View Full Version : Single Wall Window Installation

Mike Drorbaugh
04-24-2007, 09:26 AM
The sale of this new house was nixed because the presale inspection report stated that window install was inadequate because it did not have flashing. I wonder if such a comment would be made by other inspectors. Photos are of the LP SmartPanel siding being removed to view the window installation details. While I can see things that could be "better" I believe they fall under the catagory of "good, better, best" rather than "inadequate, misinstallation, or code violation." I guess I'd like to know if other inspectors would have dinged the builder for the window install? Your comments, observations would be appreciated.

Jerry Peck
04-24-2007, 11:20 AM

First, welcome to THE inspection forum.

Second, is it your opinion that this installation is/was "okay" or that it is/was "not okay".

That information is needed for proper responses to inquiries.

Yes, things *can ALWAYS be better*, so 'good, better, and best' really are incorrect terms.

The correct answer to your inquiry, though, is:

A) Does that installation meet the requirements of the building code in effect in YOUR AREA as MINIMUM installation requirements go?

B) Does that installation meet the requirements of the window manufacturer as MINIMUM installation requirements go?

C) Does that installation meet the requirements of the flashing material manufacturer as MINIMUM installation requirements go?

D) Is that house advertised and being sold as MINIMUM HOUSING which meets MINIMUM REQUIREMENTS?

If the answer to D) is 'Yes.', then those MINIMUM standards are all which need to be met, and would be considered your 'good' standard.

If the answer to D) is 'No.', the house is being advertised and sold as something better, say 'Luxury', 'Upgraded', or some other term which states that the house is 'better' than 'minimum', then the requirements in A), B), and C) are simply "starting points" and not "acceptable levels of installation.

Does that help toward the answers to your question?

Jerry Peck
04-24-2007, 11:24 AM
To put this into a separate post.

From the IRC.


- - - R613.1 General. This section prescribes performance and construction requirements for exterior window systems installed in wall systems. Windows shall be installed and flashed in accordance with the manufacturer’s written installation instructions. Written installation instructions shall be provided by the manufacturer for each window.

wayne soper
04-24-2007, 02:34 PM
Jerry, Are you saying we should be reading the directions? What fun is it if we use the directions.HAHA

Gunnar Alquist
04-24-2007, 02:43 PM
My guess is that the inspector reported the lack of head flashing. It is not possible to determine whether a window is flashed with a non-invasive home inspection. We (HIs) typically do not remove siding or trim and the flashing (except for the head flashing) would not be visible.

Michael Thomas
04-24-2007, 03:26 PM
Here are the instructions for (for example) Anderson sliders; self-adhesive flashing over the house-wrap installed in the correct sequence is the method shown - no additional head or other flashings.

However note that Anderson puts the responsibility for flashing design and performance back on the architect / designer / builder / cladding manufacturer. So the inspector may have had valid reasons for calling for more rigorous measures than the generic flashing instructions supplied with the window, depending on his/her experience and or local requirements and practice.


BTW, I had not read those instructions for a few years and had forgotten (if it was even in there when I last read them) the caution against installing reflective flashing under vinyl . Seems I learn (or re-learn) something new here every day...

Michael Thomas
04-24-2007, 03:32 PM
Sorry, forgot the instructions:

Jim Robinson
04-24-2007, 04:36 PM
I don't know if it was right or not, but we never added flashing on a vinyl or metal clad window like that one in the picture. I don't ever remember actually having instructions with the windows, but I'm sure they were there on the job site somewhere. Then again, not a lot of rain here, either.

We would caulk the exterior trim boards around the perimeter of the window, and the top of the upper trim board.

Jerry Peck
04-24-2007, 05:53 PM

Without the benefit of the installation instructions for that window or that peel-and-stick flashing, what I see is the following:
- The wood siding above the window is too tight against the top of the window and will rot out.
- The water which gets behind the wood siding at the top of the window has no way out other than to run down the back side of the siding and, hopefully, out over the lower siding. And to do so, hopefully, before causing long term water damage to the siding (i.e., rot the side out from the back side).
- The wood side along the sides of the windows only add to this water-behind-the-siding-and-no-place-to-go problem.
- Once the water is behind the siding and gets down to the bottom of the window, there is no place for the water to drain out, so the water must continue down the back side of the siding.
- Then there is the additional water which can get in along the bottom under the window.

Did the inspector make the correct call? With no visible flashing, the builder (you?) would need to provide evidence that the window was flashed properly, i.e., with installation instructions on how to install and flash the window and from the peel-and-stick flashing.

The code basically just says 'make it work' and the manufacturer's installation instructions say 'this is how the window was installed when it was tested and passed the test to get the rating for this window installation', i.e, 'this is how *to make it work*'.

Jerry Peck
04-24-2007, 05:57 PM

I wanted to ask this, but wanted to keep it separate from the flashing discussion ...

When you install siding like that, where one piece overlaps the lower piece, how is it nailed to the wall so the upper piece is not flopping back and forth or nailed tight such that the upper piece bends in to the wall and out over the lower piece?

Is the wall framed straight up and down (plumb) or is the wall framed with a step out so the upper siding hangs out and over the lower siding.

Now that I have seen your photos, that raises more questions than just the flashing around the window.

Thom Walker
04-24-2007, 10:04 PM
After looking at the LP Smart Siding Installation instructions again, I think the Inspector may have made an understandable, but not necessarily correct call. Then again, I wasn't there, so I don't know what he saw that I can't see in the pictures. LP Smartside has a pretty clear installation guide and a very clear manufacturer warranty void statement. The key would seem to me to be if the windows are self flashing; and the one pictured does appear to be. Was the Inspector's call a valid one? I think that's the wrong question. It should be " who can defend his position with respect to the manufacturer instructions and his local code?


I think it also answers your questions regarding horizontal laps and nailing patterns. It seems to me that all that banding could add a lot to the cost of a siding job.

Several years ago I used this stuff to replace rotted T-111 on one side of my house. Typical for me, after starting to paint, I realized I had used non-paintable caulk. It takes a lot longer to remove than to install caulk.

Jerry Peck
04-25-2007, 06:21 AM

One of the problems Mike just ran into is that, when one exposes the way they did something to prove it was the correct way, they expose that installation and previously unseen and not accessible areas to the viewer.

In showing us the peel-and-stick flashing around the windows, this is now visible (from the guide you linked to):
(bold and underlining are mine)

- - Seal all gaps with a high-quality, paintable sealant with a stated service life of 30 years. Follow the sealant manufacturer’s instructions for application and backer rod requirements. (Jerry's note: Typically, this means a 1/4" or so gap for the backer rod, then the caulking. On the next page I see they are specifying a minimum 3/16" gap for lap siding. I do not see where a backer rod was used.)

- Flashing, Windows, Doors & Openings
- - All openings must be sealed, caulked and/or flashed in a manner that prevents moisture intrusion or water buildup. Several examples that accomplish this are shown on the following pages. (Jerry's note: Such as on the top of the window.)

- Finishing instructions
- - DO
- - - Paint all siding surfaces including drip edges (to me, that means to paint the cut edge above the top of the window and the cut edges beside and under the window)

- LP SmartSide Panel Siding
- - I see where either method of horizontal joints is acceptable, the 'Z' flashed one and the stepped out method. I am assuming that the stepped out method was used as I can see the studs and the bottom plate along that edge.
- - Self-Flashing Windows - Shows a trim around the window which is foam or putty sealed to the siding, however, in the photos, the untouched windows do not have any trim around them.


That's what it says.

Did the inspector make the right call? As Thom said "I think the Inspector may have made an understandable, but not necessarily correct call."

HOWEVER, in making that incorrect call (incorrect because the windows are - 'appear to be' - self-flashing), the inspector made the correct call because the siding was not installed properly (which the inspector did not know).

The problem, as I see it, is that while verifying the self-flashed windows and peel-and-stick flashing were done, other problems were exposed. Problems which will exist all the way around the house at each applicable location. Problems with the siding installation which are not in accordance with the installation instructions and which will take considerably more work to correct.

I wish my 'mistakes' would end so 'positive'. :rolleyes:

Mike Drorbaugh
04-25-2007, 06:03 PM
First, let me thank everyone for your opinions, they're useful and as usual, insightful.

As to the window install. At the time of the inspection the only visible "deviation" was the absence of a head flashing. According to LP SmartSiding and Jeld-Wen Window installation instructions, a head flashing is not necessarily required. LP shows a detail with a head flashing when a band board is used above the window and w/o a head flashing when no board is above the windows.

Some of the other issues: how much spacing is required between wood siding and window? The typical installation instructions are for a 1/8" gap for panel siding. Again, the LP instructions are a little ambiguous showing both a 1/8" gap in one picture for "self flashing windows" and in other places stating the need for "a 3/16" gap where siding ends at the trim around doors, windows and other openings." Practically speaking, do you really want to make an issue of 1/16" of gap--especially when it is not clearly stated? Backer rods behind caulk... are you kidding? How often do you see that in residential installations and how often do you point it out as "not according to manufacturers instructions" in your reports?? Myself, I would not unless it resulted in some obvious problem and clearly there was no obvious problem visible.

Jerry, you comments about the gap between window and siding at tops and sides being so close that siding will absorb water is noted but rarely leads to rot in Pacific NW climate. It's not unknown, but not really a big problem. As for no place for the water to go except down the back of the siding--well that's true and that is the way the panel siding wall works. What you are asking for is a rain screen system, with the siding attached to sleepers or lathe which is over the weather resistive barrier that leaves a capillary break (small gap) or a ventilation gap (1/2 - 3/4"). A rain screen system is a quality wall system but is rarely built, not demanded by building codes and exceeds requirements of the siding manufacturer. Lap siding on the other hand, is kind of a ventilated system without sleepers do to the configuration of the siding itself but the water still goes between the back of the lap siding and the weather resistive barrier.

Frankly, this installation was pretty good as window installs go, at least around here. Moreover, in talking to other APA field reps around the country I don't think this install worse than most. Now, having said that there were things that could have been better that were noted after the siding was removed. 1) the peel and stick at the top of the window should be under the weather resistive barrier rather than over it and 2) there was no sill flashing--the window sits on the bare wood framing at least at the bottom corners of the window where the angled cut of the weather resistive barrier wrapped up over the bottom window sill does not reacy. A sill flashing is RARELY installed. I'm not saying that is right, but that's the case.

FYI, the house passed all it's code inspections.

Again, thanks everyone.

Dave Hatter
04-05-2009, 07:54 AM

LP has a 7/30 year smart lap siding warranty.

LP's has specific written warranty and installation information & procedures.

LP specifically states that there installation procedures have to be done according to their specifications. If not, the warranty is VOIDED! period.

Warranty issues on this four year old house with the smart/lap siding are the following:

1. No 3/16" minimum gap at all siding butt joints and at most butt joints where the siding butts to the exterior trim. LP requirement.
2. Code violation with the local building inspector for improper attachment as siding is bowing/buckling at the bottom side of the siding.
3. 300+ face nails need to be caulked & painted. LP requirement.
4. Siding not installed correctly at sloped roofing. LP requirement is 1" minimum from roof shingles. Siding is touching roofing.

Most all Home Inspectors will not have the written siding warranty & siding installation procedures during their inspection.

In my opinion, the Builder did not install the smart/lap siding to the manufactures installation procedures and has violated the siding warranty by doing so.

The home owner is in litigation with the Builder. This is a very real problem and I believe the Builder should take responsibility and remove and replace all the LP smart/siding due to improper installation.

Please provide any comments or suggestions.

Thank you,
concerned home owner

Brandon Whitmore
04-05-2009, 10:28 AM
Did the inspector make the correct call? With no visible flashing, the builder (you?)

Jerry, Mike's profile shows that he is an APA field rep., so I doubt he was the builder on this.

Mike, I assume you were called out to evaluate the installation and make a definitive call as to what (if anything) needs to be repaired?

Jerry Peck
04-05-2009, 02:46 PM

Yes, I was aware of that, however, if you look at the installation instructions Thom provided a link to, you will not see the siding lapped as that siding appears to be in the photo.

Additionally, you will see that those installation instructions specify a 1/8" gap between the bottom of the siding above the window and the top of the window while the photo shows the siding tight to the top of the window. Another option is to use a flashing there, but that is just "an option".

Based solely on those two things, I would not state, as Mike did, "While I can see things that could be "better" I believe they fall under the catagory of "good, better, best" rather than "inadequate, misinstallation, or code violation." ", I will agree that things could have been "better".

Brandon Whitmore
04-05-2009, 09:29 PM
Sorry Jerry, I just realized this post is fairly old.
I was only posting because I had thought that you believed Mike to be the builder.

Ted Menelly
04-06-2009, 07:10 AM

The siding is to tight at the top of the windows. I cannot see just from looking at these picks the other items he is talking about.

I certainly feel by the explanation that things can be corrected by the builder with out litigation and law suites and, and, and.

Could things have been done better around the window, sure.

My biggest question is.

Whats with the little hard hats to pull some siding off from around a window. Oh, I know, something might fall off the roof. I think those picks alone are for the sake of the suite showing how wonderfully proficiant the investigstors are and why can't everyone be like that.

That is an example of things going to far and it sounds like this is where this law suite is going.

The cheap home buyer deciding to go with LP siding shows the mentality. Cheap is what I can afford and what I want but I am going to look for everything to be perfect or else. I can afford an investigation and law suite and I am going to go after you with everything I can and spare no expense :confused: The window is flashed just fine. I did not see caulking around the window and that should have been done on every window. Was that the tightest winow in question so it is the window they picked to exemplify their cause?

Way to many questions here Mike. To many questions to give answers to.

I am also curious why these questions from you are being asked here. Are you trying to get a general concensus for your cause, because you are not sure that your cause has enough teeth.

Again. To many questions

Mike Schulz
04-06-2009, 12:22 PM
Whats with the little hard hats to pull some siding off from around a window.

OSHA.......Also many job sites won't let you on them with out one.