# DryVit vs. Vinyl Siding



## concretemasonry (Oct 10, 2006)

If you have wood framing, forget about Dryvit. It may not even be permitted. If you have steel studs or concrete masonry it can be a good product.

Dryvit is not for amateurs. Vinyl siding can be a DIY product.

Nothing is cheaper than vinyl siding period!!!!!


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## tripower (Nov 16, 2006)

concretemasonry said:


> If you have wood framing, forget about Dryvit. It may not even be permitted. If you have steel studs or concrete masonry it can be a good product.
> 
> Dryvit is not for amateurs. Vinyl siding can be a DIY product.
> 
> Nothing is cheaper than vinyl siding period!!!!!


Really? So I'm assuming the weight of the DryVit is just too much for wood framing, yes?


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## Tscarborough (Mar 31, 2006)

No, it is simply not suitable for application over wood framing. If you want that look and have a wood framed home, consider a 3 coat cementious stucco application. It is not so cheap as vinyl, but it is a better product when done right.


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## tripower (Nov 16, 2006)

Tscarborough said:


> No, it is simply not suitable for application over wood framing. If you want that look and have a wood framed home, consider a 3 coat cementious stucco application. It is not so cheap as vinyl, but it is a better product when done right.


How do you prep the walls for the stucco? I'm assuming some sort of mesh material?


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## Tscarborough (Mar 31, 2006)

If you were to strip the walls to bare studs, you would apply building paper, then metal lath, then a scratchcoat of stucco, then a browncoat, then a finish coat. Casing all edges, flashing all openings, and using expansion joints in all the right places, of course.


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## tripower (Nov 16, 2006)

Tscarborough said:


> If you were to strip the walls to bare studs, you would apply building paper, then metal lath, then a scratchcoat of stucco, then a browncoat, then a finish coat. Casing all edges, flashing all openings, and using expansion joints in all the right places, of course.


Just curious why would this be acceptable but not DryVit? The stucco and metal lath seem to me after all is said and done to be a heavier material than the DryVit (but i am of course just assuming)?


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## Tscarborough (Mar 31, 2006)

The weight is not an issue. The issue is one of water penetration/moisture extraction.


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## Zero Punch (Nov 15, 2005)

I thought the problem with dryit was installation related, not following proper installation methods, poor flashing etc?


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## concretemasonry (Oct 10, 2006)

Zero Punch -

Installation problems with Dryvit include product control and uniformity, and proper methods. Too many contractors did and still not know what they are doing and treat it like the traditional, proven stucco applications. The materials used are sensitive and uniformity is critical.

The other installation problem is relate to windows/doors/vents where a possible moisture problem is created. The Dryvit system increases the effect of any window/door installation problems or gaps anywhere in the walls. The fact that 60% of the windows installed are installed improperly does not help. Any gaps in the wall systen will funnel the air and moisture through a small area, where is can collect and cause future rot, mold and othe moisture problems.

Many of the "cute" architectural treatments at critical areas around openings were difficult to install properly and offered possible point of moisture accumulation and leakage.

Because of the problems, many places do not permit Dryvit on wood frame structures, but do permit it on masonry structures. Masonry is more forgiving than wood when it comes to moisture and it does not contain any "food" for mold. Masonry walls are far more rigid, so deflection of the walls is vitrually zero, the possible cracks/openings is drastically reduced. Also, wood frame walls usually contain fiberglass and dust, that will hold the moisture and provide a place suitable for mold growth that will not dry out.

When evaluating Dryvit homes with moisture problems, it is very easy to predict the problem areas even before taking and moisture readings.

tripower -

Dryvit is not a DIY product. It will cost more than vinyle even if you could do it. Conventional stucco would also cost more than vinyl. In fact, everything is CHEAPER than vinyl. That is one of the reasons for the dramatic increase of cultured stone to make a vinyl sided home set itself off from the other monotinous looking homes at a reasonable cost.


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## Brik (Jan 16, 2007)

yea, forget the dryvit. Class action lawsuits, required disclosure when selling in some areas. Special techniques to make it work. No long term track record when done properly, very poor track record when done not just right. Google dryvit lawsuit.

Dryvit is one brand of synthentic stucco. No synthetic stucco is a DIY job and all brands can lead to major issues if not done right.


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## clasact (Oct 21, 2006)

heres another consideration I checked into the Dryvit for my house and although it looks real nice you can not do it yourself .You must be trained and lic.through them to install it and second the cost is rather high.I decided to go with the three step accrillic stuco it cost more then siding but imo will look alot better and give the house a better seal plus I get the satisfaction of doing it myself eventhough its alot of work


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## B12345 (Apr 11, 2009)

*Dryvit question*

Hello to concretemasonry. Tell me, please, do you know if Dryvit needs to be painted or sealed after application? A friend had it installed on a 3-car garage he built. Caulking at joints/windows seems appropriate, but I wonder if the product allows any moisture infiltration that would be prevented if the Dryvit was sealed or painted. Thank you!
B12345 4/10/09
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concretemasonry said:


> Zero Punch -
> 
> Installation problems with Dryvit include product control and uniformity, and proper methods. Too many contractors did and still not know what they are doing and treat it like the traditional, proven stucco applications. The materials used are sensitive and uniformity is critical.
> 
> ...


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## Leah Frances (Jan 13, 2008)

I don't get the comparison. Dryvit v. vinyl? They're two TOTALLY different looks. Do you want a stucco look? or siding look? That should make your decision.

As to the product - ever seen a house damaged by a bad Dryvit install? I have. - on an insurance company inspection - I could push my arm through the exterior wall. 

Fist - THROUGH - wall. 

Dryvit, plywood sheathing, clear on through the cavity to the drywall - all of it rotted and damaged beyond repair. BTW, the homeowner signed off on the install, so the contractor wasn't going to pay, Dryvit (despite MILLIONS of dollars of lawsuits) wasn't going to pay (b/c it's an 'install issue'), and the HOers insurance sure as heck wasn't going to pay. The guy's house was quite literally falling down around him.


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## wildcat (Oct 24, 2008)

concretemasonry said:


> Zero Punch -
> 
> ...Masonry walls are far more rigid, so deflection of the walls is vitrually zero, the possible cracks/openings is drastically reduced...


This is not exactly true. Masonry is in fact more rigid than wood, but masonry is also less ductile than wood. Meaning that when masonry does deflect it has less of a chance of returning to its original shape/position. This is why steel reinforcement is added to masonry.

In fact the deflection criteria for masonry is much more strict than it is for wood. Typically the most restrictive deflection required for wood structural members is L/360 for floors (the span of the member in inches divided by 360), and in most cases walls are L/240 . For masonry deflection is limited to L/600. So for a 9' tall wall a masonry wall is only allowed to deflect 0.18", the same 9' wall framed with wood is allowed to deflect 0.45".

So whats the point? If you want to use a material that is easily cracked as finish on wood framing, you just need to use bigger sections (2x8 instead of a 2x6), in order to limit deflection.

My opinion is that DryVit is just not a very good product, it's extremely difficult to be consistent with. And moisture problems for wood vs. masonry is not really the concern, because it can be bad for both for different reasons. I'm not really a big fan of vinyl either.

My recommendation is that when you are looking at the construction/renovation of your homes exterior walls is that you concentrate on and extensively research how you can prevent moisture and air infiltration, and how you can maximize the R-value. Search for construction details and really read everything (brochures, specifications, etc.) that you can get from material manufactures. This will help you decide what type of exterior finish is right for you.


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## jomama45 (Nov 13, 2008)

Wildcat, your assesment may make work on paper, but when have you ever seen deflection in a masonry wall above grade? I really think the discussion here is about above grade, unless the OP is going to side under ground.


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## wildcat (Oct 24, 2008)

I've seen many above grade masonry walls where deflection had a serious negative impact. They were under reinforced, or the proper grout was not used to connect the masonry units to the reinforcement, or proper waterproofing was not used. Both of these cases lead to deflection and cracking that resulted in moisture intrusion. Moisture intrusion caused all kinds of issues like spawling, severe efflorescence, corrosion of reinforcement, etc. In most of the cases the walls were barely reinforced to take wind load, so there is no way they where going to be able to support axial load for roof or floor above as well as act as a shear wall.


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## jomama45 (Nov 13, 2008)

I still beg to differ Wildcat. Unless your talking about commercial walls that may be 30 or 40' high. I've seen a ton of residential above grade walls 8-10' high with NO re-enforcement that would outperform any wood wall when it comes to deflection. And just remember, the more load you put on a masonry wall (in perspective to width) the stronger the wall becomes.


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## wildcat (Oct 24, 2008)

jomama45 said:


> I still beg to differ Wildcat. Unless your talking about commercial walls that may be 30 or 40' high. I've seen a ton of residential above grade walls 8-10' high with NO re-enforcement that would outperform any wood wall when it comes to deflection. And just remember, the more load you put on a masonry wall (in perspective to width) the stronger the wall becomes.


Short walls too. I just looked at a 8' tall screen wall (extending about 20' past the end of the home) that was deflecting about 5". The wall is a double wythe brick masonry wall. The only reason it has not fallen is because it is now bearing on a fence post, which is about to give out.

My point was not that masonry doesn't deflect less. My point was that masonry is very prone to moisture issues just in different ways than wood. Masonry cracks easier and thus must have a bigger cross section to prevent the deflection, because if masonry deflects even a little tiny bit, it will crack.

Also adding more axial load to masonry only improves its strength if the axial load is through the centroid of the wall section. If it is not through the centroid then the eccentricity of the load will actually induce more deflection into the wall.


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## concretemasonry (Oct 10, 2006)

Way off base on the purpose of reinforcement in a masonry wall. The steel reinforcement is there to increase the tensile strength of the wall and does little to increase the stiffness. Even plain grout does as much good as reinforcement. Some rebar is only used for continuity, as in a bond beam that is normally not a structural element.

A noted and respected engineer and code author, Jim Amrhein, always said put as little as possible into the wall so you know better what you have. - The Brazilian engineers have followed this thinking when they designed hundreds of 15-22 story 6" masonry loadbearing apartments using a partial grouting and had some walls that had no structural reinforcement except for the "continuity" reinforcement around openings and a bond beam/slab.

Dick

If you make those simplistic assumptions to ease the calculations, like many of us professional structural engineers do, you can fall into the "idealistic" trap and forget the real mechanics of the wall during performance. These assumptions always get in the way of accuracy and even creep into the codes. That is why we wrote the ACI 530 code to provide for several different methods of design (Empirical, Allowable Stress, Strength Design and Prestressed).

All codes have deflection requirements, but as you see the deflections for masonry are far less than lightweight construction (wood, steel stud). It is ironic that the brick veneer on a lightweight wall is far stiffer then the back-up wall. While investigating the damage from the Northridge earthquake many years ago, I saw many structures that had the interior walls destroyed because of internal loading and connections, while the exterior veener was still standing around the pile of rubble. Naturally, everything was demolished during the rebuilding. This was near the dam where the accelerations were very unusual.

Steel reinforcement does have its place if the engineers know how to use it. I saw some 24' wall panels (6" and 8" block) that were tested in flexure. They reached a deflection of 3 times the theorhetical amount and recovered without a crack. - One panel was cut to a narrower width so it could be used as a diving board


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## wildcat (Oct 24, 2008)

Dick,

I clearly stated that reinforcement is added to masonry to increase its ductility. Ensuring ductility in a masonry design is a balancing act between the capacity of compression region and the capacity of the tension region.

Grout is not a substitute for steel reinforcement in no way. Grout and concrete have no where near the tensile capacity of of steel. There are many cases where the tensile capacity of the masonry and grout assembly are sufficient and reinforcement is not required for bending or shear. In many cases the extremely heavy weight of this type of assembly helps increase the bending capacity of a wall because the weight can hold the tension face together. This heavy assembly without reinforcement will not work in high seismic areas.



> All codes have deflection requirements, but as you see the deflections for masonry are far less than lightweight construction (wood, steel stud). It is ironic that the brick veneer on a lightweight wall is far stiffer then the back-up wall. While investigating the damage from the Northridge earthquake many years ago, I saw many structures that had the interior walls destroyed because of internal loading and connections, while the exterior veener was still standing around the pile of rubble. Naturally, everything was demolished during the rebuilding. This was near the dam where the accelerations were very unusual.


I've stated more than once that masonry has a bigger cross section that that of wood, resulting in the lower deflection. For example an 8" cmu has a great moment of interia that a 2x8 wood member does (also the modulus of eleasticity is much higher in steel and wood than it is for masonry). The higher moment of inertia is the result of the lower deflection. Again masonry is not as ductile as wood or steel, thus the need for the larger cross section and moment of inertia.

I will also point out that heavier, more rigid, and less ductile structural elelments will attract seismic forces much more so than a member that is light and ductile. Proper amounts and placement are extrememly critical in masonry design for seismic.

Another thing of note is that if a masonry wall defelcted three times the allowable code limit, then it for sure cracked. If it deflected that much then the moment on the masonry was great than the cracking moment for the section. This is why the reinforcment was needed, because without it the wall would have been destroyed as it would not be ductile enough to return to its original shape. I can asure that the tension face cracked the masonry but did not yield the steel.


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## alexandersh (May 22, 2009)

*Dryvit experiation date?*

We purchased dryvit from a friend that wanted to change colors and so got it at a great deal. We are looking for a professional to install. One person we talked to said it is no good if over one year old. What we purchased is about 1 1/2 years old. Is this true? Do you have any recommendations?


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## Bob Mariani (Dec 1, 2008)

I had a client that was going to use dryvit on a 13,000 sq/ft home. But after talking to neighbors found complaints that it whistled during periods of high winds. Changed to stone and brick siding. Dryvit needs a good drain plain behind it to assure no moisture problems affecting a wood framed house. This step alone is more than vinyl siding.


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## James Gentry (Mar 27, 2010)

Notice who is bad mouthing Dryvit, brick and concrete masons. Do you think that they are a bit biased? Dryvit, STO, Synergy, Parex and a few other materials are FAR BETTER than the other sidings if done right. You nailed it when you said that the problem was application. What most don't mention is that the application problem was more than just not following the proper installation specs.It was also what it was being applied over. As far as class action suits, ask these guys how many were won? Stucco when done correctly offers far better insulation and aesthetic possibilities than the other sidings. Hey you brick guys, tell him some stories about removing damaged brick walls and finding out that the brick was the only thing holding up the house due to wood rot.


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## kwikfishron (Mar 11, 2010)

Well, Dryvit sure doesn't work on the Coast. I've torn it off a couple houses due to constant leak issues. What a MESS that was.


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## tpolk (Nov 7, 2009)

any exterior siding has potential for badness


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## Leah Frances (Jan 13, 2008)

James Gentry said:


> Notice who is bad mouthing Dryvit, brick and concrete masons. Do you think that they are a bit biased? Dryvit, STO, Synergy, Parex and a few other materials are FAR BETTER than the other sidings if done right. You nailed it when you said that the problem was application. What most don't mention is that the application problem was more than just not following the proper installation specs.It was also what it was being applied over. As far as class action suits, ask these guys how many were won? Stucco when done correctly offers far better insulation and aesthetic possibilities than the other sidings. Hey you brick guys, tell him some stories about removing damaged brick walls and finding out that the brick was the only thing holding up the house due to wood rot.


I'll bad mouth dryvit and the like and I am neither a bricklayer or a mason. I am a retired attorney and I worked on millions of dollars of cases of dryvit gone bad. 
- Yes, it was almost always because of installation defects or improper modification. Seems like no one knows how to do this right. 
- No, it was not at the coast, it was central Oregon. 
- and Yes, the homeowner ALWAYS gets SCREWED.


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