New Jersey home inspectors should have an understanding of footing drains and why they fail. Footing drains are a primary cause of basement water infiltration problems in homes.
When a home is constructed, there are two things that help keep water out of the basement. A coating on the exterior of the basement walls called it damp proofing. And a proper drain around the bottom of the foundation called a footing drain. Footing drain failure is the most common cause of wet basements. When the footing drain fails the soil around the exterior of the home cannot drain properly when it becomes saturated. The pressure of the water in the soil around the exterior of the home creates hydrostatic pressure and pushes the water through the porous basement walls. The most common areas of this water penetration are through wall cracks and pipe penetrations as well as the joint between the footing in the wall. Also, water can enter through foundation walls that are porous. No foundation wall is impermeable to water.
A footing drain is a drain system installed around the exterior perimeter of the home at the base of the footings below ground when the home is constructed. The purpose of the drain is to prevent water from collecting close to the foundation walls where it can cause damage and enter the basement or crawl space. The drain if working correctly discharges this water away from the home to on appropriate location. Sometimes this location can be a dry well or a storm drain. A footing drain is typically composed of a perforated type of pipe installed in a layer of gravel that allows water to enter this pipe. The pipe is then properly pitched, and water is sent out to an appropriate point of discharge such as a dry well. The importance of a footing drain cannot be overstated because without a properly working footing drain basements and crawl spaces are subject to water infiltration and damage. However footing drains are sometimes not installed correctly and fail causing water infiltration to occur in the lower level of homes.
NJ Home Inspectors should be familiar with some problems that occur with footing drains:
- The discharge point or location that the drain empties into can be crushed or obstructed.
- The drains may not go anywhere and just discharge into the earth which is a significant issue because obstruction will quickly occur, and the drain will fail.
- The drains can have inadequate amounts of stone installed around them which leads to poor drainage and function.
- The drains below ground can settle shift or move and develop a belly making them ineffective at piping water away.
- A common source of failure is just simple obstruction from dirt entering the perforated piping system.
- Drains can easily be crushed or displaced by back fill when the home is constructed.
Having a footing drain failure can certainly lead to water entry into the basement. However, there are other things that contribute to water entering into the lower level as well. Soil around the foundation generally settles. Soil will settle especially after the first few years of being backfilled around the foundation. Few people if any actually regrade or build this area up properly to slope the soil away from the exterior foundation walls as required. Often mulch is used in this application however the mulch is porous and degrades and will not be effective even if built up and sloped away from the foundation walls to direct water away over the long term.
Hydrostatic pressure develops around the exterior foundation walls of the home. Hydrostatic pressure can be considered the weight of the water when it is at rest. The weight of the water around the exterior foundation walls actually causes pressure to build and causes foundation wall leakage. The higher the water is in a vertical column around the exterior of the home the more significant water pressure is. Take for example if there is a space or void in the soil outside of the foundation wall. This void gets filled with water during heavy rain. This will cause significant hydrostatic pressure to push the water into the basement or lower level of the home. The more water that rests around the exterior of the home without being directed away the greater the hydrostatic pressure is against the foundation walls and the more vulnerable the walls are to leakage.
New Jersey home inspectors should not recommend the replacement of footing drains. One method to remedy a basement water problem is to excavate around the exterior of the foundation walls and install a new footing drain if the drain has failed. This is an expensive and rarely a best practice method to cure a basement water problem. What you are essentially doing is replacing the same system with a similar system that will also fail down the road. Excavation around the exterior of the home is generally done at about 8 feet to the footings. The problem is where do you put all this excavated dirt for the time being? Excavation can actually cause damage to the foundation walls of the house. It is recommended that most basement water infiltration problems be remedied after the home is constructed by an interior method rather than an exterior drain system replacement. Also, everything as far as landscaping, sidewalks, decks and steps will also have to be replaced and this is at a very significant cost to the homeowner. Once again, the dirt has to be back filled into this large and deep trench and once again the dirt will settle over the first few years. So regrading is also a necessity if a exterior footing drain is replaced. This is a very costly and invasive undertaking to cure a basement water problem.
On the exterior of the home all downspouts should extend at least 6 feet away from the exterior foundation walls to properly carry water away. In some instances, the downspout discharge pipes are installed below ground which makes for a cleaner look however there are some problems with this configuration. The underground piping like any discharge piping has to have a pitch downward and away for them to work properly. It is sometimes challenging to properly pitch below ground discharge pipes properly. Often these below ground discharge pipes will become obstructed with leaves and debris from the gutters. So regular maintenance is going to be required to keep them free-flowing and unobstructed.
NJ home inspectors should understand the limitations of curtain drains. Sometimes contractors will recommend that curtain drains be installed in the backyard or the front yard. This is most usually recommended when the rear or front of the property has a slope that will direct water to the home. A curtain drain is simply a trench in the ground installed at a base of a hill or slope. A perforated pipe is installed underground, and crushed stone or gravel is installed under and around this piping in the trench. These drains are used to intercept or contain water flowing down a hill or a sloped lot. However, they should not be solely relied upon to keep water out of a basement. These drains are more successful at avoiding puddling or water retention in a yard however they have really limited capacity at keeping a basement or crawl space dry. They will be helpful to some extent, but it is highly likely that other corrections will also be required to keep water out of the lower level or basement.
Attempting to repair a basement water infiltration problem from the exterior can have limited usefulness but are likely to not be effective or desirable. New Jersey home inspectors should recommend fixing a basement or crawl space water infiltration problem from the interior rather than performing expensive corrections on the exterior of the home. Simple and straightforward steps can be taken to direct water away from the foundation that are cost-effective like extending downspouts and cleaning gutters and improving the grade. But when it comes to replacing a footing drain significant expense and invasive problems can take place. The process of de-watering a basement should take place on the inside rather than the exterior of the home.
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