Crawl Space Drain Implementation

[u/thebuchananball_1]

I live in Traverse City, MI (climate zone 6A) and just bought a home in July. We have been having musty smells come up out of the vents, particularly after rain events, and the Crawlspace is pretty damp regularly. There is a vapor barrier installed below the floor joists, coving the insulation in between. I am wanting to remove this and instead insulate the foundation walls and encapsulate the Crawlspace.

While researching footer drain tile systems, it seems the recommendation is to place the drain tile right next to the footer. In my situation, the floor of the Crawlspace is below the bottom of the footer. I had a well-known Crawlspace repair company come and inspect it, and their recommendation was to place the drain tile 5ft away from the foundation walls, toward the center of the Crawlspace.

My question is: would it make more sense to place the drain tile 5ft away from the foundation, or to instead place it next to the footer and to add fill dirt or gravel to raise the height of the Crawlspace floor to be level with the top of the footer?

Thanks

[u/cagernist]

Not really building science, but a few points:

• Look up angle of repose. if you say the soil is below the footings (pics unclear), it needs to be at least a 45d angle from the bottom edge, compacted.
• An interior drain system is perfect for high water tables, but is really extra precaution to a proper exterior footing drain tile. Realize ground water will still be against your walls until the water table rises above the bottom of footing, where then an interior pipe can collect it. So moisture still comes through the CMU, and the joints will deteriorate long term (seeing how builders typically do not damproof crawls, and if they do they probably wouldn't choose waterproofing).
• So besides reviewing downspouts and grading, I always recommend with crawl spaces that exterior footing drain tiles are added along with proper waterroofing. Midwest crawls are usually a 5 or 7 block high, so it can even be hand dug in stages, easily DIYed. An interior pipe loop can still be added with this, which can also be used for radon as an option.
• Especially since you want to insulate the walls, consider the above point as you don't want moisture coming through.
• For "encapsulating" the crawl space, rather than going by what those companies push on you and hearing the point of view of homeowners who spent a dozen of thousands with them because they have no knowledge of it, read code yourself on how to make an unvented crawl space, IRC Section R408.3.

[u/YYCMTB68]

How big is your house? Any floor plans or sketches you can share?