How To Relieve Hydrostatic Pressure In The Basement

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Dealing with problems like water buildup on your basement footings and foundations? As too much water pressure can create cracks on the walls and floors, you may be anxious about how to relieve hydrostatic pressure so as not to compromise the safety of your home. Worry no more! We did thorough research and here's what we found out.

Hydrostatic pressure happens when groundwater seeps through the cracks of the basement foundation. To mitigate the problem, you can do any of the following interior drainage methods:

  • Shallow depth method
  • Deep channel drainage

You can employ a professional to do the waterproofing and avoid further issues. Also, you should be aware if insurance covers the water seepage caused by hydrostatic pressure. Continue reading to learn about the hydrostatic pressure in basements.

A sump pump installed in a basement of a home with a water powered backup system. How To Relieve Hydrostatic Pressure In The Basement

Is Hydrostatic Pressure In Basements Bad?

According to Olshan, hydrostatic pressure happens when a constant force pushes water to the basement foundation. Basements are prone to high water pressure because these areas are partially or fully below the water table.

If your residence is on a floodplain, you won't have to worry. If not, you should prepare for any water intrusion in the basement. Your home is at risk if there is runoff toward the basement.

Most basements have concrete slab foundations. Be it known that concrete is porous, having a below-ground area is susceptible to water seepage. The soil around the basement gets saturated with water and might not carry the weight of groundwater.

Water weighs 60 pounds per cubic foot. If the water accumulated is 4 feet, there is a 240-pound pressure per square foot of the wall. In effect, the basement walls and floors will get a great impact.

The tell-tale signs of hydrostatic pressure damage in your basement include:

  • Molds and mildew growth
  • High humidity levels
  • Efflorescence on basement walls
  • Musty smells
  • Insect infestations
  • Buckling and cracking of walls

If the issue persists, the house can become unstable due to the weak basement foundations. The cracks on the floor will get bigger and make the walls collapse.

To reduce the damage, you should do some solutions to relieve hydrostatic pressure.

Relieving Basement Hydrostatic Pressure

An effective interior drainage system reduces hydrostatic pressure. The system removes the water accumulated at basement footings and foundations. It has four main parts, namely:

  • Drainage pipe
  • Drainage stone or tile like gravel
  • Concrete over the drainage stone
  • Discharge system (sump pump)

To combat hydrostatic pressure, you might as well implement any of the following methods:

1. Shallow Depth Method

A sump pump in a home basement-plumbing repair

In this method, you will need to install a rectangular channel along the foundation perimeter. It is on top of the footing and around 2-4 inches under the basement floor.

The system works by collecting water from a gap where the wall and floor meet. Then, the sump pump installed discharges the water out of the basement.

2. Deep Channel Drainage System

An open french drain pit and sump pump basin prior to being filled with stones and covered with concrete.

This process is identical to the first method because you also install the system around the foundation perimeter. The difference is that you need to remove about 12 to 18 inches of the concrete slab and subsoil on the footings.

Parallel to the footing, the drain tile with washed gravel connects a collection tank and the sump pump. The method will also be efficient if you seal the pipes. By doing so, you prevent moisture from escaping the pump basin.

Other ways to reduce the hydrostatic pressure include:

  • Regrading the ground to make sure that it is not sloping downward to the basement
  • Keeping the position of gutters and downspouts away from the basement foundation  
  • Sealing off cracks on basement walls and floors as early as possible
  • Letting professionals repair damaged foundations  
  • Using a basement waterproofing system

You can reduce hydrostatic pressure to the greatest extent with these measures. It is best to combine available basement waterproofing methods to manage the problem.

If you do not have the expertise to install the system, your basement contractor can help.

Will Just A Sump Pump Relieve Hydrostatic Pressure?

sump pump inside a collection tank with water

For both methods mentioned above, the sump pump is an essential feature.

A sump pump will work best if the location is at the most central part of the basement floor. It effectively equalizes the hydrostatic pressure on the foundations. You also have to do regular maintenance for the pump.

Yet, a sump pump alone will not work well without other tools. You must remember that every part of the system is vital to create an effective solution against hydrostatic pressure. The sheet drains, perforated pipes, drain tiles, and similar components work best. 

You need a backup system to keep the pump working during power outages. A 12-volt deep cycle marine battery is a common backup for the sump pump. Another option is to use a water-powered pump as a secondary pump. You can use the municipal water pressure that seldom has interruptions.

Even if the pump is an integral part of an interior drainage system, it also has disadvantages you will find as follows:

  • It allows another way for water to enter the basement.
  • The dampness can cause mold growth.
  • There can be corrosion on the pump that can cause concrete spalling.
  • If the sump pump fails, it can cause more cracks and weaken the foundation.

So, it is best to use the sump pump with other integral components of the basement drainage system.

Read through a related post: Can I Drain Basement Dehumidifier To Sump Pump [And How To].

How Much Does It Cost To Fix Basement Hydrostatic Pressure?

You can prepare a budget of around $500 to $10,000 for an interior drainage system with a sump pump. You also have to account for the perimeter work, which will cost about $50 to $100 per linear foot. Labor costs will depend on the services and expertise of your contractor.

Here are other expenses you will incur:

  • Installing the French drain/weeping tile/drain tile - costs around $50-60 per linear foot.
  • Sump pump costs - cost between $700-1,600.
  • Sealing of walls and floor.
  • Repair of cracked foundations.
  • Excavation and pouring of new concrete for the perimeter.

The more extensive repairs, sealing, and excavation to do, you might spend more.

Does Home Insurance Cover Hydrostatic Pressure?

Some home insurance policies will not cover groundwater seepage caused by hydrostatic pressure. But if you can pay for higher premiums, you can get additional coverage for damages. To be sure, you can ask your insurance provider about the specific conditions of the policy.

If you want to file a claim, you should prove to your insurance provider that you have taken measures to prevent water damage. Make sure to keep evidence of the water damage in the basement. Also, remember to report the damage to the insurance provider as soon as possible.

If you paid for flood insurance, the policy would cover hydrostatic pressure.

overhead photo of a sump pump installed in a collection tank in the basement. How To Relieve Hydrostatic Pressure In The Basement

In Closing

Hydrostatic pressure is a threat to the structural integrity of the basement. The two methods you can use to mitigate the water pressure are shallow depth and deep drainage channel systems. For both ways, you will need a sump pump so that the system will work.

It will cost you around $500-10,000 for the costs of fixing the issue. You might need to repair major walls or floors before installing an interior drainage system. If you have home insurance, the policy might cover the costs of the damages. In the end, you can reduce the hydrostatic pressure when you follow the correct installation process.

Check out other posts about basements:

How Long Does Basement Waterproofing Last?

Can You Fix A Leaky Basement From The Inside?

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