Water & Wood Rot Repairs – Siding

When siding repairs are deferred as the house at left illustrates, the repair costs increase significantly. The home owner claimed they didn't realize the damage was there until finishing a basement bedroom for their daughter … and there was a hole the size of a fist, open to the outdoors?

The problem started with leaves piled several feet high on the deck, trapping water against the siding. We didn't check the ledger board attaching the deck to the house as the deck needed to come down. The entire side of the house had to be rebuilt from the siding, plywood sheathing, insulation through to new sheet rock and more. We assumed we would also find structural damage inside the walls but again, the homeowner decided to defer the work give the cost of repairs. This is unfortunate as ultimately this home could be condemned if the exterior walls can no longer support the weight of the house and roof.

Reasons Why Siding Gets (Stays) Wet and Rots

From the top of your home's roof to the bottom of the foundation, you're home is built to shed water. Most of the time it works exactly the way it is designed an built but sometimes problems occur, often when a homeowner adds a deck or sunroom and drainage isn't handled properly.

It rains and that won't change. Your home should shed the water easily, and moving it away from your home so that your house can dry after it rains. Exterior paint sheds water until there are cracks, peeling paint or gaps between the siding and windows/doors letting rain get behind the surface of the siding. It's the water that penetrates that causes problems because it likely won't get enough air circulation to remove the moisture and wood that has more than 20% moisture will rot.

Let's look at the examples illustrated in the photos below, all needed some type of siding repairs.

1. The sunroom here was built well. The water problem resulted from a valley where the sunroom roof met the existing home roof, so water poured down right where the #1 is shown. This water splashed on the deck and up the side of the sunroom, and the wood rot started. We didn't have to replace the windows but the siding and some plywood sheathing underneath had to be replaced above the deck … and below the deck (#2). The long term solution here was to add gutters, to catch and direct the heavy water volume away from the house, avoiding the deck entirely.
2. Immediately below the deck in #1, the entire wall needed new plywood sheathing, a water barrier and siding.
3. The wood clapboard siding here was fairly old and wasn't painted often enough, so the added water splashing up from the deck contributed to the failure of the lowest boards here and elsewhere around the house. The interesting solution here was borrowing siding from the back of the house, to replace damaged pieces in the front of the house … as we could never match the color of the siding (painted). The customer accepted our recommendation to use Azek along the edge of the deck/siding as it won't rot, thus avoiding a repeat of this problem.
4. The water damage in photos #4 and 5 was surprising, for this repeat customer was quite meticulous in taking care of their home. While we began working through a punchlist with multiple items to prepare the home for sale, we quickly found that the random black spots on the inside wall of the sunroom barely told the story. The problem was a result of not one, but several errors in construction after the original home was built. We recommended to our customer that we cut out weep holes in the floor of the deck, to help water drainage.
   • There should be small gaps between deck floor boards to allow water to drain and this wasn't true for this deck. This means when the deck was built, the boards were placed together too closely and when they expanded, the gaps were closed leaving sitting water on the deck.
   • Compounding this problem, the deck had a slight slope into the house where it should have sloped away from the house to help excess water drain off faster. You can tell this by the greater “black stains” closest to the wall of the house.
   • Adding to a poor deck installation, the sunroom roof formed a valley above #4 so you had significantly more water pouring into this corner that lacked drainage. While gutters may be controversial, they are almost a necessity in rainy locations where the roof has one/more valleys.
5. Photo #5 shows how the water from the corner of the wall (#4) traveled along the bottom of the wall and in fact, had started traveling up the door jambs too. We replaced the lower half of the door jambs and all of this could have been avoided if the sunroom was built using pressure treated wood, as it's really an outdoor structure.
6. The siding on the other side of the sunroom door had quite a few black spots, so we used leftover materials to rebuild the wall although you can see that the wall studs are in fairly good shape.

Read the rest of our series on water damage and wood rot repairs …

• Water & Wood Rot Repairs – Roof
  
• Water & Wood Rot Repairs – Siding … this article
  
• Water & Wood Rot Repairs – Windows
• Water & Wood Rot Repairs – Doors
• Water & Wood Rot Repairs – Decks
• Water & Wood Rot Repairs – Exterior Trim