Internal Drainage Systems: Different than Waterproofing Systems
There are systems which manage the water once it has entered into a crawlspace or basement (home). Sometimes these systems are incorrectly referred to, or sold as, waterproofing systems. Generally, the system will have a series of drains and/or pipe located in the interior space and placed adjacent the foundation wall. More often than not the drain pipe will flow to a sump pump, which in turn pumps the water collected out of crawlspace or basement and into the yard. These systems are sometimes required due to limited accessibility of a site, or sites which do not have terrain that would support an exterior drainage correction. The percentage of homes requiring such systems, though, is quite low. In our opinion, such systems have major flaws when used improperly. In the next series of posts, we will explore the pros and cons of these systems.
The Pros and Cons of Internal Drainage Systems
1) They do not aid in prevention of the excess water entering the home; exactly the opposite occurs. These systems invite the water to flow under the footing and usually create a path of least resistance. After several years, foundation failure may occur in the direct vicinity of the drains, as water will take the path of that least resistance, flowing under and undermining the footing.
2) Block is porous and, to a lesser extent, so is concrete. By allowing the water to continue to flow against the exterior wall continued damage of the block and concrete footer(s) is still occurring! But, now that such damage is “out of sight” it likely won’t be detected for many years. Typically, once the damage is detected, it is by failure of the foundation or foundation walls.
3) For these internal systems to function correctly, especially in crawlspaces, water must build up in the pipe before flow to the sump pump occurs. This means that sometimes the water never makes it to the pump. So, the water is, again, sitting in the crawl space.
4) Internal french drainage systems typically require a great deal of water to build up in the drainage ditch, and then into the drain pipe, before it begins functioning. As discussed previously, this means that the water never actually exits your basement or crawlspace. The photo to the right shows a cutoff french drain system. As you can see, unless water migrates into the pipe from above, it would take approximately 5 inches of water to build up in the ditch and then enter the pipe. While this drainage system is fine for outdoors, and typically solves the majority of exterior water issues, you can plainly see that the ditch will continue to hold water, which remains in your crawlspace or basement.
5) All sump pump housings (a.k.a. basin, pit, or even drywell) must have a few to several gallons of water in them prior to the pump switching on. If the pump doesn’t switch on, the water sits in the collection cistern where the pump is located, which is, again, in/under your home.
6) All sump pumps fail. While many sump pumps have good warranties, this does not mean they will not fail. And, when do they fail? When you need them to be working! Many times this is when a power failure occurs. Most installers, including GROUT TECH, offer systems with redundant pumps (2 pumps in one housing) so that a second pump will kick in should the first fail. We also offer systems with battery backups should power failure occur. Naturally, these system get more expensive as you add options.
7) YOU are responsible for maintenance of the system, and checking monthly to determine if it is functioning. In most crawlspaces, accessibility to the pump is difficult. At the least, entering crawlspaces is not a pleasant task. Once a sump pump system is installed, though, it will be your responsibility to maintain it. Or the installing company will check it monthly for a fee. Failure of the pump due to lack of proper maintenance typically voids any warranties issued.
8) The upside of these systems is they are usually less expensive than actual corrections to the problem(s). Also, as we stated earlier, there are times when one will have to employ such systems due to the terrain around the home. Those are the only “pros” we can think of for these systems.
As a result of the above factors, GROUT TECH considers all available options for helping to cease or deter the water on the exterior of homes. Many options are available. On and directly adjacent the home you have exterior waterproofing and new drainage being installed (photos here). Away from the home you can simply improve the exterior drainage. Whatever option you choose, keep in mind that your primary goal should be to keep water from getting to your home. No matter what you choose to do to manage the water after it enters your basement or crawl space, and no matter what type of material is used to cover the ground or basement floor and walls so that you cannot see it, damage is still occurring to your home. The old adage, “Out of sight; out of mind,” completely applies in these situations because you don’t see the damage anymore, you naturally do not think it is occurring…until structural issues develop.