Should I replace all the sheathing and air seal the interior when re-siding?
MikeonLI
| Posted in General Questions on
Homeowner Long Island ny. Getting new siding put in soon. Based on some exploratory work I’ve done and previous gutter issues I likely have a good amount of sheathing damage. I plan on using a self adhered wrb as my exterior air barrier. The house itself is quite drafty. Given that, is it worth removing all the sheathing and doing an air tight drywall approach from the outside. That way I could have both an interior and exterior air barrier. It might go a long way for comfort in a drafty house
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Replies
Hi Mike,
Usually, we don't replace all the sheathing unless there is extensive damage throughout the structure, at that point, you may also have damage to the framing. I visited a home with these issues last spring. The builder almost didn't open up the sheathing because it looked okay, some staining but intact. He decided to cut open a small area just to peak and found heavy structural damage. My takeaway from this experience, if the sheathing is discolored or feels a little punky, do a little more investigating. This photo shows the home.
As far as using the exterior sheathing as the air barrier vs a self-adhered WRB, in my experience, both can be effective air control products. It you are planning on installing a self-adhered WRB, I'd use that product as the primary air control. If you move to a mechanically attached WRB, tape the seams of the sheathing and call that the air control. Pay attention to how you are connecting the air control to the foundation, and if possible, to the interior ceiling air barrier.
Randy
Thanks Randy. Excellent tips and advice. That picture shows incredible damage.
One question. Since there’s so much draftiness and I have no idea how well the workmanship was done when the house was built, I figured removing all the sheathing might give a good chance to also remove the insulation and air seal with spray foam all the places where the framing meets the drywall. Sort of like an airtight drywall approach but from the outside.
Given the house is large and leaky, I figured this may give some benefit for comfort overall, especially given the fact that I think the original builder took shortcuts that can be causing some of the issues I’m seeing.
What do you think?
Mike - I probably wouldn't remove all of my sheathing if it wasn't damaged. I wouldn't want to leave the walls exposed to the elements any longer than necessary and I could see it potentially popping sheetrock screws. As Randy mentioned, sealing the sheathing can significantly reduce drafts. Make sure to seal around doors, windows, and wall penetrations while the siding is off. If you find the results aren't satisfactory, you could look at sealing the top plate to the sheetrock (assuming you have attic access). If you have a basement with access to the rim joist, you can install rigid foam and seal around the perimeter with canned foam. Also look for electrical and plumbing connections that exit the building or enter the exterior wall cavity just inside the rim joist and foam them. If you have a block foundation with open tops, you can seal them with foam as well. Finally, I would look at the weatherstripping on all doors and windows.