Stucco Control Joints

[conarb]

I'm curious as to how many here are enforcing the residential control joints in stucco? In the past this has been ignored in single family residential construction, but apparently not anymore. Since this is controverisal here is a pretty good look at the controversy.

The International Building Code and most model building codes reference ASTM C1063, the Standard Specification for the Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster, as the lath installation specification. C1063 makes no differentiation between control and expansion joints—however, let’s consider control joints to be one-piece joints and all two- or three-piece joints, including back to back casing beads to be expansion joints. Generally, the industry uses the terms interchangeably. ASTM C1063 states, “Control joints shall be formed by using a single prefabricated member or fabricated by installing casing beads back to back with a flexible barrier membrane behind the casing beads. The separation spacing shall be not less than 1/8 inch or as required by anticipated thermal exposure range (per author and to accommodate stucco shrinkage).” It goes on to state that it has to conform to the previous section that states the following: “Lath shall not be continuous through control joints but shall be stopped and tied at each side.” The specification continues: “Control (expansion and contraction) joints shall be installed in walls to delineate areas not more than 144 square feet and to delineate areas not more than 100 square feet for all horizontal applications, that is, ceilings, curves, or angle type structures. The distance between control joints shall not exceed 18 feet in either direction or a length-to-width ratio of 2 1⁄2 to 1. A control joint shall be installed where the ceiling framing or furring changes direction.” Finally, it states, “A control joint shall be installed where an expansion joint occurs in the base exterior wall. Wall or partition height door frames shall be considered as control joints.”¹

¹ http://www.wconline.com/CDA/Archive/0d6db97b2b768010VgnVCM100000f932a8c0____

 

[peach]

Have yet to see properly applied stucco.. (and people wonder why their stucco is cracking).

 

[RJJ]

CA: This is a big issue and the code still does not address it in a total format. Control joints only provide a place for cracks to stop or start. They can cause problems as well. Now I know Stuccoman will be on this and we have talked at length regarding stucco issues. I require control joints as needed. The drainage plain is the most important factor. Spider cracks happen even within control panels.

 

[Uncle Bob]

Have not seen our Stuccoman on here in a while. I hope all is alright.

I don't remember seeing many cracking problems in the old days; when they used chicken wire.

Uncle Bob

 

[conarb]

Uncle Bob has always told us that the I Codes are supposed to be "stand-alone" codes, as I recall the ICBO saw fit in about 1968 to specifically call out weep screeds in the code, I have to wonder why they didn't specifically call out control joints at the same time instead of referencing ASTM 1063, since they go hand-in-hand?

 

[RJJ]

Yes! Carl is fine. Just haven't had any stucco issues for him.

CA: The weep screeds are a must! The expansion is a debatable issue! The problem is that the plaster indusrty has a great deal of control over what is and isn't. Like one coate stucco. Hows that work? Also we have a wide range of water barriers that don't work. Dupont junk! and Typar!

 

[Uncle Bob]

Conarb,

" how many here are enforcing the residential control joints in stucco?"

Keep in mind; that Stucco may not be a "required inspection" in all jurisdictions.

"the I Codes are supposed to be "stand-alone" codes"

That was; the International Residential Code was designed to be a "stand-alone" code.

However, I too wish the ICC would provide the standards they reference. The industry has become so big that; with all the new products that are used; they find it neccessary to reference manufacturer's and other standards.

The main problem is educating the inspectors. It's not enough in todays world to know what is in the code books; because, so much of the building materials have specialized requirements and installation instructions that are not and cannot be specifically addressed in the code books. The IRC would be 26 volumes; instead of 44 Chapters. As it is; the ICC added 198 pages to the 2009 IRC. That is a 1/3 (33%) increase; and most jurisdictions will only address a few specific changes.

It takes full time continuing education to keep up; not, just the required few hours.

I have been retired for two years now; and with all the spare time I have; still find it hard to keep up with all the new changes and product installation requirements. I also spend time on construction sites; and the sad fact is that we need more knowledgeable inspectors and Building Officials than we will ever have.

We can't win; so we must adjust; and keep on learning. The codes are only as good or bad as the inspector in the field; assuming of course the Building Official is "allowed" to enforce the codes.

Uncle Bob

 

[TimNY]

The main problem is educating the inspectors. It's not enough in todays world to know what is in the code books; because, so much of the building materials have specialized requirements and installation instructions that are not and cannot be specifically addressed in the code books. The IRC would be 26 volumes; instead of 44 Chapters. As it is; the ICC added 198 pages to the 2009 IRC. That is a 1/3 (33%) increase; and most jurisdictions will only address a few specific changes.

We had an inquiry regarding whether a permit was required to remove existing stucco and re-stucco. When I told them 'yes', conversation ensued and I explained that the weep screeds et al had to be inspected.

Permit has been applied for.

Now, to prove UB's point... There has never been any training offered on this! I know the basics, just from my own reading, but I am also painfully aware that overlooking a single detail can have catastrophic results. Training is the issue... I have never seen a course offered. In a state where the training is continuously touted as being so terrific, I have to dissent and say I have found very little of the offered course material useful.

If anybody has any links or anything that may be useful, please let me know. Frankly I have no idea where to start.

 

[RJJ]

TIM & UB the problem goes deeper then that. It is not just the code or inspectors that need education it is the contractors. Most don't know which way the cups go or even the nail pattern. When you ask them about keying in they look at you like you have three heads. Stucco problems exists all accross this country. And they will continue.

 

[TimNY]

True RJJ. As has been pointed out before, for many of these contractors *we* are the educators. I am happy to learn, but I don't see anything offered for training. You can learn a lot from manufacturers instructions, but it is unlikely you would learn everything you need to know to perform a good inspection.

(and when I did my retaining wall, I couldn't figure out which way the cups face, either!)

 

[Uncle Bob]

By the way; in-house training is good for CEUs; or at least it used to be. One way is for several inspectors to go out on an inspection with with code books and/or installation instructions, in hand (like a lath inspection). You'd be amazed at what you can learn when you put your heads together on site.

I passed chicken wire on my first lath inspection. My Building Official happened to drive by the site later that day; and I didn't make that mistake again. He made sure I knew what I was looking at the next time.

Uncle Bob

 

[conarb]

Uncle Bob:

What's wrong with "chicken wire"? I don't have the IRC but the CBC (IBC) references ASTM C 847, C 847 approves 3.2 Metal Lath , 3.3 Welded Wire Lath, and 3.4 Woven Wire Lath. it also references ASTM C 1063.

Woven Wire Lath (Illustration 4) is another product selectively used by the stucco industry. Because it resembles poultry netting it is sometimes referred to by the street names of “Chicken Wire” or “Stucco Netting.” Over the years, it’s acceptance seems to have been relegated to installations of proprietary manufactured onecoat stucco products. It is usually ordered by its dimension across its openings along with the gauge of the wire. For example 1-inchby 20-gauge.¹

It's interesting that it states: "Over the years, it’s acceptance seems to have been relegated to installations of proprietary manufactured onecoat stucco products." Here in the Bay Area, an area with 7 day framing inspections and steel frames in homes, that over 90% of stucco installations on residential structures use chicken wire, I've only used expanded metal lath on commercial work, have build multimillion dollar homes with chicken wire in the stucco. On the other had we all saw those pictures of drive-by inspections in Texas of homes stick-built with 2x4s and no steel framing, yet apparently covered with expanded metal lath, if Uncle Bob was the inspector, except for one time. On the home I have in design now I am going to be using ribbed expanded metal lath, I am doing this to avoid all sheathing so the Greenies can't make me use OSB, and also to allow my walls to breathe and dry to the outside.

¹ http://www.mnlath-plaster.com/library/documents/LathInspectionResourceManualUpdate2009.pdf

 

[JMORRISON]

Here is good resource. You can obtain guest membership to most of their technical literature if you are an inspector.

http://www.nwcb.org/publications.php?view=stucco