Seal gaps at window / trim joint?

[inspectorwill]

The pictured installation is typical for my area. This is a traditional stucco home with wood trim installed around vinyl clad windows. The window / trim joints are commonly caulked. However, the caulking typically deteriorates within a couple years. Recaulking on a regular basis, especially at 2nd floor windows, does not seem practical. In the close up pic, you can see the lathe in the gap between the window frame and wood trim. I have two questions. 1- Is the caulking really necessary? 2 - Is there a better installation method with this type of siding and trim? Gaps will inevitably occur between the window frame and wood trim and continual caulking is not practical.

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[Jim Katen]

The pictured installation is typical for my area. This is a traditional stucco home with wood trim installed around vinyl clad windows. The window / trim joints are commonly caulked. However, the caulking typically deteriorates within a couple years. Recaulking on a regular basis, especially at 2nd floor windows, does not seem practical. In the close up pic, you can see the lathe in the gap between the window frame and wood trim. I have two questions. 1- Is the caulking really necessary? 2 - Is there a better installation method with this type of siding and trim? Gaps will inevitably occur between the window frame and wood trim and continual caulking is not practical.

I'd expect that a structural sealant joint, with backer rod and good-quality sealant would last at least 5 or maybe even 10 years. But it's got to be applied properly.

- Jim Katen, Oregon

[hausdok]

Hi,

The stucco is going to move and vinyl windows will expand at twice the rate of aluminum wood or fiberglass, so keeping the joint sealed is a challenge with the trim flush to the face of the stucco.

Jim's solution will probably work, if it's used on both sides of the trim, but the stucco guide shows another solution. The window is flashed with flexible bituthene flashings over the nailing fin at the sides and top and under the fin at the bottom; the stucco ending in a treated wood nailer/plaster stop butted right up to the sides of the window casing at the sides; a 1/4-inch gap between the casing and the stucco at the bottom; a 3/8-inch gap between the stucco and the casing at the top; and then the trim is applied over the plaster stop. A metal head flashing laps them both at the top, and then the gap at the bottom is filled with backer rod and tooled with sealant.

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[Scottpat]

Backer rod and butyl rubber sealant would be the best option, IMHO.

[Tom Raymond]

Terpolymer or polyurethane will out last butyl by several years.

Tom

[hausdok]

Terpolymer or polyurethane will out last butyl by several years.

Tom

All joints on stucco walls need periodic inspections and maintenance. It's not a question of outlasting, it's a question of staying flexible so it can handle the differences in range of movement of the vinyl, trim and stucco; that means that one must use backer rod or the caulk will be defeated by the movement regardless of what it is.

ONE TEAM - ONE FIGHT!!!

Mike

[Erik]

Mike, Is it ok if I down load you're two illustrations? I sure would like to use them some time.

[hausdok]

Sure, go for it, but give credit where credit is due - The Stucco Resource Guide from the Stucco Manufacturer's Association.

OT - OF!!!

M.

[patches51]

what is a window joint? Is it actually on the window or around it?

[Marc]

what is a window joint? Is it actually on the window or around it?

'Joint' refers to contact between dissimilar materials such as between a vinyl window and an adjacent stucco wall finish.

Marc