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Crawl Space Beam, Girder, and Joist Problems

Crawl Space Beam, Girder, and Joist Problems: How to Repair

Problems start appearing in old houses with time. These problems are linked to crawl spaces. This includes an un-level floor or sagging. 

Why do these problems start appearing in the house? Well, it depends on your location, including some other factors. For example, US states’ crawl spaces are vulnerable to wood rot. 

The crawl spaces also get affected by insects or water damage. Though, this problem is not because of wood rot. It is the soil settlement issue. Multiple things can cause problems. But what’s important is that the problem is solved timely. Otherwise, the home structure will worsen. 


The difference between Joists – Beam vs. Girder

People usually confuse the difference between a beam and a girder. We have stated the difference below: 

Grinders or Beams

The girders or beams in the crawlspace, typically between 4″ and 6″ by 8″ in size, support the floor joists. These floor joists are parallel to them. Commonly, this is referred to as a girder in California. However, they are known as beams in the Western and Eastern states. Therefore, the meaning of these terms, beams vs. girder, will vary depending on the location. 


Crawl space joists are horizontal structural members that support the floor of a building above a crawl space. They are typically made of wood and are installed parallel to each other, spanning the distance between the foundation walls or piers. Joists provide crucial support and distribute the weight of the floor and any loads applied to it, transferring them to the foundation or supporting beams.

In a crawl space, joists are essential for maintaining the structural integrity of the floor system. They are usually spaced apart at regular intervals and can be of varying sizes and dimensions, depending on the specific building requirements and the weight they need to bear.


Crawl Space Beam, Girder, and Joist

Crawl space joists are susceptible to damage and deterioration due to various factors, such as moisture, pests, and age. Sagging or damaged joists can lead to an uneven or weakened floor, compromising the stability of the structure. It is important to regularly inspect and maintain the crawl space joists to ensure their structural integrity and address any issues promptly to prevent further damage.


Crawlspace Beam, Girder and Joist


Common Problems of a Sagging Crawl Space

A sagging crawl space can present various problems that should not be overlooked. One of the most common issues is the increased risk of structural damage to the foundation and floors above. As the crawl space sags, it puts additional pressure on the supporting beams and joists, potentially leading to their weakening or even failure. This can result in uneven floors, noticeable cracks in walls, and doors or windows that no longer close correctly. Moreover, a sagging crawl space can create an ideal environment for moisture accumulation and subsequent mold and mildew growth.

The excess moisture can permeate the wooden components of the crawl space, leading to rot, decay, and insect infestations. Furthermore, the compromised integrity of the crawl space can allow for the intrusion of pests such as rodents and termites, which can cause further damage to the property. Therefore, addressing the issues of a sagging crawl space promptly is crucial to prevent these common problems from escalating and affecting the overall safety and value of the structure.

Causes of Beams and Joist Problems in Crawl Space

Crawl spaces start worsening over time. There are many reasons of a sagging floor. This includes too much water and inadequate support. The lack of floor joints is also one of the reasons behind crawl spaces. 

Lack of Floor Joists

Instead of employing floor joists, some floors are built using plywood subfloors. These floors are supported by 4″x6″ beams spaced four feet apart. This flooring can become spongy and dip near walls because they lack support from below. To solve this issue, more help can be added between the existing floor girders by inserting floor joists or beams.

Water Intrusion

Too much water can lead to various foundation issues, including issues with crawl spaces. A crawl space with standing water warns that surplus water is entering the area from anywhere. 

If you notice this, you should contact a drainage specialist to remedy the issue. You can change the support posts using shims or switching out the support posts with screw jacks.


Water Intrusion


Soil Problem

Beams and girders support the crawl space that is above the floor. But the support girders and beam weaken when the soil is imperfect. The ground should be strong enough to support the house structure. Otherwise, you will need to consult a professional to inspect your house. 

Less Support

If the construction of the floor system were faulty in the first place, crawl spaces would start to sag. This means that such a problem existed from the start. But it wasn’t evident as the house was new. 

If that’s the case, adding support girders can be a solution. Place them between the existing beams and add some concrete footings. You can use screw jacks to eliminate the span among the existing rafters. 


How To Repair A Sagging Crawl Space?

Repairing a sagging crawl space requires careful planning and execution. Here are some steps to consider:

Begin by thoroughly inspecting the crawl space to determine the extent of the sagging and identify any underlying issues. Look for signs of moisture, mold, insect, and structural damage.

Moisture is often a contributing factor to crawl space sagging. Install proper drainage systems, such as French drains or sump pumps, to redirect water from the area. Ensure that the crawl space is properly sealed, and consider installing a vapor barrier to prevent moisture intrusion.

Sagging crawl spaces are typically caused by weakened or damaged support beams and joists. Reinforce these structural elements by sistering additional beams or adding support columns. If the damage is extensive, it may be necessary to replace the damaged components entirely.

Use jacks or hydraulic lifts to gradually raise and level the sagging areas of the crawl space. Take care to distribute the load evenly to avoid further damage. Once leveled, secure the beams and joists in their corrected positions.

Proper ventilation and insulation in the crawl space are essential for maintaining a stable environment. Ensure adequate airflow and insulation to prevent moisture buildup and temperature fluctuations.

Regularly inspect the crawl space for any signs of recurring issues. Keep an eye out for moisture, pest infestations, and structural changes. Address any problems promptly to prevent further damage.

It is important to note that repairing a sagging crawl space can be a complex task, and it is advisable to seek professional assistance, mainly if the damage is extensive or if you lack experience in structural repairs. A qualified contractor or foundation repair specialist can provide expert guidance and ensure the repair process is carried out effectively and safely.


What is the Overall Cost to Repair it?

The price of fixing issues with beams, rafters, and joists in a crawl space depends on various factors. Everything depends on the kind of damage and the necessary repairs. Therefore, providing you with even a rough estimate would be inaccurate. 

The simplest method to find out how much it will cost to fix a crawl space issue is to call a foundation repair expert. They will conduct an inspection (most offer these services without charge) and estimate.

Crawl space foundations are included in many residences. Crawl spaces are beneficial because they make it simple to access a house’s wiring and plumbing, among other things. 


Crawl Space Beam, Girder, and Joist FAQs

How does the girder beam work?

A construction support beam is called I-beam. It serves as a structure’s immediate horizontal support and grasps smaller beams. Girders often have an I-beam cross-section made up of two load-bearing extensions spaced. A stabilizing web separates them, although they can also be a box, a z, or another shape.

How do you brace a crawl space?

There are 6 Ways to Protect the Crawl Space of Your New Home

  1. Seal all the openings. 
  2. Install interior drain
  3. Crawl Space Encapsulation.
  4. Insulate the Crawl Space. 
  5. Get a Dehumidifier. 
  6. Look at Your Landscaping.

How do you repair a floor joist?

Floor joists are repaired by sistering a fresh piece of wood to the damaged post. The new part of timber often extends the whole length of the previous one. Shorter portions are employed in cases where this isn’t possible (sometimes called scabbing).

Are crawl space jacks permanent?

Yes, crawl space jacks are permanent, which provide a fast and guaranteed solution to the problem of home repairs. They are the best option for those homeowners who want to invest in long-term repairs. 



The floor of old houses starts sagging over time. This happens when beams, girders, and joists begin to fail in the crawl space. Such a problem should not be ignored. If you notice crawl spaces, it is better to consult a professional to inspect your home’s condition. 


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