After you’ve completed Step 3 which is insulating your crawl space, the next step will be sealing everything off from the outside environment. For this to work properly, you need an airtight seal.
Step 4 – Sealing The Crawl Space
Before you can have a conditioned crawl space, everything must be sealed in the crawl space. That includes all foundation vents, windows and doors. So yes, I’m referring to both crawl spaces and basements here. The terminology differs from where ever you are in the country, the world. However, there’s clear differences between a crawl space and a basement. Typically, basements have windows and doors. Usually, crawl spaces do not, but every crawl space is different.
If you have doors, windows or vent, they must be completely sealed. No questions about it.
Sealing Your Vents
Although your foundation vents may close and open, this does very little to keep the outside environment out. If the outside environment can get in, your crawl space is not sealed as it needs to be. Due to this, all foundation vents must be completely sealed off from the exterior elements. Do keep in mind the building codes for your state as each state differs.
Sealing Your Doors
Just as you did with your foundation vents, the crawl space access door (if you have one) will need to be insulated also.
Pay Close Attention To Everything
Since every crawl space is different in one way or the other, we suggest that you pay attention to everything. Make sure everything is sealed up and no outside air is coming in to the crawl space.