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For those of us who have homes with basements, how to prevent water damage is a constant worry. One solution that a lot of experts believe will help remediate the problem is the installation of drain tile systems. But what are drain tiles? How effective are they? How much do they cost? In this short read, we’ll answer these questions and more, so you can make educated decisions about installing drain tile systems.
What is a drain tile system?
A drain tile system refers to a system designed to redirect excess water from the home’s basement or crawl space, and away from the home in general. While all homes may not need this system, you should definitely consider it if you live in an area that experiences heavy rainfall and snowfall.
That being said, a drain tile isn’t really a tile at all. Instead, it is a porous PVC pipe or flexible plastic pipe that is laid beneath the surface around a home’s foundation. The purpose of this system is to collect excess water before it enters the home and redirects it to be drained in a safer place.
If the home is on an incline, that safe place could be downhill. Keep in mind though that a minimum pitch of ¼ inch per foot must be maintained while laying the pipe down.
However, if your home isn’t up on a slope, the water will need to be redirected to a collection pit, from where it is directed out of the house by a sump pump.
Often, these outlets lead to an existing drainage system, while in other cases, the sum pump sends the water to an open ground from where it can drain into the soil or into nearby storm drains.
Drain tile systems are known by other names as well, including weeping tile, foundation drain, perforated drain, and perimeter drain. In agricultural and gardening parlance, it is commonly called a French drain.
Types of pipes used
There are types of pipes commonly used for drain tiles systems.
The first type of pipe is a rigid PVC pipe with holes on one side. This pipe is laid into the ground with the holes facing down. Water enters the pipe from underneath it. This type of pipe is used because it has a crush resistance of up to 3000 pounds. However, because of its rigid nature, you will need corner fittings to navigate it around the house. Expect to spend around $0.65 per foot on this pipe. You can purchase them in 10-foot lengths.
Flexible plastic pipe
The second choice for a drain pipe is a perforated flexible plastic pipe. The perforations allow water into the pipe, but keep large soil particles out. Alternatively, you can buy this pipe with a fabric sheath which will prevent even smaller soil particles out.
At $0.40 per foot, the unsheathed version of this pipe is cheaper than the PVC alternative. However, since plastic isn’t as durable as PVC, these pipes are more likely to be crushed by backfill.
Both PVC and flexible plastic pipes are available in sizes ranging from two inches to 18 inches in diameter. The standard size used in most cases is 4 inches.
There are two ways drain tile pipes can be laid: externally and internally. And while older homes can drain tile systems installed, it is easier to get the job time while the home is still under construction.
As the foundation of the building nears completion, a deep trench is dug alongside the footings on the exterior of the home. The pipe is then placed in the trench and covered with a minimum of ½ – ¾ inch washed gravel. This is done to avoid blockages that might put the system out of service.
A porous fabric like landscape matting is used to cover the gravel before layers of soil are added to bring it ground level.
While the same process of exterior drain tile installation can be followed on older homes, it involves digging up the foundation walls of the home and removing pathways, trees, and decking. It is an expensive and disruptive process that does not guarantee protection for more than 10 years.
The other potion is internal installation, which involves retrofitting the system in the basement. The first thing that needs to be done is for the basement to be completely stripped down and emptied. If the basement has been finished, flooring and sheetrock will need to be stripped out along the bottom of the walls. Any furniture and cabinets must also be removed. Then, cover everything in the room with a plastic sheet.
A jackhammer will be used to dig a perimeter trench and sump pit into the concrete foundation and the ground below it. The pipe is laid so the groundwater runs into the sump pit, from where it is discharged to the outside by the sump pump via a discharge pipe.
The cost of installing an external drain tile system for a new house, assuming all materials and labor will cost around $70 per foot will mean spending around $3,500 for 50 feet of drain tile. The same installation for an older home could cost between $25,000 and $50,000.
Internal drain tile systems are relatively inexpensive, costing around $4,500. However, actual costs will vary depending on basement access, size, and complexity.
Read more: Plumbing on an exterior wall
There are some hidden costs that you will need to consider as well while installing these drain systems. For example, if you need the water to be directed to another part of your property and not to an existing drain, you may need to spend an additional $3,500 on a dry well. If you’ve ripped up the basement floor for an internal installation, you will need to reinvest in basement waterproofing and flooring.
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