Sagging Crawl Space Problems

Sagging floors above your crawl space are more than just annoying. They're a danger to your home's structural health and your family's safety. Learn more about the causes and repair solutions for sinking, sagging crawl spaces.

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The Problems That Are Happening:

sagging floors in crawl space graphic

If your crawl space is experiencing structural problems that are causing it to sink or sag in the middle, it generally is due to one or more of these three primary reasons:

  • Support Columns Spaced Too Far Apart

When a crawl space is built, columns made of block, brick, and even wood are located throughout the crawl space. These columns are designed to support the weight of the home above.

If these columns are spaced too far apart from each other, the beams and girders may be overloaded with weight, causing them to sag between the columns. When the girder sags, so does the floor above it.

  • Rot-Weakened Floor Joists/Girders

Because crawl spaces are often not sealed from the earth around them, excess moisture and humidity is a common problem. This moisture creates an environment where mold and rot can thrive, damaging the wood structure of your home.

The weakened girders and floor joists will be unable to continue to support the weight above. In time, the floor above the crawl space will become bouncy, soft, and will. In some extreme cases, the floor may even collapse.

  • Columns Settling Due To Weak Soil

Often, the soils that the crawl space supports are installed on are not strong or solid enough to support the weight being transferred from the home. Weak supporting soils will allow your existing crawl space columns to sink or settle, often creating a gap between the top of the column and the bottom of the girder it supports.

Once the column has settled, the girder above will begin to sag as well.

Telltale Signs:

  • Tilting or sinking crawl space supports
  • Moist, rotting wood
  • Sagging, sloping, or uneven floors upstairs
  • Cracks in interior drywall
  • Door & window frames skewed and/or unlevel

How to Fix It:

Additional crawl space supports should be installed to ensure that your structure is properly stabilized. Mold and rot should also be addressed by installing a crawl space liner and removing excess moisture from the crawl space. How do you do this? By contacting the expert team at Innovative Basement Authority that can fix your sagging crawl space!

Advantages To Our System:

At Innovative Basement Authority, we recommend installing the IntelliJack™ System, which uses adjustable heavy-duty steel crawl space jack posts. These posts install quickly in a home and provide the best solution for restoring stability to your structure.

The IntelliJack™ system can be installed in tight conditions, usually in less than a day. Our crawl space support system has an allowable load capacity of more than 24,000 pounds per support jack and is tested and certified to the highest industry standards.

The adjustable design of our crawl space jack system means that sagging floors can not only be stabilized; they can also be restored to their original position in many cases.

To address the issue of poor supporting soils, each crawl space jack distributes the weight of the home through a precast concrete footing and a base of engineered fill material.

The IntelliJack™ is the only solution that addresses problem soils during crawl space restabilization!

Installing the IntelliJack™

Installing the IntelliJack™ system is a fast process that will not disrupt your home or landscaping. During our crawl space repair, your installers will follow these five steps:

Preparing For Installation

Before the installation, a Certified Field Inspector will meet with you to design a crawl space support system that will effectively return your home to structural stability. Our specialist will also be able to explain our system and answer any questions you may have about your crawl space repair.

The location for each crawl space support jack will be mapped out for your installers when they arrive, ensuring a proper installation.

At the beginning of the installation, our team of in-house crawl space repair contractors will excavate a 2′ square, 2′ deep hole at each IntelliJack™ location. Each of these holes will be prepared with engineered fill consisting of tightly compacted crushed stone.


Placing the Pre-Cast Footing

A pre-cast concrete base (or footing) is placed on top of the engineered fill and carefully leveled.

The footing serves as a stable base for the steel jack post, keeping it vertical and distributing the weight bearing on the post across a broad area of soil. The engineered fill base underneath the footing provides solid support that won’t shift, settle, or be affected by soil moisture. Some building codes may require a poured concrete base rather than engineered fill.

By the time the weight is distributed through the pre-cast base and the fill, the bearing stresses have dissipated to approximately 10% of the stresses at the top of the post. This means that even if you have weak supporting soils, you can be assured that the weight of the building will not exceed its bearing capacity.


Cutting the Jack Posts to Length

Once new bases have been installed, measurements are made for the steel crawl space jack posts, and the posts are cut to length.

The steel tube used in each IntelliJack™ is manufactured with a triple-layer, in-line galvanized coating. The triple-layer coating process includes :

  1. A uniform hot-dip zinc galvanizing layer
  2. An intermediate conversion coating enhances corrosion resistance
  3. A clear, organic top coating to further enhance appearance and durability.

Additionally, the inside of the pier tube also has a zinc-rich coating.

The remaining steel components of the IntelliJack™ come standard as zinc-plated in accordance with ASTM B633, “Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel”.

Once the IntelliJack™ has been installed in your home, you can rest assured that you’ve invested in a high-quality, permanent solution for your crawl space issue.


Assembling & Tightening

Each crawl space jack post is assembled in your crawl space. The top of the crawl space jack is mounted against the girder, and the installation is carefully plumbed.

In cases where existing girders are undersized or damaged by rot, a new sister girder may be installed alongside the original in order to strengthen and reinforce the structure.

Each IntelliJack™ is then tightened in an attempt to lift the floor back to its original position. In many cases, your contractors will be able to straighten and level floors, close cracks in walls, and halt future downward movement. The jacks will continue to be adjustable for future tightening, should you need it.


Encapsulating The Crawl Space

If your wood crawl space joists, girders, and/or supports were damaged by mold, rot, and moisture, then you will want to address these issues to prevent future damage.

The encapsulation process involves sealing all crawl space vents, installing an airtight crawl space door, and lining crawl space walls and floors with a durable plastic liner. This treatment can also include additional drainage measures like installing interior drains and a sump pump.

Encapsulation stops moisture-related damage and associated structural problems that occur when framing members rot and deteriorate. By investing in crawl space encapsulation, you’ll also improve overall home energy efficiency and indoor air quality.

What NOT To Do

Here are three “fixes” that we at Innovative Basement Authority do NOT recommend:

crawl space repairs done with concrete cinder blocks and wood shims in a Bemidji home

Concrete Columns

Crawl space girders or beams are sometimes supported by columns made from concrete blocks. The blocks are typically stacked on a concrete footing and held together with mortar.

Once the column has been built and the mortar has cured, the extra space between the uppermost block and the floor girder above is filled with wooden spacers or “shims“.

Because of the wait for the concrete footing and mortar to cure, this is a very slow, time-consuming process.

Since the completed column isn’t adjustable, additional shimming will be needed as the concrete column settles or the wood girder shrinks.

a poorly designed crawl space support system installed in a Maple Grove home

Additional Shimming

This is a “cheap fix” solution for repairing a girder and floor that have sagged because of settled concrete columns. Temporary jacks are used to lift the girder, and wooden shims are pushed between the existing column and the floor girder. The jacks are then removed.

This is a short-term fix only – the concrete columns will continue to settle, requiring additional shimming and maintenance in the future.

Light-Duty Jack Posts

Skinny, light-duty jack posts are available at many hardware stores and home centers. This type of adjustable steel post is often installed on top of a concrete block that rests on the ground in the crawl space.

Unfortunately, these posts hold very little weight, have poor stability, and are difficult to adjust. Also, they won’t compensate for poor supporting soils in the crawl space. This is not the solution you need!

We’re YOUR Crawl Space Structural Support Contractors!

If you’d like a permanent solution for your crawl space issues or any other foundation problem, we’re ready to help you. We offer free crawl space structural repair quotes to homeowners in the Minnesota, North Dakota, and Eastern Montana area. To schedule your free, on-site visit and written estimate, call or e-mail us today!

Our service area includes Minneapolis, St. Paul, Fargo, Bismarck, and nearby areas such as Saint Cloud, Bismarck, Grand Forks, Eden Prairie, Anoka, Andover, Minot.

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