is the whole question!

They do not distinguish the type of trim in the installation instructions, which is the problem.

However, their drawing, the one with that statement you referred to, depicts square edge trim, not "J" channel. Thus, at the very least (or maybe the very most, depending on your point of view) that statement is 'shown' as regarding to 'square edge trim'. After all, if you are using Hardieplank siding, they are presuming that you are also using Hardieplank/Hardieboard/etc for the trim.

The requirement to "caulk" the ends of the siding at the trim can be said to be met by sliding the ends of the Hardieplank siding up into the "J" channel.

The installation instructions are not specific for either the window or the Hardieplank siding, but that is to be expected. Consider this: If that window 'was to be used exclusively with vinyl siding', 'it would say so', on the other hand, if that window 'was not made for exclusive use with vinyl siding', there would be two choices: a) list each and every type of siding which is allowed to be used with the window, which would make for a very long list, or, b) don't say anything about the type of siding to be used with the window. The window manufacturer chose b).

How can you "properly" caulk the siding in that "J" channel? You can't. It is not made to be caulked. Thus, with "J" channel, you do not caulk whatever goes into the "J" channel.

But, one asks, what about the water which gets in with Hardieplank siding?

Another answers with, what about the water which gets in with vinyl siding?

Answer for both: BOTH *REQUIRE* a "weather resisting barrier" be installed behind them for that purpose.

In this case, with Hardieplank siding, look at that sane Figure 1 you referred to about "leave appropriate gap between planks and trim, then caulk***", you will notice that both types of wall construction shown also require "water-resistive barrier" behind the HardiePlank siding.

Thus, caulking inside the "J" channel become a moot point.

How about the water running down the "J" channel from the sides of the windows? Some will surely drain down inside, down the backside of the Hardieplank, and some will surely drain down the outside face of the Hardieplank. The water which does drain down the backside face of the Hardieplank in on the Hardieplank side of the "water-resistive barrier" which is required to be installed behind it.

I say "The water which does drain down the backside face of the Hardieplank in on the Hardieplank side of the "water-resistive barrier" which is required to be installed behind it." while the installation instructions say "A water-resistive barrier is required in accordance with local building code requirements."

Now the apparent next question becomes: Does your local code require it? The IRC does.

The next question, not as apparent, becomes: If my local code *does not* require it, do I need to install the water-resistive barrier?

The answer is: Yes. If you do not, you have not "properly" installed the siding. While that may be debated endlessly during code officials and inspectors and home inspectors discussion, the answer lies within the outcome when *you do not* install it and you go to court, when the judge says "You SHOULD HAVE installed it.", and "Now you get to pay the Defendant $xxx,xxx.xx to correct the condition.", the judge then asks a followup question, "How much would it have cost you to have installed the water-resistive barrier before installing the Hardieplank siding when you originally constructed the house? The difference between that and what you are now paying the defendant is what that cost you *for not having done it right when you built the house*."

$xxx,xxx.xx cost now
- x,xxx.xx cost then
$xxx,xxx.xx cost for not doing it right the first time ... to me, that is a couple of extra $xx right up there after the $sign which would not have been there. :eek:

I see I should have read Jay's post before responding to yours, as we said about the same thing all the way down the line, only we said it differently.

Mike Schulz
11-04-2008, 08:56 AM
Here is a link to some testing with and without caulk. I'm shocked at the results.


Vern Heiler
11-04-2008, 10:38 AM
Thanks Mike, good find. I would feel better if Hardie stated "or 'J'channel" but I can live with the fact that a study has been done.

Jerry Peck
11-04-2008, 10:44 AM
Here is a link to some testing with and without caulk. I'm shocked at the results.



Thank you, very good, and interesting, information.

However, there is a mis-statement at the end.

(on last page)
In fact, the building codes do not require a weather barrier when exterior grade sheathing is used.

A weather-resisting barrier is required by the IRC, regardless of whether or not sheathing has been installed. The exception for where a WRB is not required is for exterior cladding system which meet a specified test, and, if they meet that, then no WRB is required because, well, no WRB is required - the cladding system works without it.

Of course, though, that was done in 2002, and may be why the IRC now requires a WRB.

Jay Ray
11-04-2008, 11:55 AM
Very informative info here. I personally think the test was mostly mute as the house wrap in under the nail flange. Then again most contractors install it this way so the test shows reality in today's building methods

Jerry Peck
11-04-2008, 12:06 PM

Back when that testing was done, the code did not require house wrap, without housewrap (the weather resisting barrier), all that red staining on the WRB in those tests would have been 'on the OSB' sheathing.

I am sure you have seen a lot of windows installed where a WRB was not installed and the sheathing was rotted out.

To most of us, installing some type of protection over plywood or OSB is a "no brainer", but there are builders who build to "minimum code", which did not "require" it, so they did not use it.

Yeah, hard to believe some builders would such a thing, but many did.

Jay Ray
11-04-2008, 03:45 PM

Your right. Seems common sense just flies out of the window. I was brought in residential construction back in the 80's. We used felt paper on the walls and roof. Plywood. OSB and the new house wraps were not yet in use, at least in Texas. I was too young to know if it was code or not. I was taught code is a minimum to go by and if in doubt install to a level above code. I got in with conscientious builders which taught me look to long term to earn a living. These days, as well as even then, there were builders only concerned with the fast buck.