Flashings, Leaky Windows, House Wrap, Etc

[Allan Edwards]

Re: Flashings, Leaky Windows, House Wrap, Etc

Dick, I’m not a scientist but I’m just not worried about Tyvek being compatible with the peel and seal window wrap membrane product. My stucco contractor uses the Jumbo Tex too. The two layers of Tyvek (one being Home Wrap, one being Stucco Wrap), with the Jumbo Tex as the third layer, I believe gives me a pretty good system.

However, the key I believe is flashing being installed properly and the window pans. I would guess 95% of leaks are around flashings and windows, not out in the field. I'm taking the postion windows may leak, I want to keep the water out of the house. I am thinking about on all of my stucco homes, putting in a 2x6 brickledge, and setting the bottom 2x6 plate of the exterior wall in the drop. That way, god forbid, if any water ever gets in the wall at least it stays out of the house. What do you think?

I am using the Tyvek 7” wrap under the pans (probably needlessly), with 2 layers of membrane (one before window is installed, one after) peel and seal on the vertical sides, and one layer on the top for head flashing.

My framer is one of the best I’ve ever seen. I’ve used him for 12 years. He is one of the more expensive here, his price per ft is from $5-$10/ft.

The house he just finished was not complicated as far as the roof, but it did have 11’ ceilings, 13/12 pitch, lot of arched openings (I counted over 50 today), several eye-brows, one set of round stairs going 2 stories, 1 set going 3 stories, another going 2 stories. He installs all windows and doors, cornice, decking. He’s great on detail (blocking for bath accessories, dropping sub floor for tile, following engineer’s design, framing for elevator, knows the code, etc). I’ll try to post some pictures. By the way, he has a daughter in pre-med at Rice University, another studying law at U of Houston, owns a home here and in Acapulco, has 3-4 fairly new decked out work vans, of course all the tools you can imagine. I believe he came here from Mexico in 1980.

[Dick Seibert]

Re: Flashings, Leaky Windows, House Wrap, Etc

Allan:

I too am not too worried about compatibility, I made the phone call to Du Pont and I didn't get a definite "no", so I've gone ahead and used the FlexWrap.

My problems with Tyvek are:

1) Incompatibility with the tannins in redwood and cedar. I wouldn't place either of those woods in contact with it.

2) Incompatibility with the resins in OSB, which neither of us use anyway (but I would worry about the resins in the plywood glue, but I've seen no failures ---yet).

3) The flashing details have always bothered me, I see no way to adequately flash Tyvek. Even with Bill's method I see weak points in the square area, and under the right hand in the round area in his picture below. I think your plasterer is discounting the Tyvek and using Grade D to protect himself, I think he's wise.

[Bill Robinson]

Re: Flashings, Leaky Windows, House Wrap, Etc

Peter,
As long as the aluminum is "insulated/isolated from the corrosion-resistant fastener it should be OK.

I prefer truss head screws, corrosion resistant of course.

K-lath makes some.
Swan Secure and others.
Paint on the Al or maybe even a daub of caulk. Compatible of course. And if you are covering the window flange with a peel and stick don't use sealant to avoid the "C" word.

Bill R

[Peter Bush]

Re: Flashings, Leaky Windows, House Wrap, Etc

Guys,

Windows and doors are not the only sidewall penetrations in a typical home. We also have: dryer vents, bath & kitchen vents, electrical service entrance, exterior outlets, and lighting.

None of these have nailing fins, and preclude detailing in the same fashion as windows. I'd be curious as to how you're detailing some of these "trouble" spots.

Peter

[Martin Holladay]

Re: Flashings, Leaky Windows, House Wrap, Etc

Allan,
Concerning your item #8 -- "Roof sheathing has Grace Ice & Water Shield applied solid" -- do you mean that your entire roof deck is covered with Ice & Water Shield? If so, be careful. If that is your detail, you would certainly want a very generous ventilation channel under your roof sheathing. If I were you, I would sleep better at night for the next ten years if the roof didn't have such a vapor-impermeable layer. Even if you have air movement under your slates (and you should), that will not help ventilate your plywood sheathing under the rubber membrane.

[Allan Edwards]

Re: Flashings, Leaky Windows, House Wrap, Etc

Dick:

I am not that concerned about incompatibility issues with Tyvek. That’s just an intuitive, common sense position on my part, not necessarily based on any facts, however, Dupont is a Chemical Company, right? I would assume there is much laboratory and field testing of their products.

I would place any wood in contact with Tyvek without worry of resins coming in contact with it, but for other reasons I would always want an air space between wood siding and any solid surface. Same for Tyvek coming in contact with plywood, not much concern on my part.

As for my plasterer discounting Tyvek, here, we are required, by local code, to install (2) layers of grade D paper. Tyvek is an accepted substitution for grade D paper, I could probably not use that third layer of grade D paper, but for redundancy sake I am. Actually, when I think back on all of the stucco homes I’ve built, I have never had a warranty call on stucco! That’s really pretty amazing. I have had 2-3 windows that have leaked, that has prompted me to use window pans and pay closer attention to window flashings.

Peter:

I agree with you 1000%, there are countless other penetrations that should be sealed (NP-1 caulk?, Tyvek Flex Wrap).


Martin:

Are you talking just general attic ventilation? I’ve never had any issues with this, have used it on several homes, in fact my own home has had it for 4-5 years. My application is similar to their site http://www.graceathome.com/pages/dow.../GIWS-055E.pdf What are you suggesting?

I talked to my roofer, http://www.tileroofsoftexas.com/ he is not aware of any special problems with it, maybe I should speak to a rep from Grace. By the way, I also apply 30# paper over the Ice and Water Shield.

[Shavey]

Re: Flashings, Leaky Windows, House Wrap, Etc

So, to pull all this together, how would you devise a perfect system? I’m in the process of building my largest spec home ever (3 million$). It’s 3 coat stucco, metal lath, weep screeds etc. I want it “right”, don't want to be getting sued when I'm Dick's age. I have a three story home, 10,000 sq ft, 2x6 walls, 11’ first floor, 10’ second floor, 9’ third floor (we have a 35’ max height restriction).

Here’s how I’m building it, tell me what I’m doing wrong:

1). Used the best grade of material in my market: DF #2 for studs, #2 SYP for rafters (2x8), ½” CDX for exterior solid sheathing, 5'8" CDX for decking. Nailing pattern on sheathing is 4” OC @ the edges, 6” in the field.

2). We use Simpson 2.5 clips on all rafter to plate connects, 36” straps on the exterior of plywood sheathing between floors, and 12” straps on the top of rafters-rafters over the ridge.

3). I used all copper flashings, including copper eve strip. Flashings installed correctly.

4). I used Tyvek Stucco Wrap as layer #1, wrapped into window openings.

5). I used Tyvek Home Wrap over the Stucco Wrap, again, wrapped into the window openings.

6.). Stucco contractor will add one layer of grade paper on top of my (2) layers of Tyvek.

7). All exterior doors have lead coated door pans.

8). Roof sheathing has Grace Ice & Water Shield applied solid, with 30# felt over it. Roof will be slate.

At all window openings I am doing the following:

1.) Wrapped Tyvek into opening.
2.) Applied Tyvek 7” wrap (creases in corners) at the bottom window seal, turned up 6” on side.
3.) Put window pan on top of Tyvek.
4.) Added what we call window wrap on the sides of the opening, lapping over the turned up flange of the window pan.
5.) Installed the windows (have nailing fins), leaving a 1/8” gap at bottom for water to shed.
6.) Flashed the top of the window with membrane wrap.
7.) Added another 6” layer of window wrap (giving me 2) over the side flanges of the window.

My only issue is flashing the top of the window. The flashing really needs to be behind both layers of Tyvek, but I don’t want to cut the Tyvek. Right now I am leaning towards using a 9” membrane “flashing” just “attached” over the 2 layers of Tyvek. Any suggestions? I don’t want to use metal head flashing, because my windows are clad aluminum, I think the membrane will be OK. Also, in looking at it seems the nailing fin gives some water protection, although not sure it’s designed for that, I’m asking the manufacturer.

OK, shoot it down guys.

I am presently making repairs on a home covered with stucco that was built in the 1800`s....get ready for this sit down....The front corner post of this two story house is completely eaten apart top to bottom to the point where i could stick my fist thru this 6x6 post with no effort at all, the sills are also completely eaten and we are replacing those ,also sheathing boards were rotted from the second story down. We could see in behind the front porch that is leanning about a good 5 inches towards the street and the bottoms of the studs are suffering from rot also and the sill is disintegreated directly under the corner post that use to be there.My advice to you.... and this ain`t gonna be easy to take so get some asprin...lol ``Forget stucco`` because once it starts to fail the whole wall is in for big trouble and when cracks start to form in it( and yes cracks can happen even on a new structure mother nature says so)major repairs are heading in your direction. I don`t mean to be a kill joy I am merely giving you an inside observation that you may not have ever heard if i had not stumbled across your post

[HenryP]

Re: Flashings, Leaky Windows, House Wrap, Etc

a home covered with stucco that was built in the 1800`s....get ready for this sit down....``Forget stucco`` because once it starts to fail...

To Shavey:

Possibly... on a 100 + year old frame structure there are other contributing factors here?

To quote Shavey, "I don`t mean to be a kill joy I am merely giving you an inside observation that you may not have ever heard if i had not stumbled across your post".

Just an "inside observation".

[Allan Edwards]

Re: Flashings, Leaky Windows, House Wrap, Etc

Shavey:

If in the year 2125 someone is talking on a forum about the stucco on one of my homes falling off, it probably will not have an effect on me.

Allan

[Martin Holladay]

Re: Flashings, Leaky Windows, House Wrap, Etc

Dear Allan,
Here in the Northeast, most roofers use Ice & Water Shield at the eaves (generally 3 ft. wide, sometimes 6 ft. wide) and under valley metal (generally somewhat wider than the metal) as insurance against water backing up behind ice dams. Rarely do roofers install Ice & Water Shield over then entire roof deck, although I have heard of the practice.
Here's the problem: in a heating climate, you are installing a wrong-side vapor barrier. It can still work, but you must be absolutely certain that you have properly managed your interior moisture details to be sure that no condensation occurs on the underside of the roof sheathing. That means (1) a very tight air barrier at the ceiling, and, ideally, (2) a very good ventilation channel under the roof sheathing -- if it were me, on a $3 million house, I'd want the channel to be at least 1 1/2 inches high and completely clear, soffit to ridge.
The reason is that you are building an unforgiving assembly. If any condensation occurs under the roof sheathing, absolutely no drying to the exterior is possible. Believe it or not, quite a bit of drying to the exterior is possible if you have only 15 or 30 lb. felt on the roof, due to wind action and temperature differentials, through many types of roofing, including asphalt shingles, concrete tile, wood shingles, and slate.

[Allan Edwards]

Re: Flashings, Leaky Windows, House Wrap, Etc

Martin:

I’m not following you on the channel, we apply decking on the rafters, maybe you mean furring strips on the rafters? Honestly, even though we are in a relatively humid climate, condensation problems in attics do not seem to be a problem here, I don’t think I’ve ever had a warranty call on one. My own home has Ice & Water and my attic has not had any kind of moisture problems I am aware of.

I see a lot of tile roofs here installed with only 30# felt under them, I consider that a poor application myself. I like the ice and water as a fairly long term membrane covering. The last thing you want on a $75,000 roof is to have to pull it off in 10-20 years.

[Martin Holladay]

Re: Flashings, Leaky Windows, House Wrap, Etc

Allan,
I realize why we are miscommunicating; for some reason I got the impression that we were talking about cathedral ceilings. I realize now (am I right?) that your design has an uninsulated roof over an attic. Sorry for my mistake. If attic air is circulating under the roof sheathing, you should be fine.

[Allan Edwards]

Re: Flashings, Leaky Windows, House Wrap, Etc

Martin:

Yep, you guys have basements, we have attics. I would guess with a cathedral ceiling, air space would be an issue. By the way, isn’t 30lb felt now just #30 felt? Not really 30lb like days of old.

Allan

[Dick Seibert]

Re: Flashings, Leaky Windows, House Wrap, Etc

I've still go concerns about these tile (or slate) roof issues. In '76 I built two houses in a family compound, both with concrete tile roofs and attic spaces. One of them we hot-mopped under the tile, and the other we covered the plywood with 30# and interwove 30# through the tile. The house with the 30# has survived 27 years just fine, with the exception of organic material form oak leaves deteriorating the interwoven 30# in areas under oak trees, and deterioration at some of the gutter flanges which weren't sealed with Ice and Water Shield¹ (it wasn't available until '79, or at least I didn't know about it yet). Meanwhile the house that we tried to do a better job on was in bad shape, the hot-mopping was all alligatored and leaking all over the roof. I am told that the heat buildup between the tile and the hot-mopping caused the hot-mopping to deteriorate because it can't "breathe" like the 30# did on the other house.

Now I've got a church parish built 20 years ago that I also hot-mopped under the tile, and the hot-mopping is all alligatored under the tile on it. The church building does have a cathedral ceiling! http://www.fototime.com/{609FF48A-E8...9}/picture.JPG (there are continuous soffit vents but no ridge vents, and there are no recessed light fixtures) I was getting ready to remove the tile, install Bituthene, and replace the tile like I did on the other two houses, but after reading this thread I met with the roofer this morning and he is contacting both the tile manufacturer and W. R. Grace to get their recommendations and have them contact me.

I have to wonder, old Spanish tile roofs lasted about 60 years with hot-mopping under them, and I am told by a roofing expert that they aren't controlling the temperature of the hot tar like they use to, and Bituthene should work fine, I also have to wonder about flat roofs, every one I've ever built, or even seen, is hot-mopped with no air-space, or some more modern product. Am I really expected to stand out at the kettle with a thermometer and monitor the temperatures of the hot tar?

Unless I find out differently I'll have to assume that the house in the family compound failed at 27 years because the hot-moppers failed to control the temperature in their kettles, the Parish house failed at 20 years because of either failure to control temperature, and/or lack of ventilation in the cathedral ceilings. But what about hot-mopped most flat roofs? They never have ventilation, the only thing I can think of is that flat roofs are only expected to survive 20 to 25 years, while hot-mopping under tile is expected to survive 50 to 60 years.²

¹ I don't understand the difference between Bituthene, Ice & Water Shield and Vycor, all are W.R. Grace products that look the same to me, I'll be asking the Grace representative when he contacts me.

² Allan and I are both trying to do the best job we possibly can here, and are spending extra money to do a better job, but getting conflicting messages from our roofing installers and material suppliers. Having the 30# roof outlast the hot-mopped roof was a real eye opener to me.

[HenryP]

Re: Flashings, Leaky Windows, House Wrap, Etc

Hey Dick:

I want to take this opportunity to say that I find most of your posts educational and entertaining…however, when I start to see your own footnotes (like on this last post), it is beginning to scare me.

What’s next - an index and a bibliography?