Does your basement leak? Do you think that your weeping tile is plugged and needs to be replaced? Then this post is for you.
In this post:
Fortunately you are reading this post because, here, we provide you with the scientifically correct information you need to make well informed decisions with respect to new weeping tile installation. The first step is to understand why it is installed and how it works.
Typical weeping tile installation around new construction
|Weeping tile installed along footing of new foundation|
Why weeping tile is installed around your foundation
Weeping tile has been installed to drain water that pools at the base of foundations for the last 80 years or so. Weeping tile was so-named because the original systems consisted of sections of terra cotta clay pipe that would allow water to weep into them and, once water entered the pipe, the weeping tile system drained the water away. Below are pictures of this obsolete "weeping" tile that was used extensively during the 1950's and remains very prevalent today:
Original clay weeping tile installation along foundation
Weeping tile contamination can vary significantly
A weeping tile system is really a simple drainage system installed around your home, next to the exterior side of the footing which is at the base of your foundation walls. The purpose of weeping tile, also referred to as drainage tile or drain tile, is to provide a drainage point that will drain water, that has accumulated at the base of the foundation (the footing), to the storm sewer beneath your street or into a sump pump liner installed under your basement floor.
Without this ability to drain water that has pooled or accumulated at the base of your foundation, your basement walls would effectively sit in a puddle of water for its entire life (depending on the height of the water table of course). Pooling of water at the base of your foundation is a situation to be avoided because, given the porosity of concrete, whether poured concrete, concrete block or cinderblock, or mortar binding blocks or stone, the mortar joints and concrete in general will absorb water. The pooled water will naturally wick through the concrete and the mortar joints and cause saturation of this concrete and/or mortar which will then cause the concrete and mortar to soften and weaken with each passing year; thereby gradually weakening and damaging your foundation walls.
Is it necessary to install new weeping tile?
Installing brand-new weeping tile around the footing of your home will certainly enhance footing drainage; however, most of the time homeowners agree to have this expensive basement waterproofing work done and end up wasting alot of money because they didn’t actually have a drainage problem to remedy. In actual fact, many basement leaks have little to do with the drainage efficiency of installed weeping tile.
To be sure that you don't spend more money than you have to, read our blog post entitled: You have a leaking basement, is it time to replace the weeping tile?
Does replacing weeping tile guarantee a dry basement?
It is crucial to understand that, with or without new weeping tile, a leaking basement will most likely continue to leak; this is because most basement leaks are not really the result of faulty or clogged weeping tile systems. In fact, many new homes with brand new foundations and brand new weeping tile installations still have basement leaks. While this fact may seem illogical at first, further logical examination of this statement will prove that it is accurate. Read more
Why basements leak
The following three illustrations depict a typical weeping tile installation at the footing of a poured concrete foundation wall, as well as typical basement leaks for poured concrete and concrete block / cinderblock foundations.
Typical installation of weeping tile
Concrete block foundation leaks
Poured concrete foundation leaks
Water that leaks into a basement through a foundation wall, is, in fact, entering through voids and cracks in those walls.
It is the protection against water ingress through these voids and cracks that ultimately keeps water from leaking through your basement walls. This protection against leaks through voids and cracks is the job of the foundation waterproofing product (coating) applied onto the exterior surface of your foundation wall. The installation of new weeping tile enhances your foundation's ability to drain away accumulated water present at the base of the foundation. However, efficient weeping tile drainage helps reduce the amount of water pressure against your foundation and therefore reduces the frequency and amount of water that will leak through the foundation walls.
In new home construction, poured concrete and cinderblock, or concrete block, walls are waterproofed using an application of sprayed-on tar and sometimes air-gap membrane (the purpose of which is solely damp proofing) is also installed.
|Foundation with weeping tile installed at footing and air gap membrane installed|
Even though a brand new foundation has been waterproofed with tar, which is usually applied as thin as paint, once a crack develops, the thin tar application doesn’t stretch enough to accommodate the growth of the crack. As a result, new cracks are not actually waterproofed because there is now an unprotected gap in the foundation. Installed air-gap membrane doesn’t help because the purpose of this membrane is to provide damp proofing; specifically for the purpose of keeping wet mud from being in constant contact with your foundation walls.
Notwithstanding the presence of perfectly installed and perfectly clear weeping tile, there remains significant hydrostatic pressure against your foundation, especially where clay soils are involved (this applies to most areas in the GTA with the exception of areas closest to Lake Ontario). If there is no barrier preventing this pressure from causing water to enter a foundation crack or void, then water will flow through your foundation walls and result in a basement leak. If the soil retains so much water which does not reach the weeping tile, how much added value is there in replacing weeping tile?
Weeping tile installation and exterior foundation wall waterproofing
When waterproofing your exterior foundation walls it is necessary to excavate those walls down to the footing. With the walls fully exposed, it would make no sense to forego brand new weeping tile installation, if only to replace partially blocked weeping tile along the area being excavated. If excavation is being done, then you may as well replace the weeping tile along the excavated area.
The gravel layer installed around weeping tile
Before you agree to spend thousands of dollars to excavate your foundation and install new weeping tile, whether along one section of the foundation, or for the entire home, you should know that your current weeping tile does have secondary drainage. This secondary drainage is provided by a gravel layer that surrounds the weeping tile; the current building code calls for 2 ft³ of gravel per linear foot of weeping tile. Because your weeping tile system has help in draining the water pooled around your home’s footing, a new weeping tile installation may actually provide little enhancement to the current drainage efficiency of your existing weeping tile system. Below is a picture of the gravel layer installed for a newly constructed home.
|Window well drains are installed connected to the weeping tile during construction|
Regrettably, many contractors, including waterproofing contractors, and particularly the average waterproofing company employee, do not understand the science behind weeping tile installation; therefore, they truly believe that installing new weeping tile will solve any leaking or wet basement problem.
Consumers must also keep in mind that excavating and waterproofing a foundation, which should always include new weeping tile installation, typically costs thousands of dollars. Therefore, the profit margin associated with excavation and waterproofing activities is significant. This is one major reason why exterior excavation and waterproofing is typically proposed, to most homeowners that have requested an estimate, for resolving most basement leaks.
Want to learn more? Read our companion blog post: Weeping tile system - The essentials
The installation of new weeping tile is not necessarily the ultimate solution for preventing and stopping basement leaks. Other less expensive options are available to you such as internal de-watering / internal perimeter drain installation and many others. For more information click on the following hyperlink for comprehensive information on available basement waterproofing methods:
Know your options and, if you are so inclined, you decide what waterproofing solution you will choose. Surely you don’t want to be bullied or intimidated into accepting a basement waterproofing solution you don’t need or really can't afford.