Do the floors above your crawlspace seem bouncy, soft or unlevel? If so, then you know that sagging floors are not only a nuisance, but can be dangerous. They can leave you wondering how much longer can my floor support everything on it. Here are some signs to look for.
Signs of Sagging Floors
- Floors slope, sometimes creating a gap between the floor and interior walls
- Cracks and gaps around door frames occur
- Doors stick or have been planed down in order to close properly
- Gaps appear between existing columns and girders in your crawlspace
Causes of Sagging Floors
When your home was built, chances are good that the floors were strong enough and level. So, what created the problem? There are three main causes of sagging floors. it's important to understand them, because only a solution that addresses these root causes can permanently fix the problem
Existing columns are spaced too far apart
When a crawl space is built, either with block, brick, or wood columns are located throughout the crawl spcae to support the weight of the structure above. If those columns are spaced too far apart, the beam can become overloaded and sag between columns. The girder sags with it and so does the floor above.
Floor joists and girders have weakened
Because crawl spaces are often unsealed from the earth, excess moisture and humidity is a problem, And what happens to wood when it has been expose to moisture and humidity? It begins to rot, get moldy and become weak. When weakened girders and floor joists are unable to continue supporting the weight above, and the floor about the crawl space becomes bouncy, soft and may begin to sag.
Existing columns have settled
In previous blogs we've discussed the problems soil can cause, and it's not different here. Weak soil can cause the existing columns in the crawl space to sink or settle, often creating a gap between the top of the column and the bottom of girder it was supporting. Once the column settles, the girder sags and the floors above sag. It's a chain reaction.
Solutions for Sagging Floors
Stabilizing your home's foundation is serious business. To start off, you will need to find a trustworthy, specialized contractor. That's where we come in. With all of our solutions we will solve your problem permanently. There are many solutions to choose from and of course, some more effective that others. In situations like theses, what you don't know can hurt you.
The following section is an overview of the options available to you based on the science behind foundation repair, That way, you can make an informed decision. Let's walk through an evaluation of the most common repair methods that we offer.
Options to avoid
The Process. Concrete footings are poured throughout your home's crawl space. After the concrete footings cure, concrete blocks are stacked on top of the footings. After the mortar cures, shims are placed between the uppermost concrete block and the girder. This may appear to be a good solution because concrete is a strong material, or because it is most commonly used my contractors.
The Problems. Not only is this solution time consuming, but it is also not adjustable. As the concrete columns later settle into the soil below, additional shims may need to be added. In other words this is a fix that will need to be repeated again and again.
The Process. A temporary jack is used to lift the girder and make room for the shims. Shims are then pushed between the existing column and the girder. The temporary jacks are removed. This option may seem attractive because it is relatively easy and inexpensive.
The Problems. This one come down to the old adage: you get what you pay for. Additional shimming is only a temporary fix. You will find yourself repairing damage to upstairs finishes over and over again. This in another option that doesn't address what's causing your problems.
Light Duty Jack Post
The Process. A concrete block is laid on top of the soil and a light-duty jack post is set into place. The light-duty jack is then tightened to fit against the girder. Some may suggest that this problem can be handled with a do-it-yourself project. These light-duty jack post can be purchased at your local hardware store and you may be temped to give it a shot... forgetting that some projects should be left to the experts.
The Problems. Light duty posts were never intended to support the weight of live loads and load bearing walls. They have adjustable top brackets designed only to tighten them up against the beam above. not to lift the floor. They are made of thin, unprotected or spray-painted steel that rust, corrodes and weakens over time. Most importantly, these post do nothing to address weak soils that can give way under their base, even when they are set on a concrete block or pad.
Options That Work
The SmartJack System
SmartJacks are steel support systems used to permanently stabilize and level the girders and floor joist in a crawl space. The steel components have been laboratory-tested and verified to support loads many times greater that what is actually required to stabilize a sagging floor and any partition walls resting on that floor. SmartJacks do not replace the existing columns and piers, but add strength and stability to what is there.
The Process. To address weak foundation soils, or the effects changing moisture conditions can have on these soils, a two-foot cube of soil is excavated at each SmartJack location. The hole is then filled with concrete or engineered fill to creat a stable, load-bearing footing. The custom-engineer SmartBase is then positioned on top of this base to hold the SmartJack in place and properly distribute loads. Next, high strength, galvanized steel tubing is cut to the appropriate height. The steel column and components are assembled and connected to the support beam and the SmartJack system is tightened into place. The support beam and floor joist are immediately stabilized and the above floors and walls can be lifted back towards level.
When to use them. SmartJacks should be used when your looking for these outcomes:
- Lift the above floors and walls back towards their original position
- Reduce floor 'bounce' caused by excessive floor joist spans
- Solve the problem once and for all
The Bulb Of Influence
This is what really sets the SmartJack system apart from other repair options. It works differently, based on sound engineering. For those who are asking, "Why do you excavate only a two-foot cube at each SmartJack location? Wouldn't it be better to go deeper," ...keep reading.
Here's how the engineering works: at a depth of twice the bearing width, bearing stress dissipate at approximately ten percent of those at the bearing surface. What does that mean?! In other words, the SmartJack pre-cast concrete base and cast aluminum base are 12 inches wide. This is the bearing width. Two times 12 inches is 24 inches, or two feet.
So, at the bottom of the two-foot hole, the pressure that was being exerted at the structural footing bas is reduced down to only ten percent of what it was. Even if the soil at the bottom of the excavated hole isn't all that strong, you can be assured that the 'Bulb of Significant Stress Influence' has already been distributed within the compacted crushed stone or recycled concrete fill.
The bottom line: the SmartJack system is smart. It reduces stress on the original soil by 90-percent. Any system that does not address these concerns will not be a long term solution.
Advantages of the SmartJack System
- It's the only solution for the core issue: problem soils under your home.
- Engineered fill replaces the troubled soils, supports and dissipates the column load, and is unaffected by changes in moisture.
- Heavy-duty, threaded rods are designed to lift the floor back to its original positions.
- Once installed, it provides immediate stabilization and lift.
- It's engineered to support large loads, and suitable for large homes and load-bearing wall construction.
- Installation is quick (often in less than one day) and can be done year-round.
- Made of zinc-plated and hot-dip galvanized steel to prevent rust and eliminate weakening from moisture, mold and wood rot.
- Can be installed in conjunction with a crawl space liner, which protects your crawl space from the elements.