We live in a townhouse complex and have an exterior wall that is made up from 2x4’s covered with 5/8” thick Type SCX wallboard, covered with building paper which is covered by the exterior stucco. A few yeas back our HOA replaced the shake roofs with tile roofs. In the reproofing process the roofers cut back the stucco to install flashing along the edge of the adjoining roof.







While investigating for a termite infestation in the attic recently we noticed that the roofers severely damaged the sheetrock under the stucco when they installed the flashing for the tile roofs.





This damage was seen in every stud bay in the attic and most likely the same damage is present along the wallboard in our master bath below.

I have a few questions:

How common is it to use Type SCX wallboard as sheathing?

Is the wall compromised with respect to moisture infiltration?

How should this type of damage be repaired?

Thank you for taking the time to read my post and consider my questions.

Howard

 

Just want clarification. They used wallboard as an exterior stratum? Was this original construction?

 

This is original construction. I was stunned when I realized there was only wallboard and paper under the exterior stucco.

I did a search the other day and found this thread.

Sheetrock as Exterior Wall Sheathing!!?? - Contractor Talk - Professional Construction and Remodeling Forum

Maybe this type of construction was permitted in the past for attached townhouses. These buildings were built around 1984.

 

I've heard of this type of exterior wall construction but had never seen it. If I remember correctly, fire resistance was the big selling point. Personally I don't know of any builders that would consider constructing an exterior wall that way.

If the exterior stucco isn't damaged, I assume the best fix would be to fill/repair the sheetrock from the inside with a setting compound like durabond.

 

Mark,

The stucco appears to be sound. My main concern is moisture entering our interior due to damage to the building paper and exterior sheetrock.

Howard

 

Yes, I too would worry about water intrusion. As you can see the metal flashing has nothing between it and the inside of the home. I would show these pictures to the HOA and see what they have to say about the problem. Since they paid for the roofing job they should be the ones suggesting it be repaired correctly. In my way of thinking there should be at least building paper between the sheetrock and the flashing.

 

I spoke with a board member today and he suggested I contact the management company. We plan on staying here for another 20 years so we want to make sure the property is maintained.

 

I would definitely try to find a professional who can take care of damage to a roof as soon as possible. Some roofers may not have the technical skills to do it and make the problem worse.
Roofing Contractors in Sonoma County CA » The Prime Buyer's Report
This is a list of roofing companies where you might find some help with your lumber sliding problem. Best of luck to you.

 

My concern is what sort of drainage plane is required for the system, and whether it was compromised when the flashing was installed for the new roof.

Most such stucco systems assume that water will penetrate through the stucco surface and require the drainage plane behind it to conduct water which penetrates the stucco down to an engineered drainage point below wherever the stucco terminates, normally this would consist of some kind of drain screed or casing bead, which would stand proud of (beyond) the flashing and allow water to drain out onto it:



- Paragon Property Inspections Skokie / Chicago - Illustration of Stucco to Roof Transition at Vertical Surface .

If these various materials are mis-sequenced water flowing down behind the stucco can be conducted into the wall behind the flashing instead of back out over the flashing and onto the roof, it's not unusual to find such problems at both home inspections and inspections of commercial and condominium properties.

I can't say that this installation is wrong based on those pictures, for example there could be some kind of "Z "flashing installed behind the moisture barrier and conducting water out over the flashing - though usually if that's the case you would expect to see a gap at the bottom.

But if I encountered that at an inspection I would attempt to determine the manufacturer of the stucco system, research the appropriate flashing and screed system for that junction, and if it did not appear correct take and send detailed photos to manufacture for comment. If I could not determine the manufacturer, I would recommend evaluation by an experienced local commercial stucco contractor familiar with local best practice and requirements.

 

Michael,

Thank you for your response. It appears the roofers inserted some type of moisture barrier material under the old building paper and terminated it into the new flashing. You can make it out in one of the photos above. Regarding a drainage plane, all we have is whatever space there is between the old building paper and the single heavy coat of stucco that was applied to the chicken wire.

Here is a drawing I made showing the wall construction at the top of the parapet. The drawing does not show the old torch down roof material, which is covered by a Duro-Last roof material and caped off with metal covers. The red in the drawing represents the original building paper that has become brittle.



Here is a picture of the exposed parapet with the metal covers, Duro-Last roof material, and old torch down roof material removed.




Here is a picture of the exposed parapet with the double top plates removed. We opened up the parapet to see the extent of the termite damage. We will replace the top plates and do as much local treatment as possible. We do not want to do any damage to the Duro-Last material on the flat roof or to the adjacent stucco wall. NOTE: The 5/8” wallboard does not extend all the way up flush along the entire length of the 2x10 redwood trim. This leaves a 5/8” gap between the top plates and part of the exterior 2x10 redwood trim. I am thinking about filling this with treated 5/8” CDX plywood.





I want to insert new moisture barrier material over the parapet as shown in the drawing below. Green represents the new material and red represents the old building paper. What type of barrier material do you recommend for this application?



Howard

 

Zuloo,

Thank you for your response. I checked out the link you provided http://www.myprimebuyersguide.com, but it does not cover the county I live in. I plan on using a company that is certified to install and repair Duro-Last roofing after we repair the parapet, but I do not intend to personally take on repairing the damage done to the exterior wallboard by the previous roofers. I will leave that to the Homeowners Association to address.

Howard