Q&A / 

Leaking Cedar Siding Water Stains Inside

Quick Column Summary:

  • Garage sided with no sheathing material
  • How to stop water from entering
  • No easy fixes
  • Remove siding and add sheathing, tar paper or house wrap

Judy Saulle, who lives in a cedar-sided house in Earlysville, VA, has an interesting problem with her house. 

"Our garage does not have any sheathing just cedar siding nailed  to the studs.

We want to use the space for storage but the the walls are all water stained. We're looking for a simple solution to fix the problem from the inside.

We thought about using flashing tape to cover the areas where rain comes in or foam insulation boards to fit between the studs but we are afraid of causing a mold problem.

Do you have any suggestion? Look at our photos. We need help!!!"

You can see water stains. Photo credit: Judy S.

You can see water stains. Photo credit: Judy S.

siding exterior

Here's my answer to Judy:

Judy, there's no way to stop the water from the INSIDE.

I'd like to see you do a test. Can you secure a garden hose that has a spray nozzle to the siding so the gentle spray from the hose is aimed DOWN the siding?

I'm trying to simulate a rain shower on the siding. I don't want the water running sideways or UP.

Someone needs to be inside the attic and watch for active leaks while the water streams down the siding.

The water could be coming in because of capillary attraction. You need to verify this.

Ordinary lap siding doesn't leak because of the laps.

To ensure you never have future leaks, just take off the siding and install sheathing and felt paper or house wrap and do the job right.


2 Responses to Leaking Cedar Siding Water Stains Inside

  1. We just built a cedar home, and did most of the work ourselves. My husband and I both are DYI people and have experience in building. We have built a total of 8 homes. However, this is our first cedar/stone home to build. Our problem: Water is coming in somewhere around or through the cedar plank siding. We thought by wrapping the house in house wrap, this wouldn't allow for any water to come through the cedar shingles. My question is: Will a waterproof sealer or paint stop the leaking? We also thought about caulking between where each cedar plank meets. What is your suggestion?

    Thank you,

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