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Stucco expansion joint at window

Danny Pritchard

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Gosh, it's been a long time since I took the course to be certified as a third-party EIFS inspector and I decided not to provide that service. (Too much guesswork and liability.)

But, having said that, if I recall correctly, it was always suggested that expansion joints align with one of the jambs. Also, should there not be backer rod and sealant around that window?

That would depend upon exactly which system is installed. It is important to find out whose product this is and what they specifically recommend regarding installation.

There's practically no EIFs in Richmond and I'm completely out of practice.

Frankly, when I end up inspecting a home that has more than just a little EIFS for accent, I tell them about the potential problems and strongly recommend that they have a thorough inspection by a certified EIFS inspector.

One of my colleagues who became certified before me by the same institution has been doing them for several years. He is beginning to have second thoughts about providing the service himself. It's a tough inspection with no guarantees and a lot of potential liability. He told me recently he's about to find out just how much liability, if you know what I mean.

As an HI you MUSt pay special attention for any staining on the interior around all openings and be sure to check for moisture under openings. I also look for any exposed reinforcement especially on the bottom edge of the system. If the top edge of projections are not sloped mention it as a potential problem. Flag any cracks in the system.

Above all, cover your %ss!

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Les is most likely to know the answer, but I can't imagine it's going to make any difference.

As a mason, I've actually installed that 3-coat system, but it's been about 27 years ago, thankfully. I like that finish! They did an exceptional job. We always did a sand finish using a cork float.

There aren't many of those guys around anymore. Learning to use a hawk and trowel is a trip. Until you get it down, more mud ends up on your shoes than on the wall. [:-crazy]

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I'm not sure what is the concern.

Expansion joints are not a requirement anywhere, except indicative of good workmanship.

Why would you feel the expansion joint is wrong?

Don't think I'm setting you up, just simply asking.

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This is an aesthetic or control joint, not an expansion joint. These joints are used to control cracking. They are usually required every 144 sq. ft. of area. Refer to the particular manufacturers installation instructions for specifics.

Also, I do not think this is a three coat system. Most likely it is a "one coat" - base coat plus finish coat.

There should be a 1/2" - 5/8" gap at the window with backer rod and DOW 795 caulk installed.

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I was wondering. Never seen a 3-coat stucco installation like that.

In fact, expantion joints in 3-coat stucco are typically formed by a special pre-formed galvanized metal "W"" shaped strip (it expands and contracts like an acordian) that uniformely creates that break through all coats and the lath.

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I realize and appreciate that you are on a mission but please do not hijack someone else's thread in furtherance of your cause. He's asking about this particular accessory joint. That should be the focus of this discussion. If you want to post your photos do it in one of your previous threads or start another.



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Whether it is an expansion joint or a control joint, the correct term is "trim accessory" joint - either expansion trim accessory joint or control trim accessory joint.

That looks like a control trim accessory joint, not an expansion trim accessory joint. There's nothing wrong with ending a control trim accessory joint on top of a window as long as the stucco ends in a casing bead and there is a metal head flashing below the casing bead that is properly incorporated into the assembly. The lath is continuous behind a control trim accessory joint so expansion isn't the concern - cracking is.

If it's an expansion trim accessory joint, it should be located directly over either horizontal or vertical framing, imbeeded in caulk at the terminations and the gap needs to be filled with backer rod, caulked and tooled.

The thing I'd be concerned about is the size of those squares. There's a rule that says trim accessory joints must be installed in the longest possible lengths and may not terminate within 24 inches (600mm) of an intersection with the exception of pre-manufactured trim accessory joint intersections. That doesn't look like a pre-manufactured intersection to me. What size are those squares?



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This is from The Stucco Guide:

Trim Accessory Joints
  • 1.Trim accessory joints refer to various types of control joints, expansion joints, reveals and/or any other devices or systems that divide (break) the stucco membrane surface.

2. Architect is to select the type of joint and indicate on drawing the location of joints.

3.It is recommended that control joints be installed for the purpose of controlling the location and the amount of cracking that might occur.

4. Trim accessory joints provide aesthetic value to the stucco surface.

5. The installation of control joints is not an assurance that there will be no cracking in the stucco, nor is it an assurance that cracking will occur only at the control joint locations.

6. The type of building, the design of the exterior walls and the entire stucco system dictate whether control joints should be used and the number involved.

7. Trim accessory joints provide relief of stresses from the structure.

8. Trim accessory joints provide for a plaster stop, a screed for the stucco and stress relief point for th stucco.

9. Trim accessory joints accommodate expansion and contraction to relieve the stress present int cement plaster membrane during curing.

10. Locate joints strategically at points where building movement is anticipated, such as wall penetrations, structural plate lines, junctures of dissimilar substrates, existing construction joints in structure, cantilevered areas and where columns or beams join the walls or soffits.

11. Framed and sheathed construction requires control joints installed more often than in latch-reinforced stucco systems over concrete or concrete masonry surfaces. The use of control joints in a stucco system direct to the concrete or concrete masonry substrate is limited.

12. A horizontal trim accessory joint is recommended at the floor line on multistory framed construction. The architect and/or engineer needs to take into consideration the shrinkage and the compression perpendicular to grain of the wood framing members for the location of joints and the type of joints.

13. Control joints provide for better quality plastering work because they serve as a screed for leveling of the cement plaster, a uniform thickness ground and termination points.

14. The water-resistant barrier must continue unbroken behind trim accessory joints.

15. It is recommended that trim accessory joints be installed in framed and sheathed construction so as to create stucco panels of approximately 150-180 square feet, (14m sq. to 17m sq.) in as square a configuration as possible. Maximum recommended length of a panel is 18feet (5.5m). Panel size should not exceed a 3t0-1 ratio.

16. It is recommended that trim accessory joints be installed with concreter or concrete masonry construction so as to create a stucco panel (with lath reinforcement) of 200 square feet (19m squ.).

17. Installing control joints over continuous lath is an approved method, but not when it is to function as an expansion joint. Control joints are a one piece trim accessory.

18. The recommendation for installation of expansion joints or reveals is to break the lath and lap it over on top of each of the flanges. Control joints may also serve as expansion joints if so specified and detailed.

19. Expansion joints and/or reveals may consist of one or two pieces.

20. Control joints are limited in their degree of movement. Expansion joints provide greater movement.

21. It is recommended that trim accessory joints be weather-sealed by embedment in caulking or intersections, when placed end-to-end, abutting one another and at terminations.

22. It is recommended to install vertical joints continuously and to abut horizontal joints to vertical. The use of horizontal reveals, flashing designs and/or other horizontal surface breaks may prevent continuous vertical joints.

23. Install longest possible lengths continuously. No termination of a section within 24 inches (600 mm) or an intersection, with the exception of pre-manufactured trim accessory joint intersections.

24. Aluminum and/or PVC reveals require that when the lath is installed over the flange, it totally covers it. The welded wire and woven wire latch hall be installed so as the crotch of the lath is over the flange.

25. Sheathed framed construction with vertical trim accessory joints that required the latch to be terminated (cut) and installed on top of the flanges shall be provided at framing member locations. Lath shall be attached with appropriate fasteners through the trim accessory flange, sheathing and into the framing member. The lath/flange on each side of the trim accessory joint is recommended to be attached to a framing member. Double framing supports may be required at these locations. This condition does not pertain to control joints installed over continuous latch.



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All that said; I'd have put the joints over the corner of the window nearest the exterior corner of the home. That's where I always see the cracks.

A perfect control joint would run in a jagged diagonal line from the window corner to either the wall/ceiling joist juncture or the nearest level change of a platform framed home. It's going to do what it wants...I just want to facilitate nature and make it look like I planned it.

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"That looks like a control trim accessory joint, not an expansion trim accessory joint. There's nothing wrong with ending a control trim accessory joint on top of a window as long as the stucco ends in a casing bead and there is a metal head flashing below the casing bead that is properly incorporated into the assembly."

No casing bead.No head flashing.These are items that are only seen on commercial construction in this area.

Also the the square is roughly a 12' x 12' area.

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That's your answer then. It's wrong because there isn't any casing bead or a head flashing above the window and the stucco is applied all the way to the windows without benefit of backer rod or tooled sealant.

It doesn't matter whether it's only seen in commercial construction in your area or not. That only means that stucco contractors in your area are doing sub-par work and it's wrong because it wasn't done to the minimal acceptable standard as prescribed by ASTM.

Write it up. Get smart about stucco and then start getting contractors in your area smart about stucco. Do it enough and get every other inspector you know in your area, as well as the muni inspectors to write it up, and sooner or later the stucco guys will start to learn their lesson and will change their ways.



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