hello All,
When I built my cottage with a crawl space, I dug couple of feet to get to the rock beneath, and then built my footing resting on the rock.
Even though the land slopes pretty well (I have 3 feet high foundation in the front and 5 feet in the back) I did not envision installing a drain pipe within the footing. Now while trying to solve the water issue accumulating in the crawl space by installing a french drain inside the parameter of the foundation, my father called me up and suggested that I drill through the FOOTING (which is 16 inches wide and 8 inches high) and install a drain pipe instead of installing a french drain and a pump. However, I am very leery to punch a whole in the footing.
Anyone did similar thing? any opinion on whether it is safe to drill through the footing for an inch and a half pipe?
Thanks
Sharbin
I would be tempted to place it under the footing. Depending on the size pipe you will do less damage than causing a weak spot in the footing. Make sure you use Sch 40 or 80 so that he settling (if any) does not crush the pipe. !-1/2" pipe is not much of a drain. I would increase to at least 2" or 3". Is there any reason that you do not run the french drain on the exterior of the foundation at the footer? Unless you have a spring the exterior should prevent surface water from entering the crawlspace.
I already have a French drain on the outside parameter of the footing. I am assuming that the water passes through cracks in the rock formation beneath (mind I cannot confirm this as I have soil in the crawl space).
Since the footer is standing on a rock, I am not attempting to drill through the rock, rather through the footing about 3 inches from the bottom so that to install the pipe in an angle.
I've put alot of sleeves in footing both before and after the footing was poured with no issues. Most inspectors I've dealt with didn't have any concerns, a few ask me to seal the area around the pipe with spray foam. I kind of find it hard to believe you could hurt anything other than exposing some re bar. When you think about the amount of concrete before and after in your footing it is a very small area you'll be disturbing how ever if it was sitting in a area prone to foundation problems it may be asking for trouble but built on rock is about as good as it gets. I also would go with sch 40, 3"-4"
In chapter 26 of the IRC,
Section P2603.5 says that a pipe passing under a footing or through a foundation wall requires a sleeve or relieving arch. What they are looking for is a bit of room for movement. If you bore through the existing footing you'll probably hit some rebar. Being on solid rock I don't think you have any worries about weakening the structure.
thanks guys for the feedback.
I forgot to mention that the footing where I will be drilling a hole is on the non-bearing side of the cottage, i.e. the gable side.
How does the water get inside the house footprint? Does it seep year round or after rain? If it is from rainwater then it is generally accepted that it is better to keep water out of the building footprint, rather than trying to remove afterwards. Properly installed & functioning gutters & downspouts help tremendously in this regard, and the water must exit any subsurface drains a distance downhill from the structure. Likewise, contouring the land adjacent to the house (like a wide grassy swale) so that any surface water is diverted around the structure well before it can reach the footprint helps much.