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Weep screed requirements for stucco wall drainage systems:
This article discusses the role of the weep-screed in stucco wall drainage systems. The discussion includes a definition of weep screed, citation of building codes relevant to weep screeds, and references to expert sources on weep screed requirements & specifications for various stucco wall drainage systems.
The page top illustration, adapted from Dryvit Corporation's foundation weep screed specification details, shows the position of the stucco wall coating weep screed at the wall bottom where it serves to any wall water penetration to the building exterior. [Click to enlarge any image]
This article series discusses best practices construction details for building exteriors, including stucco exteriors, exterior caulks and sealants, and choices and application of exterior finishes on buildings.
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[Click to enlarge any image]
The stucco wall weep screed is a component specified by stucco wall system manufacturers to assure that any water that penetrates the wall coating, such as at leaks around the mounts for exterior lighting or at windows or doors will be drained safely to the building exterior. Click to enlarge the page top weep screed schematic and you will see that a proper weep screed installation must integrate this wall bottom flashing among (typically) seven layers of materials outside of the building's structural wall sheathing.
Proper placement of the weep screed is at the bottom of the stucco wall coating, extending visibly to the building exterior and installed between the building housewrap or air/water barrier and any manufacturer-specified wall flashing system. Common mistakes that can lead to water trapped within the stucco wall system include
Because these SNAFUS do occur, stucco experts (cited here) prescribe remedies for weep screed repair or retrofit to reduce the chances of wall damage from trapped water. This article is a continuation from STUCCO EIFS DRAINAGE SYSTEMS
I have just built a modern home with first floor (slab on grade) stucco exterior (in Minnesota). I've had some difficulties with the builder. After final inspection - it was noted that there was no "weep screed". The builder said for cosmesis - the screed was under the stucco. It seemed fishy and after a few go arounds between lawyers, he agreed to remediate the stucco. When the stucco was off the house - I took pictures and there was no metal lathe under -- the lathe was placed by the stucco vendor secondarily and a screed now exists for 90% of the house.
He ignored several small sections (reverting to his assertion that the screed exists - it's under the stucco and the remediation he agreed to was just for cosmesis) This yard is very wet so it's hard to believe that some of the stucco, but not all, needs a vapor escape system.
MN Lathe and Plaster won't let me pay them to come and give an opinion. The city inspector (who passed the house initially) is not willing to comment... so I am left to believe the builder who has been untruthful about the project from the beginning, has honestly remediated the faulty stucco.
The first two pictures are of smaller areas he blew off fixing. In these areas, the stucco sits on concrete (and if the grading is appropriate) -perhaps it doesn't matter.
The third picture is on the side and it sits in a swamp of a lawn. The drainage is atrocious and sitting water is up against that stucco every time it rains. The screed above the retaining wall ends 3 feet above the ground; below the retaining wall - there is no (visible) screed. He claims it's there. This wall is against my dining room-- I'm very worried about damage.
The fourth picture is chronologically the first. This is the day the stucco vendor returned to remediate the stucco. I hope you can see - despite my contractor's insistence that I was being picky - there is NO lathe under this stucco, and no weep. I am left to believe that there is an appropriate moisture vent on the parts he chose not to fix?
The last picture is the stucco job around a back window - I assume that moisture barrier applies to openings like windows as well and it seems very poorly done to me.
I have no idea where I turn as a consumer if the city residential building inspector won't help and the state Lathe and Plaster bureau won't help.
This question was posted originally at STUCCO WALL METHODS & INSTALLATION
Anon: Use our email at CONTACT at page bottom to send some photos for comment.
Also if you can find the brand of stucco product that was applied we can help you obtain the manufacturer's specifications.
These issues are too common and I agree, frustrating. The building inspector doesn't want to get in hot water so doesn't want to re-visit a site where s/he may have either made an error or been influenced by the contractor. The contractor wants to cut their costs.
If you cannot obtain an absolutely credible independent and well documented inspection and report of any additional repairs or corrections needed you'll be stuck in an endless loop of arm-waving, finger pointing, dodging and weaving among participants.
In a reply to your earlier query I suggested identifying the stucco system manufacturer used by the contractor and through them obtaining a copy of the stucco installation specifications. That's the bible of "correct" installation of the product and without that you're also stuck with arm-waving.
If you can find an EIFS system inspector who can examine your site and who can compare findings with specifications at least you'll know if additional repairs or corrections are needed for the installation.
If you agree I can publish your photos and information, keeping you anonymous unless you want to be identified. That may permit additional helpful comments from some of our more expert readers.
Feel free and thank you. (I would prefer to remain anonymous if possible).
Do you have concerns about the stucco around the window in the picture I sent?
Any reader corresponding by email can opt to remain anonymous in discussions that together we may agree might be helpful to others.
About the windows, we're missing details but it looks as if they're not sealed. We need to start with the specs to compare with the actual installation.
He [the builder] says: "Your home is not EIFS. It is Dryvit brand acrylic finish coat over a traditional concrete base coat. This is the best system available. There is a weep in that area near the screen room under the stucco, but as mentioned, questionable aesthetics in re-exposing it. Will do you as you wish."
Hopefully that means something to you. I believe I understand (and my contractor does not) that you, by definition, can't have a weep screed (drainage system) which is "under" the stucco.... the point is for the moisture to wick up and have an egress line above the ground, right?
Dryvit manufactures Exterior Insulation and Finish Systems (EIFS) - http://www.dryvit.com/residential/
But I agree that there are other types of finish systems. The essential feature of EIFS is that the synthetic stucco coating is applied atop a mesh fabric that is in turn installed over solid foam insulating board.
If your home's walls are solid masonry - concrete - then the weep screed question is moot. If your home has a stucco system installed over a wood framed walls then note the code comments at the end of my remarks.
Dryvit's commercial publications such as http://www.dryvit.com/fileshare/doc/us/description/ds247.pdf
describe the weep screed. - quoting
As with any cladding, stucco must be designed and installed properly in order to perform as intended. Some cracking is inevitable with any stucco, and moisture will penetrate through the cracks. When designed and installed properly over lath, this moisture settles on the external surface of the Code required weather-resistive barrier and ultimately, via gravity, drains down and out of the wall via a weep screed. Dryvit recommends that all applicable Codes be followed, ASTM guidelines maintained, and that all work is performed by a contractor familiar with these as well as the installation of stucco.
And this Dryvit schematic shows how the weep screed should be installed
Take a look at that schematic and you'll see that the essential feature is a combination of "backstop" air and water barrier that laps atop the upper edge of a metal flashing that directs any moisture that might penetrate the system out at the bottom of the wall.
Note also that the schematics do not show stucco extending to soil contact - a situation that may not drain, that may depending on construction invite insect pests into the structure, and may not be code compliant (I'm not certain of the last remark - depending on where you live.)
A stucco information website author, the "Stucco Guru" at
discusses weep screeds in more detail - I read and agreed with his comments. He cites these older code notes - where you'll see he too shares my worry about taking the wall bottom drainage system right down to the ground.
The 1985 edition of the UBC states, in Section 4706 (e) of Chapter 47, that: "A minimum 0.021-inch (No. 26 gauge) corrosion-resistant weep screed with a minimum vertical flange of 3's inches shall be provided at or below the foundation plate line on all exterior stud walls. The screed shall be placed a minimum of 4 inches above grade and shall be of a type which will allow trapped water to drain to the exterior of the building. The weather-resistive barrier and exterior lath shall cover and terminate on the attachment flange of the screed."
Concrete brick pavers, natural stone, ceramic or quarry tiles or other construction materials are not to be placed, subsequent to installation of lath and plaster on vertical walls, in a manner or at an elevation that would block the weep screed from providing drainage from behind the wall system. ....
Note that the building code does not suggest installation of a weep screen on other than frame walls. ...- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015
WEEP SCREED INSTALLATION
Weep screeds are metal devices installed at the foundation plate line of exterior plaster walls if the walls are of stud framework. The screeds are intended to provide relief for the exit of rain water which might possibly intrude into a building at or near the roof, at vent pipes which pierce the roof, at a chimney, at or around windows or doors, or at other possible locations about a structure. ...... Installation of weep screeds at foundation plate lines of framed, plastered walls is required by the Uniform Building Code ...[ as ] first published in ... 1973 Uniform Building Code. That -1973 edition stated: "A weep screed shall be provided at the foundation plate line on all exterior stud walls. The screed shall be of a type which will allow trapped water to drain to the exterior of the building." ... The requirement is always incorporated in Chapter 47 of the UBC.
1982 UBC Section 4706(e),Chapter 47
A weep screed shall be provided at or below the foundation plate line on all exterior stud walls. The screed shall be placed a minimum of 4 inches above grade and shall be of a type which will allow trapped water, to drain to the exterior of the building. The weather-resistive barrier and exterior lath shall cover and terminate on the attachment flange of the screed. ...
1985 UBC Section 4706 (e), Chapter 47
A minimum 0.021-inch (No. 26 gauge) corrosion-resistant weep screed with a minimum vertical flange of 3's inches shall be provided at or below the foundation plate line on all exterior stud walls. The screed shall be placed a minimum of 4 inches above grade and shall be of a type which will allow trapped water to drain to the exterior of the building. The weather-resistive barrier and exterior lath shall cover and terminate on the attachment flange of the screed.
Concrete brick pavers, natural stone, ceramic or quarry tiles or other construction materials are not to be placed, subsequent to installation of lath and plaster on vertical walls, in a manner or at an elevation that would block the weep screed from providing drainage from behind the wall system. ...
Unless instructed otherwise, a lather probably would attach the weep screed to the toe plate or bottom plate of the elevated framed wall above the deck or roof section, just as is done at the foundation plate line.... It is necessary that a waterproof deck membrane be extended vertically upward on walls beside a balcony deck, to an elevation which will allow safe overlap of building paper on the wall, downward over the top of the deck membrane. The height to which the waterproof deck membrane is extended upward on an adjacent vertical wall may limit the elevation at which the weep screed may be placed. The reason for that possible limitation is that the weep screed, as well as the building paper weather-barrier installed behind plaster on the adjacent wall, must adequately overlap the top of the vertical segment of the waterproof deck membrane a safe distance. If the waterproof deck membrane has not been extended upward a sufficient distance on the wall, the weep screed must, of necessity, be placed lower on the wall than is desirable.- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015...
A related blocking problem frequently occurs at ground level, on construction projects. Sometimes builders or their concrete subcontractors place concrete against a vertical plaster wall at an elevation higher than the weep screed. ...
It is advisable that a strip of asphalt-saturated felt, R-15 building paper, or other good building paper, at least 8 inches to 9 inches in width, be placed over the top vertical flange of the weep screed or plaster stop, to rest upon the outward protrusion of the metal trim, prior to placement of lathing paper.- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015
REMEDIAL TREATMENT OF A BLOCKED WEEP SCREED
If a builder, concrete contractor, masonry contractor, or a home owner, has blocked the weep screed installed at the base of a wall, the problem may be remedied. Also, an individual may desire, for any reason, that an additional opening be formed at the base of a plaster wall, where that wall joins a horizontal or sloped surface, such as at:
- the juncture of a wall with a balcony deck;
- where a wall joins a flat or sloped roof surface;
- at the top of tiles which had been installed vertically or horizontally against the base of a plaster wall;
- immediately above and parallel with the top of a concrete slab, concrete stairs, a brick-paved surface; or
- a concrete balcony deck.
To make that type of opening, a saw cut may be made in the plaster membrane, at some convenient and appropriate level above the base. That distance could be as shallow as 1/8 inch to one or several inches above the surface of the slab, balcony deck or roof. The saw cut should NOT cut through the entire thickness of the plaster membrane. The purpose of that admonition is to protect the weather-barrier of lathing paper, and the up-turned waterproof deck membrane, located behind the plaster, from unnecessary damage. The weather barrier on the wall and deck membrane should not be violated.
A saw cut which extends approximately one-half to two-thirds through the thickness of the plaster membrane should be adequate. After the masonry saw blade has cut partially through the thickness of the plaster wall, an edged, wedge-shaped device should be driven carefully into the saw kerf, to fracture the remaining thickness of the plaster wall. The weather-barrier behind the plaster is not to be pierced. Shattered pieces of plaster should be removed from below the horizontal cut, and all debris cleaned from the void.
Subsequent to cleaning debris from the newly-created void, the exposed barrier membrane behind the plaster could be examined by means of a mirror to determine if the weather-barrier membrane had been cut in any place. If a cut is found in the barrier, the perforation should be brushed with asphalt emulsion or cut-back, or other good sealant, to effectively seal the penetration.- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015
The Stucco Guru original author includes additional detailed weep screed remediation suggestions and reiterates the importance of not blocking weep screed drainage openings:]
... Alignment of the weep screed must comply with Section 4706(e) of the applicable edition of the Uniform Building Code. ... I have observed that .. paving ... has been placed against the base of a plaster wall where a weep screed had been installed, but was placed at a finished elevation higher than the screed. That material ... blocked the weep screed and reduced its effectiveness ....- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015...
REMEDIAL TREATMENT FOR MISSING WEEP SCREED
On a project on which weep screed has not been installed where required by the Uniform Building Code or by project drawings prepared by the architect, the following remedial procedure is recommended.
A saw kerf could be cut partially through the plaster membrane, a short distance above the base of the plaster wall. A diamond-tipped circular saw blade serves well to accomplish that action. Subsequent to cutting the partial-depth saw kerf, a wedge-shaped tool (chisel, pry bar or other) should be driven into the saw kerf, to fracture the remaining thickness of the plaster. That combination of partial-depth saw kerf plus fracture will provide adequate exit for possible intruded water. That is all the remedial work that is necessary to compensate for omission of weep screed.
I do not recommend breaking away plaster from the base of a wall, to install a weep screed after construction. That action would be over-correction, and the final result might not present a satisfactory appearance.
Note that no remediation is needed if water is not intruding into the building system.
- "Stucco Guru", http://www.stuccoguru.com/resources/article.cfm?articleID=B-05300&resourceID=3 retrieved 8 July 2015
... Finally - well it's never final is it - take a look at Dryvit's documents on moisture drainage
Without question, even if the weep screed was installed everywhere it should have been, places where the wall drainage outlet is blocked are potential moisture traps and potential trouble. The actual risks depend on the specifics of where the drainage was omitted.
Here is Dryvit's installation specification for their NON-EIFS residential system
The company's term for this system is TAFS - I can't know if this is what you bought but as your builder says it's DryVit and non-EIFS this may be what you've got.
TAFS™ over Residential Non-EIF Systems
Textured Acrylic Finishes
Is there any way a stucco vendor or a general contractor could think that exterior stucco could egress moisture satisfactorily with an "interior" screed placed UNDER the stucco?
The weep screed is required or specified by stucco system manufacturers such as DryVit for wood framed structures. It may not be needed at all on a solid concrete wall structure.
Where the weep screed is required it should follow the stucco system manufacturer's specifications. That includes bringing water to daylight at the bottom of the foundation wall and not blocking that drainage exit. It seems to me that if the flashing that constitutes the weep screed is not at all visible it is likely to have been blocked by stucco or other materials.
A very careful close-up look at the wall bottom from the building exterior should show the wall bottom flashing and its ability to drain. If that edge is sealed or no flashing is visible it seems likely that something is wrong: either the weep screed was omitted or it was covered-over such that it cannot do its job.
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