To Rot, Or Not To Rot, That Is The Question

The Unseen Threat To Every Home


Published on 03 Feb 2017

In the last few months we've encountered a rash of restoration projects where unknown structural rot caused significant, costly damage. So, we thought you should know what we've learned and what to look for in answer to this critical question—Do you see signs of rot in your home?

The shear power of water to carve rock on display in the Grand Canyon

Remember, all it takes for rot to occur in your home is exposure to moisture and time—the same two things that made the Grand Canyon. Okay, we know that took a bit more time, but the same principal is in play. Water is powerful. And trapped inside a home, it is also destructive.

A Tale of Three Cities

These three Twin Cities stories we are about to share with you are somewhat different, but they share chilling similarities and lessons in home ownership.

So, to quote The Bard, “If you have tears, prepare to shed them now.”

The slow trickle

1 A Flood by Any Other Name

Our first story involved a master bath remodel needed after the sink overflowed. These Long Lake homeowners knew the flood had soaked the wall of their lower garage and assumed some clean up and new drywall would solve the problem. But when the wet drywall was removed it exposed rotted framing from water that had been leaking from outside for literally decades.

Water damage and rot exposed in garage
Interior and exterior mold/rot exposed. Note studs nearly rotted away.

“Every time they removed another board or section of drywall they found more water damage, wood rot and mold,” the homeowner recalled.

How did this happen? The primary cause of the extensive damage was an elevated deck that was not flashed properly where it was attached to the house. The Murphy Bros. team, led by seasoned design/build consultant Jeff Robinson, also discovered skylights installed in the cedar shake roof had leaked over time. And a premium brand shower valve installed when the house was built had dripped inside the wall for an unknown length of time.

Water intrusion visible at Improper flashing around skylight perimeter

"The homeowners thought they were just going to remodel the bathroom and replace some drywall downstairs after the flood. Ultimately they had the nightmare of mold mitigation and repairing all of the structural damage to the house and deck before they could even start on the dream bath with its large tile shower, custom cabinetry and elegant free-standing soaker tub," explains Robinson.

After skylight repair
New deck posts, joists, decking, roofing around skylights and low-maintenance aluminum railing.
New bath after rot repairs

​But O, How Bitter a Thing It Is

If you read no further at least understand this essential rule: unless metal flashing and waterproof membranes are carefully installed everywhere they are required during construction and the usual suspects are periodically inspected, the structure of your house may be taking on water, rotting from the inside. Once that begins, other unpleasant things can invade your home: mold, carpenter ants, mice, hornets, and a host of other unwanted guests, in-laws not included, without your knowledge.


And the longer the problems go undetected, the more dangerous and costly the outcomes.

Like the tip of an iceberg water intrusion and rot can appear small at first

Now Is The Winter of Our Discontent

“Nothing makes me feel worse than telling a homeowner that if $20 worth of flashing had been installed 20 years ago they could have avoided $40,000 in structural repairs today,” said Murphy Bros. President John Murphy.

Actually, Murphy acknowledges it could in fact be worse. Imagine a 2nd story deck collapsing due to structural rot during a graduation party and taking everyone with it. Or a family that develops chronic respiratory problems from unseen airborne mold. Then there’s the mental trauma from disrupting a colony of thousands of carpenter ants that were attracted to the wet wood. Trust me: That’s a scene you cannot un-see, particularly if you were below at the moment of discovery.

2I Wasted Time, And Now Doth Time Waste Me

Our second story involves a New Brighton couple who had built their home 41 years ago and had added a sunroom and multi-level decks off the back of the home. Last year, they asked the painter who had been cleaning and re-staining the decks over the years to replace a few rotted cedar decking boards.

Note lighter colored deck boards lower right indicate initial damage repaired

When the painter removed a board by the corner of the sunroom he discovered the rotten, wet wood extended into the structural framing and the sunroom wall. There also were signs of carpenter ant damage in the sunroom framing. The homeowners called Murphy Bros. because they had recently used them for their kitchen remodeling.

The real damage was underneath
Decking flush to patio door without proper flashing

Murphy Bros. discovered that the decking was virtually flush with the patio door and that no flashing had been installed over the ledger board where the deck joists were attached. The crew had to replace most of the home’s rim joist, sill plate and deck ledger, the corner of the sunroom, many deck posts and all of the decking, staircases and guardrails.

Structural supports were compromised

“If someone had leaned on the deck railing they probably would have gone over,” the homeowner remarked. Actually, Murphy said the ledger was so bad the whole deck might have collapsed.

When the deck was built, these homeowners had no idea the floor should have been set lower than the patio door or that metal flashing was needed to divert water away from the structure.


“Actually, building practices that were common during the 1980s wouldn’t meet today’s codes for deck ledger attachment and flashing, guard rails or handrails. For instance, back then you could get away with notching 4x4 cedar rail posts and just bolting them together,” explains Murphy. “That wouldn’t meet code today, but it’s a bad idea regardless of when the deck was constructed.”

“If you notch the post it creates the perfect place for water to get in and cause the lumber to rot or split. Plus cedar is a soft wood and you only have the equivalent of a 2x4 when you notch. With leverage against the top of the rail it’s not strong enough to support a person’s weight, Murphy explained.

New deck nearly finished

3What Rot Through Yonder Window Breaks?

Water traveled 12 feet vertically from this sunroom behind the brick into the garage foundation

Our final story involves a Plymouth home where water intrusion and wood rot developed from a four season sunroom assembly that had pulled away from the adjacent wall exposing it to the elements. The steel siding that was installed around the enclosure was also done without proper flashing. Because the homeowners waited nine months to contact Murphy after first noticing the gap, the insurance company denied their insurance claim. But based on the extent of the wood rot, the solarium structure probably had been leaking for decades.

Improper flashing around windows
Discoloration in ceiling a sure sign of water intrusion

The couple had used the sunny area off their master bedroom as a greenhouse. They had no idea it had a serious leak until they discovered mold on the garage wall below. The water damaged everything from studs to foundation block, which was crumbling in places.

Murphy Bros ended up replacing much of the framing below and around the area before installing new glass, drywall and siding.

Garage wall reveals major structural damage to wood and block

How Shall I Rot Thee, Let Me Count The Ways.

Veteran water intrusion specialist Alan Powell from Certified Moisture Testing knows it well. He uses electronic probes and hard-earned experience on a daily basis to find moisture.


“A study we did on 2,000 homes we tested suggests that up to 95% of all stucco homes built from the 1980's into the 2000's had some degree of structural rot damage due to moisture entering around windows, roof terminations, decks, grade, etc., “ he said. “Most of the issues were from reactionary building codes, lenient enforcement and improper construction practices at the time. When more stringent energy codes took effect and homes got tighter, wet wood never had time to dry before getting wet again.”


It’s not just stucco. Water intrusion can compromise any house regardless of the siding or roofing material. In fact, installing vinyl or metal siding over existing siding and wrapping old wood-frame windows and doors with cladding can conceal uncorrected structural problems and make them even harder to detect in the future. Here are some common causes:


Roofs – Leaks are most likely to develop around protrusions or along valleys and vertical planes. Faulty boots around plumbing vents, improper installation of vents and skylights, incorrect flashing against chimneys and vertical walls, inadequate ice and water membranes along valleys and eaves and shallow roofs, no kick outs where lower roofs terminate along siding. Leaks also come from warn or hail damaged roofing.


Windows and doors – Improper flashing and perimeter sealing and vapor barrier layering.


Decks – Improper ledger flashing where deck is attached to the house. Decking that is flush with doorway thresholds, and notched rail posts.


Stucco and brick-facing – Improper or missing vapor barrier and drainage between sheathing and masonry.


Poor Maintenance -- Deteriorated caulking around windows, doors, trim, and bathroom tile. Neglected wood siding, trim or decking that dries out, splits and bows. Clogged gutters that back up. Minor plumbing leaks left unattended.


Foundations/Drainage – Inadequate exposed foundation that causes excessive water to splash on siding or flood. Lack of positive slope away from house and gutters systems that manage runoff.


Condensation – Excessive trapped indoor moisture from inadequate ventilation or underutilized exhaust fans, improperly vented clothes dryers, un-insulated pipes, open crawl spaces, and incorrect vapor retarder placement.


Better Three Hours Too Soon Than A Minute Too Late

Murphy says clients often think they have just a little wood rot or moisture problem or want something remodeled and aren’t even aware there’s a problem until his team does a preliminary inspection and starts demolition.

Signs to look for:

  • Bubbling paint
  • Peeling finishes
  • Darkening surfaces or stains
  • Swelling siding

Powell agrees. “Most moisture intrusion cases are not known or seen,” he said. “The wall cavity is like a large sponge. It takes a lot of water to fill that sponge and be seen,” he said. “Watch for water entering around windows, condensation, musty smells, stains, doors and windows that no longer close, and breathing issues that seem to improve when on vacation.”

Choose Wisely

All three couples interviewed for this article agree that homeowners must choose contractors carefully, keep up with maintenance and, above all, pay attention to the first clue of wet or rotted wood, water stains or insects.

“My advice is if you have even the slightest inclination that something is wrong, don’t put it off. Have it checked out,” the Long Lake homeowner suggested.

Powell offered, “Hire contractors known for using best practices and best materials. They won't be the cheapest, but usually are the best.” He also recommended commissioning a qualified third-party inspector or engineer to advise during construction.

Hiring an experienced, licensed contractor who obtains a building permit and gets work inspected certainly improves your odds of avoiding water intrusion and wood rot problems, but Powell says don’t expect to hold the city inspector liable if a leak develops. Legally, city inspectors have no liability if they miss a code violation. Plus, keep in mind that codes set minimum performance standards, he said.


 “Fortunately, the whole industry has changed as a result of moisture intrusion. The building wrap is done differently with better materials. Window design failures have been fixed. Roof terminations have kick out flashing. But a home is only as water tight as the carpenter swinging the hammer chooses to make it,” Powell said.