Awareness of how water interacts with buildings will be:
Mold is easy to understand!
It needs moisture + food (organic matter) to grow.
As a general contractor, I often lament that our buildings are made of organic matter: Wood is, and always will be, mold food.
Keeping our buildings dry is a matter of saving both our health and property: Water truly is the destroyer of buildings.
Not because water dissolves the structure, but because water allows mold to grow.
The mold is what breaks down the structure.
But long before the structure is compromised, mold will make a building unhealthy to live in — and if you’re quite sensitive to mold, living in a so-called “sick building” can severely impact your life.
The good news: You don’t have to feel uncertain, afraid, or helpless when it comes to the health of your home.
Instead, I encourage you to become empowered — through awareness of your building! Know how it interacts with moisture, and know what to do about it.
Confusion disappears when we understand how buildings work.
There’s no reason you can’t become a top tier home inspector — for yourself.
This page is designed to get you there.
Inspect every inch of your home — looking for signs of moisture or water intrusion.
Become a Do-It-Yourself Building Inspector
You don’t need all the answers immediately, and being unsure about something is okay.
Instead, learn the process of inspection.
Where to Begin: Inside or Outside?
It doesn’t matter whether you begin inside or outside — but I like to start outside.
The first thing I look for is the “exterior grade.” Does the ground slope away from the house?
We’ll explain this in the next sections.
As you look at a building, use your imagination. How does water interact with this structure?
- Where does water come from (rain, ground, plumbing pipes)?
- Where does it go?
- Can moisture enter the house?
- Can moisture leave the house?
It can be shocking how easily water finds its way into buildings.
Buildings require drainage away from the foundation.
This is a non-negotiable matter. Water that stands around — or pools up against — a building will always find a way inside.
Not only is this structurally unsafe, it leads to moisture in the house. Moisture wicks up through the foundation walls, and mold develops inside walls and flooring. The water has to go somewhere, so humidity rises inside, feeding mold everywhere.
Instead, water should be directed far away from buildings, and not be allowed to sink near the foundation.
Most local building codes require one foot for every ten feet — and that should be treated as a bare minimum.
Here’s what a proper slope should look like.
Example: Proper Slope Away From House
Notice the foundation is “above grade” — meaning, it’s above the ground level.
Because the foundation is higher than the ground, the builder can “back fill” dirt up against the foundation.
This creates a slope away from the house, allowing water to safely go somewhere else (not the house).
If the foundation is not built high enough above the ground (“grade”), water will stay near the house and sink into the soil, close to the foundation.
Example: Foundation Installed Too Low
Water that sinks next to the foundation will spread out, and find its way into the house.
Because the foundation is the only part of the house that can be in contact with soil, installing a foundation too low means that top soil cannot be added to create a slope — there simply isn’t room.
But there’s another reason it’s so important to set the foundation above the grade…
Buildings tend to settle — into the earth.
Over time, this can create a slope toward the house, causing water to pool against the house.
Example: House Settles Into Ground
This is a very precarious scenario. Water will find its way inside — quickly — when this is happening.
If there’s a basement, it will be constantly leaky, damp, and humid — and almost certainly moldy. The humidity will rise up into the house above.
Driveways must be sloped away from the house too. If the house isn’t set high enough, the proper slope on the driveway will not be possible.
Homes On a Slope
Homes that are built on a slope are particularly at risk.
Water will always flow downhill, and without wise engineering, the water will pool up on — and inside — the house.
To solve this, homes on a sloping grade should be built:
- High enough that the foundation will be completely above the grade at the highest point of the house
- With room to create a downward slope on both sides (toward a drain on the high side)
When the slope is steep and high enough, a retaining wall will be required to achieve proper slope.
If the slope continues on both sides of the house, the foundation will need to be quite tall.
All of the rules still apply — and are all the more important — when basements are a factor.
The foundation must be set high enough that the first floor is equally as high as it would be without a basement. The ground must slope away from the house on all sides.
It’s easy to imagine how disastrous water intrusion can be when basements are not protected by a proper slope away from the house.
Basements must be fully waterproofed, though this is difficult to observe after construction has ended.
Gutters are essential to keep water away from the foundation.
Even with a proper slope, falling water (from a roof) will erode the grade in no time, and create a pocket for water to pool against the house.
Downspouts should empty onto a splash block, not the ground. A splash block distributes water further from the house, preventing similar erosion pockets where water can pool up.
Roofs must be completely watertight — no exceptions. Any water through the roof means damage and mold, and it doesn’t have to take very long.
Even slightly loose shingles can let water into the building.
Nothing should ever penetrate shingles. Creating a direct hole through the roof — by nailing, screwing, or stapling anything on top of the roof — will cause a leak. All nails/screws must be covered by a shingle above it.