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LP siding WRB/ Flashing requirements?


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I just finished inspecting a house built in 2000. The house has LP lap on the front and panel on the sides and rear. I was able to peel back a piece of the lap at a window (just above roof to wall flashing). I could tell that there was no flashing, just felt paper (WRB) butted up against the windows.

The panel siding was installed at the sides and back. There are water droplet stains at the head/ top area of the slider door, likely indicating leakage from the exterior.

These 2 issues got me curious.........

When did flashing become required at windows?

When did it become a requirement to install a WRB behind LP panel siding?

Also, this LP was in pristine condition with absolutely no swelling or problems whatsoever. It was meticulously maintained, and the owner hand painted it with 3 coats of paint about 2 years ago. It's pretty impressive how well a good paint job will protect this stuff. I haven't figured out whether this is first or second generation LP yet though............

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Thanks Robert. It looks like siding installed 1998 and before was affected by the recall. I just hope this siding wasn't stored somewhere and installed later. It's just very odd to see LP lap installed on homes after the 90's. I think most installers were scared of the stuff by then.

The only issue with the paint job was that they did not paint the dripedges (roof line and foundation level)-- they will now.

I am amazed by how well they sealed the siding. I could barely find the vertical joints between sections, could hardly see where nails had been installed, etc.

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When did flashing become required at windows?

When did it become a requirement to install a WRB behind LP panel siding?

I have installation instructions for L-P siding that go back to April of 1996.

Lap siding

Nailable sheathing installation

A continuous positive vapor barrier must be installed on the inside of conditioned exterior walls.

Direct-to-stud installation

Unsheathed walls require a weather resistant barrier on the exterior side of the wall (15lb. felt, soin coated paper, or a house wrap material approved by local codes.)

Item #9 states

A 3/16" gap is required where siding ends at the trim around doors, window, and other openings.

Install sloped, noncorrosive flashing behind siding and over horizontal trim and at windows and door locations. (Flashing needs to be sloped to drain water away from the siding.)

Panel Siding

Item #2 states:

A continuous positive vapor barrier must be installed on the inside of conditioned exterior walls.

Item #8 states:

A 1/8" gap for expansion is required where siding ends at the trim around doors, window, and other openings.

Install sloped, noncorrosive flashing behind panels and over trim and at windows and doors. (Use sloped flashing to prevent water from collecting at the back of the panel.)

ONE TEAM - ONE FIGHT!!!

Mike

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I just finished inspecting a house built in 2000. The house has LP lap on the front and panel on the sides and rear. I was able to peel back a piece of the lap at a window (just above roof to wall flashing). I could tell that there was no flashing, just felt paper (WRB) butted up against the windows.

The panel siding was installed at the sides and back. There are water droplet stains at the head/ top area of the slider door, likely indicating leakage from the exterior.

These 2 issues got me curious.........

When did flashing become required at windows?

A long time ago. From the 1979 CABO, R-503.8, "Approved corrosion-resistive flashing shall be provided at the top and sides of all exterior window and door openings in such manner as to be leakproof. . . "

When did it become a requirement to install a WRB behind LP panel siding?

Not till April 1, 2008.

Also, this LP was in pristine condition with absolutely no swelling or problems whatsoever. It was meticulously maintained, and the owner hand painted it with 3 coats of paint about 2 years ago. It's pretty impressive how well a good paint job will protect this stuff. I haven't figured out whether this is first or second generation LP yet though............

There are more than two generations of LP siding. The first product, Inner Seal Siding, introduced in the late '80s was little more than strips of OSB embossed with a paper coating on the front. It failed miserably. All you had to do was spit on it and it would swell. You can recognize that earliest product by the square drip edges on the lap siding version.

The first revision to the product was to put a bevel on the drip edges of the lap siding. It did very little to help anything, the stuff kept swelling and rotting and growing mushrooms. You can recognize this version by the bevelled edge and the bare OSB back.

The next revision was to keep the bevel and add a resin coating to the back of the product. You can tell this stuff by looking at the back of it. The resin makes it look sort of brownish green -- kind of like a dark olive drab color. It kept failing. This one is easy to spot if you can see the backside. Both the lap and panel versions have an olive drab resin coating covering the back side.

Then in 1996 & 1997, someone at LP got religion and they revamped the whole recipe for the product. They kept the bevelled edge, they got rid of the resin backing, they increased the content of water repellent compounds (I've heard them called waxes, but I'm not sure) they added borate to the mixture to fend off fungi, and, very important, they improved their quality control program. Then, because they realized that no one was painting the drip edges properly, they painted them at the factory. At this point, the name "Inner Seal Siding" was synonomous with crap so they renamed the product as well. They called it Smart Lap and Smart Panel siding. You can recognize this stuff because it has no olive drab resin on the back side of either the panels or the lap pieces and the lap pieces have bevelled edges. Both the lap siding and the panel siding come with pre-painted drip edges. The Smart sidings came out in '97 and, LP says, by January 1 of 1998, they had pulled all Inner Seal siding from all of the lumberyards that sold the product.

The post 1998 stuff seems to be a pretty good product. I have yet to see any wholesale failure of it.

- Jim Katen, Oregon

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Wow,

Thanks for the info. / education guy's.

When I started doing inspections I ran into LP daily. Now, it is pretty rare to see LP lap (haven't seen mushrooms in a while now). This is the first place that I've inspected this year that has had LP lap, at least that I can remember.

My assumption is that the contractor only ran the WRB over the top/ head of the window and over the sides of the nail flange. The bottom nail flange overlapped the roof to wall flashing where I was able to check for flashing. Would the WRB qualify as flashing back in 2000?

There was no trim, so no head flashings/ GSM was used anywhere. Also, the panel siding was just butted directly to the window and door frames with no trim/ flashing as is the common installation. As soon as the caulk fails, water will seep into the wall if there is no WRB behind the panels, as is likely the case.

Here is a link to Siding Solutions web page that shows how to ID different kinds of siding: http://sidingsolutions.com/pages/sidingid.htm

Maybe I should re- take the class that these guy's teach. I've lost their book, and it's been so many years that I've obviously forgotten a lot of the info.

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When did flashing become required at windows?

A long time ago. From the 1979 CABO, R-503.8, "Approved corrosion-resistive flashing shall be provided at the top and sides of all exterior window and door openings in such manner as to be leakproof. . . "

Ya, but the problem came when they started allowing "self flashing" windows to suffice, and stopped using head flashings.

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When did flashing become required at windows?

A long time ago. From the 1979 CABO, R-503.8, "Approved corrosion-resistive flashing shall be provided at the top and sides of all exterior window and door openings in such manner as to be leakproof. . . "

Ya, but the problem came when they started allowing "self flashing" windows to suffice, and stopped using head flashings.

Except that no window manufacturer every "allowed" window nailing fins to suffice and no competent trainer ever endorsed the idea. Who knows who started it; but somewhere there was a fellow that decided that, with a little caulk, the nailing fin would keep out water and he could skip the flashings. Then he taught his "technique" to someone else, who taught it to someone else, who taught it to someone else, who......

The code required flashings in addition to the windows and didn't say anything about self-flashing windows because there never has been such a thing.

Self-adhering bituthene flashings weren't really an innovation. Some guy was probably standing around watching someone put Grace Ice and Water Shield on a roof and thought, "Wow, that'd work a whole lot better than cutting those heavy felt splines." He just substituted a different material for a tried and true window flashing technique. Then as time went by, someone, maybe a cousin of the same dildo that decided that the nailing fins were flashings, decided to start leaving out the head flashings and started teaching that to his workers, who taught it to other workers, who taught it to other workers.

The ultimate dumbing down when they figured out that they could save an extra $2 per window by eliminating the top piece of bituthene by simply overlapping the top flange of the window and the two self-adhered side splines with building paper and then apply a bead of caulk around the perimeter of the window. Apparently, nobody ever pointed out to most of these ijits that wind pushes water as much as 4 inches up behind siding so the water draining down the paper and hitting the tops of windows wants to push behind the paper anyway.

The construction business lost its soul when carpenters no longer insisted on a structured system of apprentices who learned it all top to bottom as site roustabouts and helpers, became journeymen, worked as journeymen for years and later became master carpenters.

Now it's a trade populated by glorified do-it-yourselfers with MBA's or construction management degrees who hire the cheapest labor they can find, teach those laborers to do a very limited number of tasks and nothing else - and not well - and call themselves "builders."

End of my rant-o-the-day.

ONE TEAM - ONE FIGHT!!!

Mike

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Mike,

The code required flashings in addition to the windows and didn't say anything about self-flashing windows because there never has been such a thing.

The building code did say something about self- flashing windows for a while (R703.8 in the 2003 IRC), for some reason. I am not aware of any window manufacturer that did (I think that's what you meant).

Apparently, nobody ever pointed out to most of these ijits that wind pushes water as much as 4 inches up behind siding so the water draining down the paper and hitting the tops of windows wants to push behind the paper anyway.

I can't seem to find the study, but I remember reading one that said water could run up a wall several feet (I think it was ten) when driven by wind..........

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