Monday, March 10, 2014

Crawl Space Vents And Grading



Quick Question:
I am going to have my crawl space encapsulated soon. I am wondering about the outside of my crawl space vents. They are obviously going to be sealed from the inside. My question is if I can raise the outside grading level of my soil higher, which would cover up the crawl space vents.
The vent is no longer functional, but would that be against building code by any means? Would it be better for me to install vent wells, then build the grading higher?
My house sits pretty low, so that is why I am asking due to not having much height to work with.
Thanks everyone!

The vent(s) may no longer be functional, but covering them with dirt will invite mud and water infiltration to the crawlspace. You can remove the vents and install a concrete block in it's place, pointing it properly to prevent water seepage.
In your area, you may benefit from encapsulation. I am not a fan of it due to the fact that you have to condition the air in the crawl. Sort of pointless IMO. But others advocate it, so if the science is there for you, it is well. If you remove the vents, grade up over them, and the encapsulation doesn't work, you will not be able to retro the vents. Wells may not be such a bad idea, for future use, and to keep from having to remove the vents.

How is your crawl space going to be encapsulated? Down here it is often attached to the bottom of the joists, leaving the dirt floor and sides of the foundation exposed so the vents are still functional. Will your system be on the ground?

The encapsulation included 12mil vapor barrier covering the dirt floor and up 6 inches on the sides, then 8mil vapor barrier continuing up to the sill plate. The vents will be sealed off from the interior side using rigid foam with spray foam to seal the edges. A french perimeter drain will be running underneath the vapor barrier and ran to my sump pump. Lastly, a dehumidifier will be placed inside the conditioned area to help with moisture control.
I am now thinking of removing the grilles/vents...not installing a solid block and just using the crawl space vent covers. So, in essence, both sides of the open block will be sealed from inside and outside. Thus, I should be able to just build the grading up (covering the vent areas) and leave at least 2-2 1/2in from touching the vinyl siding. If, for some ungodly reason, I have wasted my money down the road...it will be much easier to simply remove the covers and install the vent grilles again.
I respect that not everyone agrees with encapsulation due to many variables and regions, or just simply not buying into it. I do believe this is the best shot I have to reducing the moisture and slight mold problem that I had down there.
I appreciate your guys responses on the matter!






Tags: crawl, space, vents, grading, crawl space, remove vents, sealed from, vapor barrier, build grading, crawl space vents, dirt floor, from inside, install vent