Why does my basement stink?

Recently Flooded Basement


Home inspections in Buffalo, Hamburg, Lancaster, Tonawanda and areas with older homes bring lots of surprises to a home inspector.  Most of these houses were built in the early to mid 1900’s, using building materials and techniques that were standard, or even cutting-edge for the time.  But the basements in these houses can be dark, dingy and stinky places.  

These dank basements often have what you may call a “mildewy” smell (Mold and mildew are not the same). What causes stinky basements in these houses, and how can you make them smell better?  Do houses with stinky basements present a danger to your family?  Is mold always to blame, or could there be another problem in the basement that your home inspector may find?  

Moisture is often the problem

I usually assess the basement or crawlspace (some houses have both) at the end of the home inspection in Buffalo, because they can be dirty places but also because they take the most time of any system in the home.  

The basement or crawlspace inspection always includes visible portions of the foundation, floor, plumbing, HVAC and other systems.  Several defects with these systems can cause a basement to have a nasty smell.

With only a couple exceptions, moisture leads to bad smells in the basement.  The home inspection report that my clients receive provides clear documentation when water or moisture infiltration is identified, but since a home inspection occurs during a single moment in time, these issues aren’t always seen.

We offer mold testing in Buffalo, Amherst, Hamburg and all of Western New York.  Our service includes water intrusion investigation, thermal imaging and visual identification of mold in your home.

Permeable Foundations allow water to enter the basement

Cinder Block Foundation with Mold Growth
permeable cinder block foundation

Poured concrete foundations were first used in Buffalo in the early 1900’s, and most homes that we inspect are built on this type of foundation.  

But, it’s not uncommon for us to find homes built with cinder block, concrete block, stone, or even wood foundations.  

A misconception is that cinder and concrete block foundations are made from the same material.  In fact, cinder blocks are made of an entirely different material from concrete.  Unless the foundation has special waterproofing treatment, cinder blocks can allow water to seep slowly through the foundation.  If the humidity level in the basement is high enough, mold might grow on the foundation.

Exposed Dirt Floor

It’s typical to see basement floors that are severely cracked or have large areas of exposed soil.  These exposed areas become damp, and if they don’t become channels for water then they at least have the effect of raising the humidity in the basement.  

The honest truth is that basements have only recently been built with the idea of comfort in mind.  Back in the day they were purely functional, and the thought of converting one into a man cave, lady lair or other awesome place just never crossed the minds of the homeowner or builder.

Water seeping up through floor
Exposed ground in basement, and failing casti iron drain piping

Exterior problems can cause damp basements

Our professional home inspection report includes an entire section that covers the exterior and ground of a home.  A focus of this part of our home inspection process is drainage.  If water from rain and snow is not properly moved away from the home’s foundation, then sooner or later water will penetrate the basement. 

What do we look for during the exterior home inspection in Buffalo and Western NY?

  • Are downspouts taking water away from the foundation by at least six feet?
  • Does the home have gutters everywhere that they can be installed?
  • Does the sump pump discharge well away from the foundation?
  • Do basement window wells have drains?
  • Is the lot that the home sits on graded to allow water to drain away?
  • Does the basement sump pump discharge far enough away from the home?
  • Are cracks visible in the foundation?

How can I make my basement dry?

This is a big topic, and is too much to cover here.  But, here are a few ideas to help you dry out the basement and get rid of the damp, dank, mildew stench:

  1. Professionally have any foundation cracks sealed
  2. Waterproof the exterior of the foundation wall if necessary
  3. Install french drains around the foundation footer that feed a sump pit
  4. Make sure you have a sump pit and sump pump
  5. Install a backup sump pump, one that uses either city water flow or battery power
  6. Install a water alarm to inform you via audible alert and mobile device if the sump pump fails, or if plumbing leaks occur
  7. Ensure that windows and doors are weather tight
  8. Make sure the basement floor is solid concrete from wall-to-wall
  9.  Install heating registers or other ventilation in the basement if necessary
  10. Consider using a dehumidifier in the basement, but make sure it is emptied regularly or drains directly to a sump pit or other appropriate location.  

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About the Author:

Bradley Beck

Bradley is owner of Alto Home Inspection, LLC.  He lives just south of Orchard Park, in Western New York’s Southtowns, and inspects homes throughout the Buffalo area, and is NY Licensed Home Inspector #16000086029, NY Certified Mold Assessor #MA01313.