Does anyone have a recommendation for products to use in a masonry cavity to maintain drainage. We have some limited conditions where we cannot maintain recommended cavity size, so I want to use a composite or “spaghetti” product to keep them clear. This would be a continuous product, not just at the flashing. I’ve found three so far: Keene, Driwall; Archovations, CavClear; and Sandell, Rainscreen.
I think one could probably use a drainage composite intended for waterproofing. In fact, I did this more than 15 years ago in a second story addition that had to match the first floor. But, I’d like to use a product where the manufacturer says “Yep, you can use it there.”
Short of calling all the waterproofing accessories folks, I thought someone on this board might have an idea.
York Mfg. makes flash-vent which is a copper flashing laminated to a thin drainage/weep material which is installed under the facing. No need for weep holes.
Mortar Net Total Flash includes a thin drainage/weep material and flexible flashing attached to a termination bar and drip edge all in one.
Thanks. I found the MTI product, though it’s quite different in construction–I’m not sure yet if that matters to me. York’s product and Mortar Net’s Total Flash are both flashings. I have separate flashing and am looking for a product only to keep the entire cavity clear.
You can just use the regular Mortar Net. It comes in 1 inch and 2 inch thick by whatever height you need. It has the trapezoidal teeth design so that mortar is directed at 2 levels.
Brick veneer on steel studs–we have a condition around windows where the brick is recessed from the remaining face by about 1/2 inch. (We are also using 3 inches of foam in the cavity.) As a result, our cavity depth is under an inch in those locations. I want to make sure that we have a well-drained wall.
ACI 530/ASCE 5/TMS 402, also known as the MSJC (Masonry Standards Joint Committee), requires a 1-inch minimum air space between the masonry veneer and solid sheathing or studs.
The MSJC–specifically Section 6.2 for anchored veneers–is referenced by the IBC. Applicable references are 6.2.2.6.3 for veneer over solid sheathing and 6.2.2.7.4 for veneer over steel framing.
ACI 530 is one of those standards that while generally considered to be “structural” have a number of requirements that the structural engineer considers outside of his scope of work.
For example consider Chapter 13 of ASCE 7 which has provisions related to ceiling systems and anchoring of equipment. These directly impact the architect and MEP consultants yet most architects would say, ASCE 7 what.
ACI 530/ASCE 5/TMS 402 and the IBC requires that you use ACI 530.1/ASCE 6/TMS 602. This is a construction specification. Because the construction specification for masonry is codified it is not clear that you have any option. It is my opinion that everybody has decided to participate in some civil disobediance because I have yet to see any masonry project specification that is compatible with ACI 530.1.
Mark, I beg to differ a little on your response. A lot of the requirements found in the TMS 602/ACI 530.1/ASCE 6 are typically found in many project specifications. In fact, MasterSpec has written their section around the requirements in the TMS Spec. So I think many projects ARE built to the MSJC requirements. Think about cold weather protection requirements. They’re in the MSJC Spec, and those are the same that people have been using for decades. And even though the MSJC Code says a 1" minimum, I think most people design for a 2" cavity because that is what BIA recommends.
The 2 inch cavity “rule” is the one hardest to maintain, (as I will explain) and I think the rationale for it is virtually gone. Our typical wall construction is to put an air barrier/vapor on the sheathing, all insulation outboard of the air barrier, and then brick veneer. As demand for thermally efficient buildings has grown, we are now designing two buildings with 3 inches of foam.
Now cast your mind back to the way it used to be done. Insulation in the studs, but more importantly the “weather barrier” (if it even deserved to be called that) was asphalt felt, lovingly called “tar paper.” This stuff couldn’t stop the water dripping off a cold beer bottle. By maintaining a minimum cavity size, we were sure that mortar wouldn’t bridge the cavity and saturate the paper and the sheathing.
This is no longer an issue when the air barrier/vapor retarder is nearly a waterproofing membrane, though we still need the drainage plane for liquid water.
The 2" design “rule of thumb” will respond to out of tolerance construction behind the insulation better than 1". The air cavity may vary less than and greater than 2". I have seen the starting honch in the foundation formed too shallow, violating the max permitted cantilever for the brick veneer. Hence, the brick will take up some of the 2" air space.
1" was chosen because masons have really thick fingers that get stuck in anything less. I say this in partially in jest but wholly in ernest.
The same screwed up tolerances may exist creating an air cavity less than 1" or too narrow to remove the excess mortar with the trowel that squeezes out the back of the joint and clogs the air space.
Do you specify the mason apply a bevelled mortar bed joint to prevent this squeeze out?
Do you specify the mason use a suspended piece of lath to catch the mortar droppings? This is an old school technique that has disappeared from the job site.
Wayne-good points. I think we’ll be okay with tolerances because the cold-formed framing backup can be erected with tighter tolerance that the primary steel frame. But I will look more closely at that. Fortunately, this tight condition is very limited in scope.
We specify the beveled bed joint but not the snot-stick. I’ve never been able to get anyone to do it, and as a practical matter, with veneer anchors and slightly irregular surface of spray-applied foam, I don’t see how it can work.
There is a difference between fully complying with TMS 602/ACI 530.1/ASCE 6 and incorporating “a lot of the requirements” in our project specifications.
I would appreciate seeing a sample project specification section that fully complies with ACI 530.1. Based on my familiarity with specifications and with ACI 530.1 I believe that such a project specification section is not possible without significant variations from Section Format and Master Format.
I also find it disturbing that ACI 530.1 incorporates contractual terms in the standard that may not be always compatible with the desires of our client.
I have previously requested such a sample from the ACI 530 committee and have had no response.
Keep in mind that not all of the MSJC content is included by reference in the IBC.
In the 2009 IBC, ACI 530.1-08 is referenced only 18 times. Of those 18 instances, only one reference has a vague, broad scope application, and that is Section 2104.1, which states:
“Masonry construction shall comply with the requirements of Sections 2104.1.1 through 2104.4 and with TMS 602/ACI 530.1/ASCE 6.”
My interpretation of that reference, which uses the word “construction,” means the installation of the masonry, or Part 3 of the specification–not Parts 1 and 2. This interpretation is based on the content of Section 2104 and that the previous section, Section 2103, is titled “Masonry Construction Materials.”
Parts 1 and 2 are only applicable when specific articles and paragraphs are referenced by other sections of the IBC.
The content of 530.1, when referenced by the IBC, should be treated like any other code requirement that is incorporated into the project specifications; it doesn’t need to be included verbatim, as long as the requirement remains the same, regardless of how it is paraphrased.
While your interpretation gives some room to argue I suggest that ACI 530 has the last word.
The IBC invokes ACI 530 which in turn states in section 1.4 that ACI 530.1 is “declared to be part of this code as if fully set forth in this document”
If you reference ACI 530.1 by reference then you would have very little content in your construction specification. I would suggest that you go through your specification section and remove all of the items that are addressed in ACI 530.1.
The reference of ACI 530.1 also creates the situation where adhered veneer is automatically a portion of your CMU specification section.
The authors of ACI 530/530.1 did not appreciate the differences between a design specification/Standard and a construction specifiction section.
I would think that if the IBC references the ACI 530.1 document 18 times, that document is ONLY applicable in those specific instances.
This is clarified in Section 102.4 of the IBC which prescribes the exact context of referenced standards.
ACI, no matter its desire, thinking, concept, or statement cannot overrule, supplant or countermand enacted law, which is what the building code becomes when adopted by a jurisdiction.
I have to disagree with the first part of your post.
Like ACI 530.1, ACI 530 is only made a part of the code to “the prescribed extent of each such reference” (IBC Section 102.4). If you look at each of the references in the IBC to ACI 530, you’ll notice that each one is preceded by a specific reference within ACI 530.
There are only four instances in the IBC (2009)where Chapter 1 of ACI 530 is referenced:
for allowable stress design;
for strength design of masonry;
for strength design of AAC masonry; and,
for design of prestressed masonry.
Notice that all of these make reference to the “design” of masonry. Some sections of ACI 530, Chapter 1, have nothing to do with the design, and, therefore, are not made a part of the reference.
If the complete content of ACI 530 were made a part of the building code, much of Chapters 17 and 21 would be eliminated by a single reference to that document.
I agree with the last part of your post. Making a construction specification a part of a standard is not appropriate. The specification should be treated as a guide specification, and any requirement within the guide specification should be backed up by a requirement in the standard.