Our home was built in 1941 with no basement, just a crawl space. Being a first-time homeowner, and being the neighbor of a frugal mind like Nick, I learned something valuable this past week:
Insulate your crawl space to block drafts and energy loss.
Since buying the house 2 years ago, we’ve noticed drafts coming from certain parts of the home, but we’ve focused on trying to block the air from within the home itself. However, the true problem was our crawl space vents. If you do not have a basement, you probably have noticed vents all around your home leading into the crawl space.
These vents have a single purpose: To allow humidity to escape from under your home.
Why would you need to vent the humidity under your home? Where does it even come from? Well, thanks for asking! Let me answer those questions for you!
Where does the humidity come from?
Unless you live in the Sahara, and never get a monsoon season, you need to worry about the water stored in the ground. On any spring, summer, or fall day, place an empty can, with both ends removed, on the ground. Cover that can with plastic securely. On a hot day, you’ll soon notice condensation forming on the underside of the plastic. It may take longer on a cooler day, but it’ll form. What does this tell you?
It tells you that the ground is always releasing water into the air. There’s physics or something behind it, and I’m sure there’s saturation levels involved, but rest-assured that this affects your crawl space. This leads us to our next question…
How does this affect me?
If you own a crawl space, and it is not properly vented, the moisture from the ground will go directly into your insulation and floorboards. Mold will form and your flooring will begin to rot. I don’t mean to scare you, but I hope you get the point that this moisture NEEDS TO GET OUT! (or at least be contained…read on)
What can I do to my crawl space?
Well, this answer comes in two parts.
First, make sure your vents are open in warm months. Oh, and make sure you have vents. We found that in our home the vents had metal flashing that was partially closed even in the summer months. For now, we kept them closed, and even insulated them, but I’ll get to that later.
In your case, make sure your vents are covered with mesh to prevent small intruders, and ensure there is proper flow on both the inside as well as the outside of the vent (i.e. make sure nothing is blocking either side).
Second, make sure your dirt is covered with heavy plastic. When we re-insulated our crawl space a few years ago, we laid down a good plastic covering, but not enough (we needed a break from the confined space). We need to add more, and that will happen this spring.
The images below illustrate the before and after of a properly covered crawl space. Note, though, that the ceiling is not yet insulated:
And now the last question:
But what about all that cold air in the winter???
Good question. There are vents that automatically close depending on the temperature (non-electric and electric). However, their seals may not be the tightest, and if these vents are on the windy side of your home, you may still feel a draft.
In our case, we decided to stuff R-13 insulation into plastic garbage bags, then into each vent. We noticed an IMMEDIATE and CONSIDERABLE change in temperature and draftiness (or lack of) inside our home. Nick did the same, and now notices his hardwood floors are not nearly as cold anymore.
However, we must make sure we remove the insulation before the beginning of spring so we can vent out the humidity from the crawl space.
If you have proper plastic covering on your crawl space floor, you can tend to wait longer to remove any covering or insulation from your crawl space, but it’s always good to protect yourself on all fronts.
- Make sure your crawl space is vented and the vents are not blocked
- Cover your crawl space floor with heavy plastic…all the way up the foundation walls
- Close or insulate the vents in the winter to save heating costs and you and your family from cold tootsies
- Remember to remove or unblock the vents before the temperature begins to stay above freezing for extended periods
- Be careful when working with fiberglass insulation. Wear goggles, a mask, and thick plastic or rubber gloves. Also, cover all exposed skin when working with it in your crawl space. Those little particles can lodge in your lungs and skin, and be very hard to remove
Photo Credit: Krystle.