Water is one of the most important things I look for during a home inspection.
After inspecting homes throughout New Jersey for more than 24 years, I have seen how much damage can begin with something that initially appears relatively minor. A missing gutter, poor grading, a short downspout, deteriorated exterior sealant, or improperly directed roof runoff may not look like a major concern on a dry day. Over time, however, these conditions can contribute to basement water entry, damaged siding and trim, wood deterioration, mold growth, and other moisture-related problems.
When I inspect a home, I am not only looking for water that is entering the building at that particular moment. I am looking at how the property manages water as a whole.
One of the most important questions is very simple:
When it rains, where does the water go?
Water Management Starts at the Roof
The roof is designed to shed water, but getting water off the roof is only the beginning. That water still has to be collected and directed to an appropriate location.
During a heavy rain, a roof can collect a tremendous amount of water. Gutters and downspouts are intended to control that runoff and move it away from the home.
Missing or damaged gutters can allow water to fall directly alongside the foundation. Clogged gutters may overflow. Improperly pitched gutters may hold water rather than drain properly.
Downspouts are equally important.
I frequently find downspouts that terminate immediately alongside the foundation. The gutter may be doing its job perfectly, but the system is still depositing all of that collected roof water at one of the worst possible locations.
Roof drainage should be directed away from the foundation to an appropriate discharge location.
Roof Design Can Concentrate Large Amounts of Water
Some roof configurations deserve additional attention because of the amount of water they can concentrate in a relatively small area.
Roof valleys are a good example.
A valley is formed where two roof slopes meet. Instead of receiving runoff from one section of roof, the valley collects water from both adjoining roof surfaces. If that concentrated runoff is discharged onto siding, stone veneer, trim, or directly alongside the foundation, moisture problems can develop.
The same concern can occur around dormers, roof-to-wall intersections, architectural projections, additions, and other complicated roof configurations.
This is why I look beyond whether the shingles themselves appear serviceable. The path the water takes after leaving the roof is also important.
What Home Inspectors Look for When Inspecting a Roof
Gutters and Downspouts Are More Important Than They Look
Gutters are not particularly complicated components, but they play an important role in protecting a home.
During an inspection, I look for missing sections, leakage, deterioration, improper pitch, loose attachments, overflowing conditions, and downspouts that are not properly connected.
I also look at where the downspouts terminate.
Some homes have underground drainage systems that receive the downspouts. These systems can work very well, but the underground portion generally cannot be fully inspected during a standard visual home inspection. Its condition and ultimate discharge location may not be known.
Older underground piping can become clogged, crushed, disconnected, or damaged by roots.
If there is uncertainty about an underground drainage system, its condition and discharge location may need to be confirmed.
Grading Is the Next Part of the System
Once water reaches the ground, the grading around the home becomes important.
The ground should generally encourage surface water to move away from the foundation rather than toward it.
I commonly find low areas alongside foundations, settled soil, relatively flat grading, and landscaping configurations that can trap water against the house.
None of these conditions automatically means that a basement is going to flood. They do, however, increase the amount of water that can remain near the foundation.
The concern becomes greater when several conditions are present at the same time. A home may have poor grading, missing gutters, and downspouts terminating next to the foundation. Each condition contributes additional water to the same area.
Improving these relatively simple exterior conditions can sometimes make a significant difference in controlling basement moisture.
Grading and Drainage Around a Home
Driveways, Walkways and Patios Can Affect Drainage Too
Drainage around a home is not limited to soil.
Driveways, patios, walkways, pool decks, and other hard surfaces can direct substantial amounts of water.
A patio pitched toward the house can direct water against the foundation. A settled walkway may create a low area where water collects. A driveway may channel runoff toward the garage or foundation.
These conditions are especially important because hard surfaces do not absorb water the way soil does. Water can move quickly across them and become concentrated at the building.
This is why I look at the property as a whole rather than examining individual components in isolation.
Exterior Walls Have to Manage Water
The exterior wall system is another part of the home’s water-management system.
Siding, trim, flashing, windows, doors, masonry, sealants, and other exterior components work together to help keep water out of the building.
Small defects can sometimes create surprisingly large problems.
Open joints around windows, deteriorated sealant, gaps in exterior trim, damaged siding, and improperly detailed transitions between different materials can allow water to enter behind the visible exterior surface.
Once water gets behind siding or trim, the resulting damage may remain concealed for a considerable period of time.
This is one reason exterior flashing is so important. Flashing should direct water back to the exterior rather than allowing it to enter the wall assembly.
Windows and Doors Need More Than Caulk
People sometimes think that sealing around a window simply means applying caulk around the outside.
A properly installed window is more complicated than that.
Windows and exterior doors should be integrated with the surrounding weather-resistant wall assembly so that water is directed away from the opening. Flashing, sealants, drainage provisions, and the exterior finish all play a role.
This becomes particularly important with newer additions and renovation work. If walls are still open during an inspection, it may be possible to see portions of the installation that will eventually be concealed by insulation and interior finishes.
Once construction is completed, much of that work can no longer be visually inspected.
Windows, Flashing and Exterior Water Penetration
Stone and Masonry Are Not Automatically Waterproof
Another misconception is that brick and stone prevent all water penetration.
Masonry exterior finishes can be very durable, but they are still part of a wall assembly that needs to manage moisture properly.
Water running repeatedly down masonry can result in staining, deterioration, freeze-thaw damage, and moisture reaching materials behind the visible surface.
When I see concentrated roof runoff flowing directly over stone or brick, I pay attention to where that water is coming from and where it ultimately goes.
Correcting the source of the water is generally more important than simply cleaning the staining that it leaves behind.
Basements Often Tell the Story
The basement can provide valuable information about how well a home has managed water over time.
I am looking for more than an active leak.
Water staining, efflorescence on foundation walls, deteriorated finishes, rusting components, damaged flooring, elevated moisture readings, musty odors, previous patching, and other conditions can provide clues about current or previous moisture.
The absence of visible water during an inspection does not establish that a basement has never experienced water entry.
Weather matters.
A home inspected after several weeks of dry weather may present very differently during several days of heavy rain or rapid snowmelt.
That is why inspection findings should be considered along with seller disclosures and the property’s exterior drainage conditions.
What Home Inspectors Look for in a Basement
Finished Basements Can Hide Important Information
Finished basements create another challenge.
Drywall, flooring, insulation, finished ceilings, built-in cabinets, and other finishes may conceal much of the foundation and structural framing.
There may be very little visible evidence of what is happening behind those materials.
This does not mean there is necessarily a hidden problem. It means exactly what it sounds like: those areas cannot be seen during a visual home inspection.
If I see warped flooring, moisture staining, a musty odor, elevated moisture readings, or other evidence of moisture in a finished basement, those observations become more important because so much of the underlying construction is concealed.
A home inspector should clearly explain these limitations rather than imply that concealed areas have been inspected.
Crawlspaces Need Water Management Too
Crawlspaces can experience many of the same moisture conditions as basements.
Poor exterior drainage can allow moisture to enter a crawlspace or increase moisture levels in the soil beneath the home.
Dirt-floor crawlspaces can also release substantial amounts of ground moisture into the space. Depending on the construction, a properly installed ground vapor barrier, appropriate drainage, and control of exterior water can help reduce moisture conditions.
Crawlspaces are also frequently difficult to access. Low clearance, insulation, ductwork, piping, stored materials, or other obstructions can limit how much of the area can be inspected.
Not All Attic Moisture Comes From a Roof Leak
When moisture or staining is discovered in an attic, it is easy to assume that the roof is leaking.
That is not always the case.
Attic moisture can also originate inside the home.
Bathroom exhaust fans that discharge into the attic are a common example. Warm, moisture-laden bathroom air entering a cold attic can contribute to condensation, staining, mold growth, and deterioration of the roof sheathing.
Air leakage from the living areas and inadequate attic ventilation can also contribute to moisture conditions.
Determining the source is important because repairing a roof will not correct an attic condensation problem caused by moisture coming from inside the home.
Why Bathroom Exhaust Fans Should Never Vent Into the Attic
Plumbing Leaks Can Look Like Exterior Water Entry
Interior plumbing is another potential source of moisture.
A stain on a basement ceiling could come from a plumbing fixture, drain line, water-supply pipe, heating pipe, condensation, or exterior water entry.
The location of the stain provides information, but it does not always identify the source.
Water can travel along framing, piping, ductwork, and other materials before becoming visible somewhere else.
A good inspection should distinguish between what was observed and what can actually be determined.
If the source cannot be established during the inspection, I believe it is better to say that than to guess.
Moisture Meters Are Useful, but They Do Not Tell the Entire Story
I use moisture-detection equipment during inspections when conditions warrant it.
A moisture meter can help identify elevated moisture in certain materials and can be very useful when investigating staining or suspected water entry.
It is still only one tool.
A moisture reading has to be considered along with the material being tested, surrounding conditions, visible evidence, recent weather, and the limitations of the instrument.
A dry reading on the day of the inspection does not prove that an area has never leaked.
Likewise, an elevated reading tells us that moisture may be present, but additional information may be needed to determine why.
Moisture and Mold Are Closely Connected
Moisture control is an important part of preventing mold growth.
When mold-like growth is observed, identifying and correcting the moisture condition is an important part of addressing the problem. Cleaning visible growth without correcting the underlying moisture source may allow the condition to return.
The source could be a leak, elevated humidity, condensation, inadequate ventilation, ground moisture, or another condition.
The important point is that mold and moisture should not be viewed as completely separate issues. Finding and controlling the moisture source is an important part of correcting the condition.
New Construction Is Not Exempt
Water-management problems are not limited to older homes.
I find drainage, flashing, roofing, siding, and moisture-related concerns in new construction and recently renovated homes as well.
Modern homes contain many different materials and building systems that have to be properly integrated. A beautiful exterior finish does not necessarily tell you what is happening behind it.
New construction also involves many different trades working on the same building. The roofer, siding contractor, window installer, mason, plumber, HVAC contractor, and other trades may all perform work that interacts with the building’s water-management system.
Small installation details matter.
This is one of the reasons I believe a brand-new home should still receive an independent home inspection.
Water Problems Are Often a Combination of Conditions
After inspecting thousands of homes, one thing becomes very clear: moisture problems are often not caused by one dramatic defect.
They are frequently the result of several smaller conditions working together.
A basement moisture problem may involve grading, gutters, downspouts, soil conditions, foundation openings, and exterior drainage.
A stain around a window might originate from the window, flashing, siding above it, an exterior trim joint, or roof runoff from somewhere higher on the building.
An attic stain might be associated with an old roof leak, a current roof leak, condensation, or improperly terminated exhaust ventilation.
Finding the stain is only the beginning.
The surrounding conditions have to make sense too.
A Home Inspection Is a Snapshot in Time
This is particularly important when discussing water.
A home inspection takes place during a limited period of time and under the weather conditions that exist on that particular day.
I cannot reproduce every weather condition the house will experience.
There may have been no rain for weeks before the inspection. The ground may be unusually dry. Snow may be covering portions of the property. Finished walls may conceal previous damage.
That is why I look for both active moisture and evidence of previous moisture conditions.
It is also why seller disclosures regarding previous roof leaks, basement water entry, drainage problems, plumbing leaks, and repairs can provide important additional information for a buyer.
What Homebuyers Should Take Away From This
Water management is not the most exciting part of buying a home, but it is one of the most important things to understand.
When you are looking at a house, pay attention to where water goes.
The roof, gutters, downspouts, grading, driveways, patios, exterior walls, windows, doors, foundation, basement, crawlspace, and attic should not be viewed as completely separate components. They are all part of the way the home manages water and moisture.
A home does not have to be perfect.
Finding drainage or moisture concerns also does not automatically mean that a house has a serious problem. Many conditions can be corrected with relatively straightforward improvements, particularly when they are identified early.
What matters is understanding the conditions before they lead to additional damage.
That is one of the purposes of a thorough home inspection: not simply identifying what is wrong on the day of the inspection, but helping the buyer understand the home, how its systems work together, and where corrective action can help protect it in the years ahead.
John Martino is a New Jersey Licensed Home Inspector and Board-Certified Master Inspector with LookSmart Home Inspections. John provides independent home inspections for buyers throughout Northern and Central New Jersey. His inspections focus on helping homebuyers understand the condition of the property, significant defects, safety concerns, and the home’s major systems before making one of life’s largest purchases.
John Martino | LookSmart Home Inspections
New Jersey Licensed Home Inspector – Board-Certified Master Inspector
Serving Northern & Central New Jersey