French Drains

Can an interior French Drain System be installed in my basement without a sump pump?

Can French Drain piping discharge into my trap/sewer system?

In some homes there is a sewer trap below the basement floor. This is where your main sewer pipe leads to the exterior sewer system. In theory, a drain system can terminate into this trap area if the main sewer line cap is removed. BUT In most municipalities, it is illegal to discharge a French Drain System into a city sewer. Also, if the sewer backs up- your basement will flood with sewage. If your home is connected to a septic system discharging into your septic system could lead to a complete septic overload.

How should water seeping between my foundation walls and floor be repaired?

How should water seeping up through cracks in my basement floor be repaired?

Installing a perimeter French Drain System is the only correct repair for this situation. A French drain will keep the water table below your basement floor and prevent any further leaking. All French Drain piping should terminate into a sump pit and a quality sump pump should be installed

Can I seal up water that is entering my basement from between the floor and the foundation walls?

No. This problem can only be rectified with the installation of a French Drain System

Can I seal up water that is entering my basement through cracks in the floor?

No. This problem can only be rectified with the installation of a French Drain System

How can I stop water from getting under my basements floor/slab?

Can I stop water from getting under my basement floor/slab from the exterior?

You cannot prevent water from accumulating from under your basement floor! This is the level of the water in the ground in your area. (Known as a high water table) This water table is also at the same level under your neighbors basements. An exterior French Drain System will not prevent this from happening neither. If an exterior or interior drain system was installed, the water level under your basement floor would still be as high as the bottom of the drain system piping.

Do I need to install a French drain around the entire perimeter of my basement if water is seeping between my foundation wall and floor along 1 wall only?

A French Drain System can be installed along 1 wall only-it can also be installed along 2 walls  or in a very small area of only 5ft if needed. Generally, if your basement is leaking along 3 walls, we recommend a full perimeter drain system at this point. French drain system pricing is by the linier foot. If a small system needs to be connected into an existing system, you might pay 3 times the amount per foot on a small job due to the additional set up and preparation time. Again, a partial drain system can be installed and we can always add on to it if needed in the future. Things to consider when requesting a partial perimeter drain system installation.

Are you going to finish off your basement? Installing a French Drain in a finished basement is more costly and more damaging to your basement. Installing these systems in an unfinished basement is much easier and less expensive.

Do I need to remove the wall or drywall in my basement prior to the installation of a French Drain System?

NO! In most cases we can install a drain system with all walls in place. It is recommended that all base moldings are removed prior to starting as the drywall at the base will incur minor damage. When reinstalling base moldings the damage will be covered over. However, some drywall areas above the base might take on minor damage during the installation process as some concrete floors are much more difficult to remove then others. We have installed complete drain systems in finished areas with literally no damage to drywall at all. Bottom line, you should be prepared for some minor spackling and paint after our work is completed. If a finished wall partition is built too far from the foundation, some drywall might need to be removed to complete a drain system.

If a French Drain System is installed along 1 wall only, will water be push to another section of the basement?

ABSOLUTLY NOT! French Drain Systems are also called pressure relief systems. Upon the installation of a full perimeter or partial perimeter drain system, the water pressure is being relieved in the areas the drain system has been installed. A partial perimeter system will not prevent the rest of your basement from leaking.

Should my French drain system be installed on the interior (under my basement floor) or on the exterior around the perimeter of my foundation?

On homes that are not under construction, it is always easier and less expensive to install an interior drain system.

If you are having a new home built and the building site is set up high and there is an option to run the drain system piping to a low area, then you can install an exterior system. We still recommend an interior sump pump for a backup.

Also visit our French Drain System page for the pros and cons of interior systems vs. exterior.

Which way should the holes in PVC piping be facing?

The holes in PVC piping should always be facing upward!!! This subject is not open for discussion!! The holes faced upward in the beginning of time and always will face upward. If you or your contractor think any differently-then YOU ARE WRONG!!! I have had a select few try to argue this point with me and Im done wasting my time. I have repaired many systems over, where the holes were facing downward.

Minerals, iron bacteria and silt will always settle to the bottom of the drain system trench. Why would you want to place the holes downward? O right, that’s what cleanouts are for.

NJ Basement Waterproofing drain systems do not need cleanouts. We will install them only upon request or if there is a high mineral content or iron bacteria present.

How deep should piping be installed on a French drain system?

Interior piping should be installed 8 to 10 inches below the top of basement floor

Exterior piping should always be installed 8 to 16 inches below the top of the basement floor. Surface drain piping or a pipe installed even 1 inch above the basement floor will not work.

Sump Pumps

Do I need a sump pump?

If you have flooding in your basement and the water is entering from under the foundations slab, you will need a sump pump. If you are considering a French Drain system installation, you will also need a sump pump to complete the job. Sump pumps can also be installed as insurance. This does not mean you will never have a flooding situation in your basement. It will only prevent the water from becoming much deeper than the floor surface.

What is a battery backup sump pump and do I need one?

If you have a consistent water table and often experience power failures, you will need a battery backup system. A battery backup unit runs on a 12 volt deep cycle marine battery. This is only installed as a secondary backup system and should never be installed as a primary source for discharge.  A battery backup system is specifically designed to work together with your primary AC pump. If the power to the primary pump fails or if the primary pump malfunctions, the battery backup system will take over. All battery backup systems are wired to a charger that is plugged into your homes AC power supply. When the primary pump fails or the power goes out the battery backup will be on a full charge and take over the job. The charging unit usually has an alarm that will sound to let you know the backup system has been activated. When purchasing a battery backup, be very cautious as the prices vary tremendously. It is important to purchase a quality unit that will handle a large volume of water. Power failures are quite popular during heavy rains and hurricanes. So a unit that pumps 119 gallons per hour (GPH) will probably not be sufficient. NJ Basement Waterproofing recommends a backup system that will pump a minimum of 1500 GPH.


What is a pressure relief system?

A pressure relief system is French drain piping installed under a basement floor/slab. When drainage piping is installed under a basement floor, it will relieve the water pressure from under the floor in a given area.

What is a water table or high water table?

A water table is the level of water in the ground. (This should not be confused with the water level in a deeper well known as the aquifer.) A water table can vary according to specific weather precipitation. During heavy rains and spring thaw, water tables will be high. During dry weather seasons, water tables will lower.

What causes unpleasant musky odors in a basement?

Unpleasant odors can come from several situations.

  • High humidity levels -Install a quality dehumidifier will take care of this situation.
  • An undetected foundation leak
  • A previous flood that was not dried completely
  • Mold
  • Finishing basement to create additional living space

What recommendations do you have as I am planning to finish my basement to create additional living space?

We urge you to do a complete inspection of your basement after a heavy rain or during the spring thaw. Many times we have been told by homeowners, they never had a basement leak until they finished off their basement. In most cases, the leak was always there but no one spent any time in the basement prior to converting it to living space- so the leak went undetected.

A basement is always prone to have some kind of leak. Even if it has a drain system that is 100% perfect, there are several flooding situations that can occur. Most basements have a hot water tank or heating system, and most plumbing pipes run through the basement ceiling. Anything can happen with these items that can flood your basement. 

When installing drywall, have your contractor keep it, a minimum of ½ inch off the basement concrete slab.  When base moldings are installed they can be placed right on the floor covering up the ½ inch space. Drywall is like a sponge and can absorb water 4Ft up the wall. Mold loves drywall and will grow very quickly on it. The base moldings do not absorb at the same rate as drywall and do not mold up as quickly.

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