Vinyl siding


Is it just me or is there someone out there think there is something wrong with the way the siding is attached around the window. The home is about one years old. If someone has any information on a link that I could use for general information on the correct way to install vinyl sinding , I would appreciate it.

Bruce MacInnes


Great resource on vinyl siding. VSI

Oh yea, that’s wrong!

First it appears to have improper flashing around the perimeter of the window casing. With the vinyl install it is missing the J channel. Both of these will allow water, air, and insect penetration.

Very wrong! Also very important is whether or not the window was properly flashed prior to the vinyl siding installation. I find most are not. Without the proper flashing even with the J channel the water will end up being diverted into the wall around the window and door openings. Just from looking at this I would bet the installer did not know what they were doing or just plain lazy (and cheap). I hate vinyl siding because it may look good from the exterior, meanwhile all kinds of things could be going on behind it. CYB well on this and any future ones like it.

Michel, Thanks for the information.


The only thing wrong with it is the siding may be cut a bit too short. The siding should be cut about 1/4" shy to allow for expansion and contraction. If it’s cut too wide or if the siding has shifted from side to side the gap your photo shows will occur.
The window in the picture is of the type that has it’s own built in receiving channel and therefore requires no “J” . What you see in the pocket of the receiving channel does ,in fact, appear to be flashing.
If the flashing had been stuck on just 1/4" away from the angle of the pocket the installation would have looked much better.

I disagree. The window casing should be flush against the side of the house, with J channel then applied to the side. There should not be a 1" space between the trim and the side of the house. This would allow snow, ice and everything else to to get behind the casing.

That’s not casing. That’s the newer style windows many builders are using now. They have built in J channel, sorta like the J-blocks people use for lights and hose spiggots. Pretty slick.

That window is called a new construction window in my neck of the woods. The J channel is built into the window frame and has a nailing flanged that protrudes away from the frame and is under the siding. To flash this window we use a product called Vicor which is basically ice and water shield and it come in 6", 8", or 12" rolls. Once the window is installed you apply the Vicor over the nailing flange starting at the bottom of the window, then up the sides and the top last.

One important thing to remember is, in order to complete the building envelope the top of the window nailing flange must be under the building paper and then the Vicor can be installed.

The picture posted here you can see a bit of the Vicor against the window frame, it is black just like ice and water shield. I see nothing wrong with this installation other than that.

It doesn’t look slick to me, it looks cheap, that space is still going to cause problems. What happens when the siding slides back and forth? which it will, you will need to keep straightening it to hide that ugly gap that will show the insul. board, like in this picture, behind it.

Thanks for the info, but to me it looks ugly. There is too visible of an opening that lets you see the gap between the siding and the window and it makes the window look like it is just hanging there.

Chris, I have owned my own construction business for 23 years and I agree with you, it is ugly! I am also a certified building science thermographer and this installation, done correctly is more efficient than installing a window with wood casings and J channel.

That being said, it is cheaper, faster, thus more cost effective when building and the window MFG. can mass produce these windows in common sizes.

Next time your driving around, take a look at new construction houses in your area, you will no doubt notice that the second floor windows and the first floor window are the same size and appear to be large, the reason for this is they are all new construction egress windows, 6/6 grids, built in J channel, vinyl sided houses. This kind of building practice has been around for years and it allows a builder to budget X amount of windows at X amount for a price and build X amount of houses thus you have cost control or standardization.

Hope this helps.

Here’s an interesting link.

After reading your previous description it sounds like it would be a lot more efficient with this type of flashing. Also it would only cost about $20.00 more per window, but why couldn’t you still install J-channel, even if it was just for appearance. I’ve installed a “few” :wink: squares of vinyl. I would, it would look a lot better.

I suppose you could but most builders will not do the extra, also, many homes today will have vinyl shutters installed and then you will never even notice.

Now that I blew up the picture I can see what your talking about Peter.

Now it really looks like crap! :slight_smile:

Just wanted to thank everyone for their input. It has been very helpful.

Bruce MacInnes

Peter has it correct, IMO, especially about the top nail fin being under the building paper and the use of Vicor. Now, if the installers would do it right and make it look good…

That will be the day…