Looking to do a DIY crawl space inspection? Hopefully this will help. Maybe you are one of the lucky homeowners with a three foot tall (or taller) crawl space and you've decided you're up for the task. Or perhaps you are one of the few homeowners willing to crawl around under your house. The hard part is out of the way then, you've already summoned the courage to enter the dark unknown! Now you need to know what to look for, since you don't want your efforts to be in vain. Let's go over all the areas you want to inspect, including; HVAC, plumbing, water intrusion, and moisture control.
A couple small things to look for before we get to the meat of the inspection. First is a good crawl space door. One that's not rusted out, held closed by random objects, has gaping holes in it, or is missing entirely. This will keep those unwanted pests from trying to make a home under your home. Second is checking to make sure your dryer vent is properly vented to the outside. I see it more often than you would think, where the dryer vent has busted and lint starts dumping into the crawl space. This is a fire hazard, so double check that it is properly vented outside.
When Inspecting your HVAC system in your crawl space, you'll want to check all vent lines to make sure none have been disconnected, both at the main supply line and where it connects to the floor, leading to potential inefficiency in your HVAC system. Also, check vent lines have not been crushed anywhere. Lastly, you'll want to make sure the insulation around your duct work- which is what helps to keep condensation at bay- is in good condition, not hanging down or missing in areas.
There's not a whole lot to look for when your inspecting the plumbing system in your crawl space. But, you can make sure all your lines are supported properly, keeping tension off the joints which can lead to leaks in the future. Also, inspecting for any current leaks would obviously be a good idea. Just visually check all joints for signs of a leak and also any horizontal lines for water droplets along the pipe could be signs of a leak. You can also find your water meter and watch it while no water is being used inside, if the meter is running you have a leak somewhere.
If you look into your crawl space and see your reflection, you just may have a water intrusion issue. Standing water can be the cause of many outside drainage issues or a plumbing leak. Either way, it will need to be repaired to prevent further damage. Other ways to tell if you've had standing water in your crawl space before are water lines along the foundation walls or if you have a lot of dirt on top of your plastic barrier where the dirt had mixed with the water and when it dried out the dirt was left on top. These are usually found in the lowest point of the crawl space. Lastly, if you see a lot of salt deposit marks all along your perimeter walls than you have water seeping through the foundation.
Assuming you don't have a relative humidity meter, you can still visually tell if you have moisture issues if you have any of the following; bat insulation hanging down or laying on the floor, lots of condensation forming on the HVAC duct work, and mold growth on your floor joists, sub floor, or support beams. Anything above 60% humidity in a crawl space can support mold growth. You also want to make sure your vapor barrier is intact, not bunched up exposing dirt, not so old its chipping and flaking, or simply that it actually exists. A vapor barrier is going to be your first line of defense against moisture within your crawl space.
Now that you have a better idea on what your looking for while your crawling around in your crawl space, hopefully you'll have a DIY inspection that lets you get in and out of there. Which brings me to another point, make sure you have a BRIGHT flashlight when you get under there, I'd say nothing under 500 lumens, you want to be able to see what your inspecting. You may even want to make yourself a little checklist to bring with you so you don't forget anything. Good luck! And as always if you get overwhelmed, contact a local professional.