Replies

1. 
   frammer52 | Nov 07, 2009 12:33am | #1

   What brand?

   I am serious, different manufactorors have different requirements.   I think they do that just to limit liability.

1. 
   Proclive | Nov 07, 2009 02:28am | #3

   I think all the windows we have installed are Anderson.

2. 
   RedfordHenry | Nov 07, 2009 12:54am | #2

   Install sill pan made out I&W or vycor.  Level unit, usually start with the fat end of a shim under each side.  When level,  fasten head flange with one 1.5" roofing nail in the top corners.  Plumb, then fasten at bottom corners.  Double check for level and good tolerances between the sashes, jambs and meeting rails.  When all is good, nail off the rest of the flange, about one nail every 8" or so.  Shim all corners on the sides and top.  Also, shim in the middle on all sides (sometimes I don't shim the middle on the tops and sides if the unit is less than ~2' wide).

   Vycor (or equivalent) flashing tape, sides flanges sealed first, then the top flange.  No flashing tape on the bottom flange.  Healthy bead of silicone around the entire unit where the flange meets the jamb, then exterior casing (rabbeted on the back to accomodate the flanges, otherwise casing doesn't sit flat).  Cut all shims back to framing.  Foam, chink or seal between the unit and rough opening as necessary.

   In the olden days, I have laid a bead of silicone behind the flange, but generally don't anymore, as long as I'm using self-adhered flashing tape.  Seems redundant, and it can be messy.  There's nothing as aggravating as a smear of silicone splooge all over your tools and hands when trying to install a $400 window.  

1. 
   Proclive | Nov 07, 2009 02:29am | #4

   So you don't fill every nail hole? Is the reason for no seal tape at the bottom because it will catch water?

1. 
   AitchKay | Nov 07, 2009 02:41am | #5

   RH believes in "Shingle Theory". It's a religion.The proponents of Shingle Theory think that if you layer from bottom to top, with each successively-higher course lapping over the one below, your odds of avoiding leaks are better.Taping over the bottom flange is redundant, because the sill pan has already done the job, and has been lapped over by the sides to complete the sealing of that edge.Window installation is SO much better now than when I started out in the 70s, thanks to flashing tape!AitchKay

1. 
   YesMaam27577 | Nov 07, 2009 02:59am | #6

   >>"Taping over the bottom flange is redundant, because the sill pan has already done the job, ...."(Not arguing here, since I install windows in new work about once every never..... but wanting to ask....)Although taping over the bottom flange is putting vycor over vycor, the sill pan does not absolutely prevent water intrusion between the sill and the bottom of the wondow.Isn't the sill pan plus the added layer a bit like flashing and counterflashing? Where both layers have a purpose?

   I won't be laughing at the lies when I'm gone,
   And I can't question how or when or why when I'm gone;
   I can't live proud enough to die when I'm gone,
   So I guess I'll have to do it while I'm here. (Phil Ochs)

1. 
   RW | Nov 07, 2009 03:06am | #7

   I would argue that taping over the bottom would prevent the sill pan from doing its job - that any moisture which did get in, from anywhere, would have no exit. Everything you've done to the opening thus far has been designed with the idea that water must exit, and you're building the path of least resistance, even if it is a "just in case" scenario. Then you put a road closed sign at the end. Water is stubborn. It'll go off road at that point.

   At that point you're no different than the guys that just tyvek tape the fin to the housewrap and walk away. Real trucks dont have sparkplugs

2. 
   YesMaam27577 | Nov 07, 2009 11:41pm | #24

   >>"I would argue that taping over the bottom would prevent the sill pan from doing its job -...."Excellent point -- thanks for the minor correction!

   I won't be laughing at the lies when I'm gone,
   And I can't question how or when or why when I'm gone;
   I can't live proud enough to die when I'm gone,
   So I guess I'll have to do it while I'm here. (Phil Ochs)

2. 
   RedfordHenry | Nov 07, 2009 04:37am | #9

   Don't need to fill every nail hole. In fact, I don't use the nail holes at all. I nail between the holes. Leaving the flashing tape off the bottom allows an exit path for any moisture that does might in, although if water is getting past the taped flanges, there are other issues to address.I didn't see others posts before replying. David Meiland's description is right on. I've done the beveled "sill pans" when I had some siding on hand, but I haven't made it a habit yet (though I think I will starting NOW!).

   Edited 11/6/2009 8:41 pm ET by RedfordHenry

1. 
   fingersandtoes | Nov 07, 2009 04:46am | #11

   Our code has made a 6% sloped pan mandatory. I guess it is a good idea. I never did them until I had to.

1. 
   RedfordHenry | Nov 07, 2009 06:15am | #14

   Any idea on the slope of a piece of 1/2x6" cedar siding?  I suppose I'll go get my Construction Master calculator out of the truck though I won't be surprised if it's 6 degrees.

2. 
   davidmeiland | Nov 07, 2009 06:44am | #15

   Worth noting that adding a piece of 1/2 x 6 bevel siding to your rough sill will often cause a too-tight fit of the window, if you framed the RO to manufacturer's specs. When I'm framing I frame the rough sill 1/2" low, if I'm retrofitting I've been known to get out the skilsaw and power plane and butcher myself a slope to the existing sill.

3. 
   Gene_Davis | Nov 07, 2009 05:16pm | #16

   Let's say it is 1/2 at the butt and 1/4 at the thin and that it is exactly the 6" you need to sit atop a 2x6 sill with 1/2 sheathing.  That is a 1/2 in 12 pitch, and the water we have in these parts will flow down that just fine.  Yours may vary.

     

   View Image

   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985

4. 
   DickRussell | Nov 07, 2009 06:31pm | #17

   1/4 inch over 6 gives only 2.4 degrees; over 5.5" gives 2.6 degrees. For 6 degrees you'd need about 5/8 inch over 6", or 9/16" over 5.5". A quarter inch over a 3.5" stud width would give you 4.1 degrees. For 6 degrees and 3.5" stud width, drop would be about 3/8".The above has to make you wonder where they got the 6 degrees.

5. 
   davidmeiland | Nov 07, 2009 06:44pm | #18

   Cedar bevel I use tapers from about 1/8" to 1/2" over 5-1/2". You can pour water on it all day and it will run off. It's equivalent to about 3/4" per foot, more than plumbers want in their horizontal drains.

6. 
   Gene_Davis | Nov 07, 2009 06:44pm | #19

   What is the recommended pitch for the typical sewer waste line running from house to public or septic?  And there is more than water flowing in that line.

   My point is that any old clap will do as the under-window substrate for mounting the membrane onto. 

   View Image

   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985

7. 
   DickRussell | Nov 07, 2009 06:57pm | #20

   "My point is that any old clap will do as the under-window substrate for mounting the membrane onto."Agreed. I was just curious as to where the Vancouver 6 degree spec came from. As someone else noted, I would have thought it was what you got with a typical clap on the rough opening, the code writer thinking, "Yup, that sounds about right." Maybe he screwed up the calculations in getting to 6 degrees.

8. 
   davidmeiland | Nov 07, 2009 08:32pm | #21

   A pitch that's much more than the 1/2 x 6 clap is going to cause problems, as the nail fins won't easily reach at the top and/or bottom. Doing it the way I do it, using the windows I use, we are stretching the height of the RO on the outside to the max, and going further could start to mean a loss of nailing.

2. 
   davidmeiland | Nov 07, 2009 05:58am | #12

   The moisture in the sill pan probably won't be getting in past the flanges, it will be getting in thru the joints in the window jamb itself, or thru the joints between the aluminum cladding and the wood if you're using clad windows (which is mostly what I use). The smart move is to plan on the eventual failure of the window unit (whether partial and never detected, or catastrophic and obvious) and protect the frame of the house from the water that will get thru when that happens. I have seen brand new expensive windows leak right thru the frame during windy rainstorms... and I mean a window that was received, unpacked, and installed the day before. All it takes is some guy at the factory stopping his sealant gun for a second to change channels on his ipod, or whatever...

   I still see ridiculous window installations quite often, in spite of the many available products for sill pans and flashing. My lumberyard tells me I am the only one to order Flexwrap from them. Granted you can make a decent pan out of Vycor but for whatever reason I like spending stupid money on the Flex (about $2.50/LF or $15 for the average window hole).

3. 
   AitchKay | Nov 07, 2009 06:04am | #13

   Ditto re adopting David Meiland’s bevel siding trick -- I think I’ll start doing that, too.And as I look at a few more posts, I see that fingersandtoes has found that mandatory.SOP from here on out, I guess.AitchKay

3. 
   davidmeiland | Nov 07, 2009 03:17am | #8

   RH's description is similar to what I do. Backing up a little bit... install felt up to the window opening, the install the sill pan (usually made out of flexwrap over a piece of cedar bevel, sometimes out of galv or copper sheet), the continue felting, folding the felt into the window opening and lapping over the pan (the pan comes several inches up the sides of the opening). Stop felting at the top of the opening, leaving the sheathing showing. Install the unit on a couple of shims at the bottom, leveling/plumbing/squaring it up, nail every 6-8" or so. If operable, open and close and check for smooth operation, remove any shipping blocks. Tape the side flanges to the felt with 9" Vycor, extending up past the top of the unit several inches. Tape the head flange to the sheathing with same. Continue felting above unit, usually notching a piece of felt so that it sits down over the unit a few inches or more. Go inside and shoot in Hilti low-expanding foam, trying to keep it from adhering to the back of the flanges, especially at the bottom.

   I should say that most of the windows I have installed in recent years are Loewen. Their metal nailing flanges are the bomb. Vycor sticks to them like crazy, so you can waterproof with a lot of confidence. Have also installed some Marvin units recently, their flanges are flimsy plastic and aren't continuous around the corners (they provide these cheap like patches to use at the corners). My procedure is similar except I try to roll the Vycor onto the sides and top of the unit rather than just sticking to the flanges.

4. 
   Hudson Valley Carpenter | Nov 07, 2009 04:42am | #10

   I have never caulked the back side of a flange ever, which has me worrying.

   That's OK...as long as you installed the flange gasket caulk isn't required. 

5. 
   jimAKAblue | Nov 07, 2009 09:09pm | #22

   I don't believe that every window needs all the wrapping that everyone is now preaching.

   In my career, I set 95% wood framed, wood brick molded windows. There is no way to "tape" over the brick mold, yet these windows do not leak.

   Hmmmmm?

1. 
   davidmeiland | Nov 07, 2009 11:25pm | #23

   How do you know they don't leak?

1. 
   jimAKAblue | Nov 08, 2009 05:10pm | #25

   Because we properly caulked them where the brick meets the siding.

6. 
   woodway | Nov 08, 2009 09:22pm | #26

   Lots of good comments here but question: Does anybody spray a water on the flashed window after install to check for leaks? Locally, we do a lot of stucco exterior and before the stucco is applied over lath, I've gotten into the habit of squirting a water flow around the installed window, check for leaks around the window on the inside. A flashlight (from the inside) at the bottom has saved me a lot of call backs later and found more then one leak.

1. 
   davidmeiland | Nov 08, 2009 09:34pm | #27

   It's not a bad idea, but a garden hose doesn't fully simulate what happens during a storm. We get a lot of very windy rainstorms during the fall and winter, and a strong wind blowing over your building will draw a vacuum inside that will pull water in thru cracks that otherwise won't leak. One thing I like about foam around windows (or well-installed backer rod) is that it prevents the gap around the window from being an air entry point, and makes it less likely that a vacuum will draw water in thru that gap.

   The last window I water tested I did this: set up a stepladder outside the window and taped a garden hose and sprinkler head to it, so that the sprinkler was fully coating the window and wall around it with water (sometimes more than one sprinkler is needed). Then, set up a pair of box fans in the house, one about three feet from the window pulling air away from the window and blowing it towards the door, and the second in the doorway blowing out of the room. I was able to find a leak thru the window frame itself that way. A blower door setup would be ideal for this type of leak detection.... either that or a firefighter's vent fan.... those bad boys move an unbelievable amount of air.

   http://www.unifireusa.com/dsseriesppv.php

1. 
   woodway | Nov 08, 2009 10:11pm | #29

   That's about what I've done, no fan etc. but wide angle spray from a hose on the outside while someone on the inside is checking for leaks. If you want to be complete and go the extra step, then fans and neg pressure are good approaches. I just want to do a final water test to expose any (most) of the possible holes and leak spots that may have been missed. One of the worst I found was when we (actually a plastering sub contractor) applied foam trim to the bottom of all the windows after the windows were flashed and lath had been applied. We thought we would check to see if we had any leaks before the stucco was applied. That Styrofoam window detail applied to the outside acted like a damn and funneled water directly under the windows and about half the windows had to be reflashed and retested before the scratch coat was applied. Thank god we tested because after 3 or 4 years there would have been major damage to the walls around the widows. The leaks weren't just drip drip drip but rather more like a steady micro-stream of water running down the interior of the wall.

7. 
   mmoogie | Nov 08, 2009 10:05pm | #28

   Housewrap cut on the diagonal out of the bottom corners, cut horizontally at the top corners straight across the top of the RO. Fold in the flaps. Piece of bevel siding on the bottom (make the RO 1/2" taller than mfg recommendation) 9" vycor along the bottom folded half into the RO, half down the face of the sheathing, 18" piece of 9" flexwrap over the vycor on the bottom, around the corner and up the sides about 9". Vycor up the sides. Nothing across the top, tuck drip cap under the housewrap at the top.

   I have done about 2 flanged windows in my life. Almost always doing wood 5/4 x 4 or wider casings with a large wood drip cap covered in copper flashing that tucks under the housewrap.

   If I was doing flanged, I don't think I would tape the bottom flange for all the reasons mentioned in previous posts.

   Steve

   
   

   ---

   Edited 11/8/2009 2:08 pm by mmoogie

1. 
   mmoogie | Nov 08, 2009 10:25pm | #30

   Here are a couple of pix of some 190-yr-old window frames going onto new openings flashed as described.

   View Image

   View Image

   
1. 
   davidmeiland | Nov 08, 2009 10:40pm | #31

   Uh-oh... I've heard that Typar does not work upside down.

1. 
   mmoogie | Nov 08, 2009 10:50pm | #32

   It works, but the rain has to be flowing uphill...plus it voids the warranty.

1. 
   davidmeiland | Nov 09, 2009 12:52am | #33

   Since the rain blows uphill during the real storms you should be perfectly protected. The rest of the time the housewrap doesn't get wet anyway.