# Moisture everywhere i go



## jkfox624 (Jun 20, 2009)

Why is it everytime i pull vinyl siding off the nails are always rusted to hell? Its not like its around a window it could be up under the eves with no signs of leaks. Anytime i pull a piece of insulation out of a wall in a newer job theres signs of moisture behind it. 

The small job we just did, cut a new opening in for a man door the osb was bowed out atleast 1/2' between the 16" wall studs. This job was taped drywall, r 13 kraft, stapled to the face of the studs, OSB, housewrap and vinyl siding. This is becoming a very common theme in every mod we do in newer construction. Is it an issue with the building practices? Houses not breathing right? With what ive been seeing the last 3 years or so it makes me think theres gonna be alot of issues in the coming years.


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## Tom Struble (Mar 2, 2007)

house have always had these problems,sure some more than others but there have always been moisture issues


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## RobertCDF (Aug 18, 2005)

Embrace it, it's called job security. When everyone starts building ICF houses is when you need to worry.


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## jkfox624 (Jun 20, 2009)

Tom Struble said:


> house have always had these problems,sure some more than others but there have always been moisture issues


We made a window smaller on the front side which was original nothing wrong at all. But of course it had no insulation.


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## Tom Struble (Mar 2, 2007)

and...? i don't get your point


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## Tinstaafl (Jan 6, 2008)

Tom, I think he's saying that area had no sign of moisture problems.

It's true though, I see far more moisture issues with newer houses than the leaky 100 year old ones. Well, the ones that are still standing.


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## jkfox624 (Jun 20, 2009)

Tinstaafl said:


> Tom, I think he's saying that area had no sign of moisture problems.
> 
> It's true though, I see far more moisture issues with newer houses than the leaky 100 year old ones. Well, the ones that are still standing.


Yeah i can pull clapboards off 100 year old house and nails are fine. I peel vinyl off a 10 year old house and the nails are rusting to the point some are like wires. Are insulating practices not allowing the structures to breathe? I'm not looking for an argument but if the way things are being done isnt gonna work longterm its partly our job to find an answer.

Is it because insulation is packed tight to the sheathing? Is it moisture escaping the house and not being able to get to the outside? Is it the pressure differences in the house sucking moisture behind the vinyl and wicking in around the nail holes?

Or should i just not worry about it and figure thats the way it is and in 20 years get to build it all again.


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## Tinstaafl (Jan 6, 2008)

jkfox624 said:


> Is it because insulation is packed tight to the sheathing? Is it moisture escaping the house and not being able to get to the outside? Is it the pressure differences in the house sucking moisture behind the vinyl and wicking in around the nail holes?


If I was a rocket surgeon I'd fill a blackboard with formulas and tell you all the answers. :jester:

I suspect that part of the issue is the widespread use of aluminum and vinyl siding. I've never sat down to codify my thoughts on the matter, but I've seen plenty of evidence that neither is totally rainproof. I also think there can be condensation involved.

The heck of it is, even if you figure out the perfect answer, codes probably won't let you use it.


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## Tom Struble (Mar 2, 2007)

i would bet we are pulling alot more stuff off of more modern stuff because that what is most still around ..no?the stuff we see thats 100 years old is mostlikely will last..idk 300 say but we don't work on many of them cause well many many have either burned down or rotten away


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## CompleteW&D (May 28, 2011)

Tinstaafl said:


> If I was a rocket surgeon I'd fill a blackboard with formulas and tell you all the answers. :jester:
> 
> *I suspect that part of the issue is the widespread use of aluminum and vinyl siding.* I've never sat down to codify my thoughts on the matter, but I've seen plenty of evidence that neither is totally rainproof. I also think there can be condensation involved.
> 
> The heck of it is, even if you figure out the perfect answer, codes probably won't let you use it.


You know Tin.... I don't think the problem is just aluminum or vinyl either. We pulled ~8-10 year old fiber cement off of one side of a house to change an opening from a large double window and convert the opening into a French door, and the fiber cement was literally black on the back side just covered in mold.

I don't think it was as simple as a window leak since the mold went up above the top of the window opening. It went about six feet on either side of it where it was really bad. We couldn't find any evidence of a roof leak, soffits were in good shape, gutters seemed to drain properly, fascia boards above the moldy area were fine. 

The area was just off the kitchen, but no bathroom near by and no second story above. Nothing showed signs of being wet (sheeting, insulation, studs, top and bottom plates etc.) or had any evidence of large amounts of moisture in the past. In the end, we just had to say.... we didn't know where it came from. We re-sheeted, new house wrap, installed new fiber cement and called it a day. 

I sure would like to go back in a few years and see if it comes back.


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## Tinstaafl (Jan 6, 2008)

CompleteW&D said:


> I don't think it was as simple as a window leak since the mold went up above the top of the window opening. It went about six feet on either side of it where it was really bad.


Maybe not a leak per se, but a side effect of the "temperature leak" all windows and doors have? I'm not sure just what the mechanics would be, but we've all seen that even well sealed penetrations tend to be where you find such problems.


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## CompleteW&D (May 28, 2011)

Tinstaafl said:


> Maybe not a leak per se, but a side effect of the "temperature leak" all windows and doors have? I'm not sure just what the mechanics would be, but we've all seen that even well sealed penetrations tend to be where you find such problems.


Possibly.... but we were replacing older aluminum windows. When they did the siding, (not us), they seemed to do everything right. Even to the point of using 6" Vycor around the existing windows. 

With them being aluminum, I could see where sealing up all around that opening might just cause them to sweat more I suppose. But nearly SIX feet either side? Thinking out loud, I guess it could have wicked that far over time, but DANG this stuff was as black as black could be.

But, maybe you're right.... sealing up that opening maybe could have done it. I'm really more concerned that mold even took to the fiber cement at all. It tells me it was full of organics for that mold to feed on.

Glad I didn't fall in love with the stuff like a lot of folks did. If there is a ton of mold out there on the back of older fiber cement.... :no:


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## Tinstaafl (Jan 6, 2008)

Oh heck yeah, aluminum sweats like a sonofagun. I've managed to avoid FC--it's not popular around here.

I don't think this is off topic at all. :thumbsup:


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## Tom Struble (Mar 2, 2007)

osb takes too long to dry,you have condensation coming from the inside,condensation forming on the outside,poor venting,ice dams,clogged gutters..ad infinitum 

rusty nail heads under vinyl don't bother me,water gets under all siding
wood/fc/masonry...

plus wood is hygroscopic and it's moisture content will fluctuate depending on humidity

i believe that moisture percent is by weight so even if you figured exterior wood at a 10 percent moisture content that's 10 lbs of water for every 100 lbs of wood...that's a lot of water:blink:


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## Tinstaafl (Jan 6, 2008)

So are you blaming OSB?

As for wood being hygroscopic and 10% moisture content etc, how does that explain the houses with nails that _aren't_ rusted six ways from Sunday?


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## jkfox624 (Jun 20, 2009)

CompleteW&D said:


> You know Tin.... I don't think the problem is just aluminum or vinyl either. We pulled ~8-10 year old fiber cement off of one side of a house to change an opening from a large double window and convert the opening into a French door, and the fiber cement was literally black on the back side just covered in mold.
> 
> I don't think it was as simple as a window leak since the mold went up above the top of the window opening. It went about six feet on either side of it where it was really bad. We couldn't find any evidence of a roof leak, soffits were in good shape, gutters seemed to drain properly, fascia boards above the moldy area were fine.
> 
> ...


2 years ago a similar situation. Adding a mudroom to a modular home. Pull some siding found rot around a window. Fair enough no flashing. Pulled siding down the wall and the whole side of the house the osb was gone. They stapled the vinyl on and when you pulled a staple a hockey pucked sized piece of rotted osb came with it. House wrap was dripping wet everywhere but yet the osb showed no real signs of taking on water except a small area around a window.

The house we were working on this week white siding and it was full of mold in the clip even up under the soffit. Why is water lying in there that high?


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## fjn (Aug 17, 2011)

*water*

That would be a great question to pose to Joe Lstiburek at BUILDING SCIENCE CORP.


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## Tom Struble (Mar 2, 2007)

Tinstaafl said:


> So are you blaming OSB?
> 
> As for wood being hygroscopic and 10% moisture content etc, how does that explain the houses with nails that _aren't_ rusted six ways from Sunday?


are you saying there's no moisture in wood?

my point being there is alot of available moisture sources


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## jkfox624 (Jun 20, 2009)

Tom Struble said:


> are you saying there's no moisture in wood?
> 
> my point being there is alot of available moisture sources


I guess my feeling is its getting in but not back out. Theres alot of old houses here, more homes 60+ years old than there is 10 years old but it seems im always finding moisture issues on anything newer we open up. Maybe its because the older growth wood handles moisture better than OSB and farm grown pine. Maybe its because they have no insulation and the air exchange is super high.


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## Tinstaafl (Jan 6, 2008)

Tom Struble said:


> are you saying there's no moisture in wood?
> 
> my point being there is alot of available moisture sources


Absolutely not. Obviously there's no way for wood to be bone-dry in the real world.

Granted that there are many moisture sources, what we need to be addressing is how our practices handle protection from/disposal of that moisture. What are the key differences between today's building practices and those evident in the older houses that show little sign of decay?


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## VinylHanger (Jul 14, 2011)

I think that rainscreens will help a lot once they are the norm. It gives FC a chance to air out. This is what I find in most of the old houses I work on. Lots of 80-120 year old houses around here.

The one I have been trying to get painted was built in 1904. Old growth Doug Fir lap siding. It had a failed paint job from 20 some odd years ago when I started. Not a spec of rot on the structure, not even on the window sashes. Same pulling shakes from the old mill houses around here. Lots of flies, but good tar paper and no rot.

The only rot I have found is one piece of 8 inch long 3/4 round and a sheet of plywood skirt. Actually the only real rot is an original window in the bathroom. I have avoided messing with it until last. It looks like steam has been it's downfall as it has a couple of broken panes that need fixed.

Not sure what the solution is, but with no modern practices, this house and many of the ones I've dealt with are usually in great shape. It is usually when a modern door or window is installed, that I see the problems. Dry rot around thresholds and window sills.

I think it is letting the air flow in and around that does the trick. The last 1970's house I reinstalled windows in had absolutely no caulk between the osb and the windows and trim. They weren't exactly cut tight either. Not a spec of rot. Yet, I've seen where they are caulked to death and after I pull the frames, I find all sorts of rot. So it isn't just the older houses.

I do think that OSB may be a bad idea though. But try and get someone to pony up for quality plywood when they won't ever see it, and it is a non-starter.

All in the name of saving power. Back when all the houses had wood/coal/oil heat, you would just stoke the fire to ward off any drafts. Now you can't afford to do that, or we are told that is a bad thing, so we seal them up.


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## GRB (Feb 23, 2009)

Tinstaafl said:


> Absolutely not. Obviously there's no way for wood to be bone-dry in the real world.
> 
> Granted that there are many moisture sources, what we need to be addressing is how our practices handle protection from/disposal of that moisture. What are the key differences between today's building practices and those evident in the older houses that show little sign of decay?


A couple immediate differences...

1) As Vinyl Hanger pointed out, old house were built with old growth lumber. This stuff is practically bulletproof, no matter what species, though some of course fare better than others. 
The growth rings are so close together they're sometimes hard to distinguish. This means there's quite a bit of heart wood, which is far more durable than sap wood. The reason for this is the trees from which the lumber came grew in dense forests, which slowed their growth. 

Today's lumber is generally plantation grown, where engineers & scientists have figured out how to grow trees quickly. The upshot is that there's a large amount of sap wood - the least desirable part of the tree & the part that's most susceptible to rot & decay. 

2) Houses did leak years ago. But the water or moisture that leaked in was dried through convective currents - if water was leaking in, so was air. The drying also occurred thanks to the way houses were heated. As has been pointed out, there was usually no insulation in them, so warm, dry air from the interior flowed freely to the exterior (contributing to the convective currents). 

3) We generate a lot more moisture in today's houses than our relatives ever did. Most of us take at least one shower a day (with the possible exception of Struble, who views this as a monthly chore). This moisture as well as moisture associated with cooking, doing laundry, etc. has to make its way outside, but builders often do a poor job of managing it. 

4) Yesterday's builders & architects paid more attention to detail. If you look at most old wood buildings, they were designed to shed water. They usually had generous eaves (or at least some eave detail), water tables, flared siding details at the foundation, above 1st floor windows, etc. 

It's kind of fun to study old buildings & try to pinpoint all the water shedding details, because they're not always obvious. But we've done away with many of these details for the sake of "economy". The fact is that our buildings of today need these & more water management details because of the way we build & the products we use. Omitting these details actually costs more in the long run & leads to shorter life cycles of buildings. 

5) Old wood framed houses essentially had rainscreens. They weren't designed with them in mind, but that's what they ended up with. The stud bays were a source of convective currents - especially in balloon framed buildings, where studs ran from sill to rafter. These convective currents permitted the sheathing & the back side of the siding & trim to dry after they got wet. 

Modern rainscreens use the lessons learned by studying old buildings, but move the convective currents outside the envelope. I agree with those who have said they're likely one of the answers to the problems we're seeing with moisture & modern building practices. For more answers, study old buildings - the guys who designed & built left us a lot of lessons we can learn from.


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## Tom Struble (Mar 2, 2007)




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## Handyman3970 (Nov 21, 2010)

Look what happened to brick built homes when we started insulating them. Brick started spalling and falling off the outside because the heat was no longer getting through to push the moisture out. 
Brick chimneys are literally disintegrating after removing the good heat of old and now pumping cooler exhaust from efficient furnaces. Or not using them at all. 
I agree with GRB above and wonder how many problems we are creating by being increasingly more airtight.


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## GRB (Feb 23, 2009)

Tom Struble said:


>


:smartass:


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## Tom Struble (Mar 2, 2007)

being not ''air tight'' is not the answer,as squeaky clean up there observes if water leaks in so does air,which makes the reverse also true


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## GRB (Feb 23, 2009)

Handyman3970 said:


> Look what happened to brick built homes when we started insulating them. Brick started spalling and falling off the outside because the heat was no longer getting through to push the moisture out.
> Brick chimneys are literally disintegrating after removing the good heat of old and now pumping cooler exhaust from efficient furnaces. Or not using them at all.
> I agree with GRB above and wonder how many problems we are creating by being increasingly more airtight.


Your point about brick & masonry is well taken. Several years ago we had our old furnace that vented into a chimney replaced with a high efficiency direct vent model. Now the only thing vented into the chimney is a hot water heater. The result has been the chimney has started decaying because of moisture issues. I think I'm just going to demolish it all together & install a tankless HW heater.


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## hdavis (Feb 14, 2012)

Tom Struble said:


> being not ''air tight'' is not the answer,as squeaky clean up there observes if water leaks in so does air,which makes the reverse also true


Ventilation is the answer, along with a bunch of other details. In terms of air leaks on old houses, the old windows let in plenty of air, even when tightened up, but they don't leak water in. From a whole house perspective, sills and cellar doors weren't air sealed. You get plenty of airflow from the basement up and out the top without having water get in. There are a ton of other details as well which all help. I think one of the keys that people sometimes forget can be seen on some of the old sheet metal dutchmen used to reinforce a window sash joint that deteriorated. These old dutchmen were always put on the inside. The sash didn't see much water from the inside, so being able to dry to the inside after getting wet on the inside wasn't such a problem. All kinds of modern building practices do the reverse - assume the water isn't going to get in, and prevent drying to the outside.

As for old / new lumber and heartwood use, heartwood only was used in key areas, not everywhere. If you go back to the complaints from ~1900, the quality of the "modern" lumber was being berated because trees felled in the winter when the sap was down gave the superior lumber (stonger, less sugar, etc) but due to demand trees were being felled year round. River drives and ponding of the logs at the saw mill also would decrease sugar content, and make some other changes to the wood cell structure. I think a bigger issue is modern primers vs old ones. The old ones were runny, slow drying oil base, had little pigment and penetrated pretty deeply. Even with complete paint failure, the primer is sitting there protecting the wood. In shaded areas on the north side of building I sometimes come across the original primer still doing it's job protecting the wood, but after 100+ years it's so hard nothing will stick to it reliably.


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## GRB (Feb 23, 2009)

I'm going to disagree re. the heartwood issue. The point I was trying to make was that most sawyers way back when didn't necessarily distinguish how the logs were cut. The wood was what it was - it was dense & by & large very durable. 

When a piece of old growth lumber is placed next to a piece of recently harvested plantation lumber, the growth ring example is very compelling. 

I've seen plenty of old buildings with little if any finish on the exteriors & while the wood is worn & weather beaten, it's not necessarily rotting. That's in stark contrast to much of today's material (particularly Radiata pine) that sometimes fails even with a finish on it in exterior applications.

Edit: If anyone wants to take this a step further, take a piece of end grain old growth material & place a few drops of water on it, then do the same with newer stock. The water will often bead up on the old stuff, yet the new wood usually absorbs it quickly.


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## hdavis (Feb 14, 2012)

Handyman3970 said:


> Look what happened to brick built homes when we started insulating them. Brick started spalling and falling off the outside because the heat was no longer getting through to push the moisture out.
> Brick chimneys are literally disintegrating after removing the good heat of old and now pumping cooler exhaust from efficient furnaces. Or not using them at all.
> I agree with GRB above and wonder how many problems we are creating by being increasingly more airtight.


Having to put in a metal liner into an old chimney makes this worse, as well. The problem with making things closer to airtight and insulated is it frequently isn't done right, IMHO. Old houses could dry to the inside and the outside, so they could tolerate relatively high moisture loads, and they were drafty to boot. I think a rain screen design is just one element to be able to have an efficient airtight building, but there is a lot more to it.


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## Tom Struble (Mar 2, 2007)

where am i going to get old wood to wet?:blink:


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## hdavis (Feb 14, 2012)

GRB said:


> I'm going to disagree re. the heartwood issue. The point I was trying to make was that most sawyers way back when didn't necessarily distinguish how the logs were cut. The wood was what it was - it was dense & by & large very durable.
> 
> When a piece of old growth lumber is placed next to a piece of recently harvested plantation lumber, the growth ring example is very compelling.
> 
> ...


Sawyers didn't distinguish how they were cut - the carpenters selected the lumber from the pile for their particular use. Yes, denser old growth doesn't absorb water as quickly. On the other hand, I was looking at a painted fence made with PT 2X4 backers and 1X3 untreated boards with 1X4 untreated caprail. This fence probably had an actual useful lifespan of 45 years (stopped painting it about 15 years ago). None of it was old growth or heart wood.

In the end, I think things last or don't last due to a bunch of little things all added together. The beauty of the old penetrating primers is they penetrated a lot more in the less dense ares than the more dense areas, so the areas that needed the most protection got it.


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## Tom Struble (Mar 2, 2007)

ventilation is not the only answer, adequate levels of insulation [with apparently a certain amount outside the wall cavity] are needed to prevent condensation in the wall cavity

and if windows are leaking air,water is most certainly going along for the ride


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## GRB (Feb 23, 2009)

Tom Struble said:


> where am i going to get old wood to wet?:blink:


Never has a nickname been more appropriate - Strublemaker. :laughing:


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## Tom Struble (Mar 2, 2007)

i'm simply a misunderstood and under appreciated resource around here:shifty:


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## GRB (Feb 23, 2009)

Spell check can help with that.


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## superseal (Feb 4, 2009)

I've made pretty busy work of fixing the mulch mansions around our way. You can hear them rotting if you listen closely.

Funny thing is... the builders are viewed top notch and win all kinds of local awards 

Soon as I figure out that one...:whistling


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## hdavis (Feb 14, 2012)

Tom Struble said:


> ventilation is not the only answer, adequate levels of insulation [with apparently a certain amount outside the wall cavity] are needed to prevent condensation in the wall cavity
> 
> and if windows are leaking air,water is most certainly going along for the ride


I'm not trying to convince anyone. The answers to some of these problems are even found in chicken coop building discussions.


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## Tom Struble (Mar 2, 2007)

what does that mean?


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## Tom Struble (Mar 2, 2007)

you know air has moisture in it..right?you know what dew point is..?right?

sorry for all the questions but im not a chicken coop specialist like yall:whistling


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