Repairing Sagging Floor Joists & Girders In Your Crawl Space
Permanent Solutions For Reinforcing Joists & Girders, & Preventing Rot Damage
Symptoms of Sagging Floor Joists and Girders in a Crawl Space:
Problems related to inadequate floor joist bracing can show up all over the house, including the following:
- Sinking/Uneven Floors
- Springy Floors Underfoot
- Cracks Forming On Interior Drywall
- Jamming/Sticking Interior Doors
- Moldy Floors
- Sinking Crawl Space Supports
If your home has sagging floor joists and girders, you're dealing with a problem that manifests itself throughout the entire building.
A problem such as this can be caused by many possible factors, but are usually the result of three common issues:
Inadequate Supports: The support system under your home has too few support posts to hold up the structure.
Weakened Floor Joists & Girders: Moisture, rot, termites, wood-boring insects, or other destructive forces have damaged your structural wood.
Support Settlement: Weak supporting soils underneath the crawl space supports have caused the crawl space supports to sink into the ground.
What's Damaging Your Floor Joists & Girders?
If Mother Nature is the cause of your damage, there can be many possible forces hard at work on your crawl space's structural wood. Determining which one you're dealing with can be difficult to do!
Sometimes, a wood surface can be virtually covered in mold, but will still show little evident structural damage. In other cases, the wood may appear to be strong and untouched, while subterranean termites have hollowed the wood out from the inside.
Before you can consider a permanent repair for your crawl space, you will need to address the moisture and humidity that feeds mold, rot, pests, and other unwanted forces in your crawl space. The key to this is to keep your crawl space dry by installing a crawl space vapor barrier system and by running a powerful crawl space dehumidifier system.
The slide show below features six common ways that floor joists and girders in crawl spaces can be damaged.
"Wet" Rot On Floor Joists & Girders
Also called "soft rot", this fungi is known to break wet wood down into cellulose, which will significantly weaken and decompose the material.
When choosing between replacing and reinforcing joists that have been damaged, look carefully at the color of the wood.
Advanced damage will show up as darkening and shrinking of the wood. It will have a soggy, spongy appearance, and will show signs of prolonged moisture exposure.
Often, replacement of this wood will not be necessary. Instead, installing a sister beam and sturdy joist supports may be more than enough to address all present damage, and restore your structure to a stable condition.
Cosmetic, Surface-Level Mold
If you see mold that is white and "fuzzy" growing on your wood, there's a good chance that it's surface-level mold only.
This type of fungi quickly grows all over wood surfaces in a humid environment, alarming homeowners but not usually amounting to significant damage. These fungi are only able to consume the sugars and starches present in the wood, and not the polymers in wood fibers that provide structural strength.
Appropriate protective gear and a EPA-approved cleaning agent can provide a good short-term solution for cosmetically damaging fungi species (some molds are harmful and/or toxic to inhale or touch).
Given warmth, moisture, and food, mold will always return. Addressing the source of moisture is a much better route to the permanent solution you're seeking.
Dry/Brown Rot Damage
Also known as "brown rot", this fungi will reduce the wood it feeds on into small, rectangular pieces, leaving a "red dust" of spores behind as it spreads.
While not quite as widespread as other forms of mold damage, dry rot results in severe structural damage to wood. A 1% decrease of the weight of wood can result in a 75% loss [PDF] in the wood's toughness, causing floor joists and girders to begin to crumble apart in a very short period of time.
Don't be mislead by the name "dry rot" -- it does need significant moisture (a minimum of 28-30% content within the wood).
Dry rot damage can be treated with fungicides (such as boric acid) or other mold treatments to eliminate problems. However, the best way to prevent dry rot and related fungi is to create a dry space.
Wood that's been damaged by termites tends to be hollowed out along the grain, and may look completely undamaged. Inside, you can find ragged-looking "galleries" (tunnels in the wood) that are lied with dried mud, waste, and soil.
Other signs mud-lined "tubes" in visible areas around wood, and the sound made by knocking on termite-damaged wood: which produces a hollow sound. Damage in plaster and drywall may appear as tiny, dirt-lined holes.
Each year, roughly one in 30 homes are infested by termites and this can mean extensive damage to girders and joists.
Similar to termites, carpenter ants damage wood by hollowing it out from the inside. Unlike their counterparts, however, they do not eat wood -- only build their nest inside it. As a result, damage done to wood by carpenter ants is generally far less extensive.
Carpenter ants can be distinguished from termites by their pinched-in abdomen, jointed antennae, and forewings that are longer than their hind wings.
Additionally, carpenter ant tunnels are smooth in appearance, where termite tunnels are rough. Carpenter ants will also leave their nest to forage, and to pile "frass" (sawdust, insect parts, and pupil casings) in locations away from the nest.
Both carpenter ants and termites are moisture-loving creates, and are particularly attracted to moldy, rot-damaged wood.
Powderpost Beetle Damage
The name "powderpost beetle" is a broad term used for several species of wood-destroying beetles that like to infest untreated wood that's been exposed to humid, damp conditions.
Damage caused by these critters is the cause of more confusion than any other structure-infesting pest -- an expert inspection is the best way to identify it.
Powerpost beetle larvae feed on wood cellulose, and will severely damage floor joists, girders, and other structural wood in 1-5 years. Wood they feed upon is reduced to a fine powder, which is deposited in tunnels below the surface of the wood.
Once fully developed, emerging adults will leave tiny, round holes in the wood -- about 1/8" in diameter. They will quickly mate, laying new eggs on or below the wood's surface.
Crawl Space Floor Joist Jacks
Crawl space joist supports are steel, adjustable support posts that are installed to repair sagging floors.
These reinforcing joists install quickly in crawl spaces -- with a complete installation taking about a day -- and provide a permanent solution.
Our SmartJack™ Support System is designed with corrosion-resistant galvanized steel, ensuring that it will be strong and adjustable for decades to come. A unique base of engineered fill prevents sinking support posts when soils below are weak, maximizing effectiveness.
More about our Crawl Space Jacks
Reinforcing Joists & Girders
Compared to other sources of structural damage (frost heave, foundation settlement, bowing foundation walls, etc.) it's relatively easy and inexpensive to reinforce joists and girders in a structurally damaged crawl space.
Girder and joist jacks (also known as "steel lally columns") can be installed at key locations along the structure. Once in place, the floor can be "jacked up" in an attempt to lift the floor back to a level position. If a contractor finds a joist is severely damaged, a sister beam can be installed alongside the normal one for extra strength.
At Dry Pro Foundation and Crawlspace Specialists, we've seen just about everything! Below are just a few of the sagging floor joists the experts in our network have encountered:
(Click to see larger view.)
Light-duty joist braces, such as are found in big box stores throughout North Carolina, should not be as permanet supports.
These joist braces are made out of steel that can rust and corrode, making them difficult or impossible to readjust if the support post sinks down in the soil.
The "Bulb Of Influence"
No matter how strong your floor joist supports are, they can only bear as much weight as the soils underneath them. Put simply, if the supports are sinking, your floor is going to sink with them.
To address this, our contractors take advantage of something called the "bulb of influence".
Before we install your support posts, we excavate a 2' cube hole, filling it in with compressed, crushed stone. Then we place a concrete base on top of the center of this cube, and position the jack post above that.
This cube of compressed, crushed stone disperses the weight pressing down into the soil outwards, dispersing it to approximately 10% of the pressure present at the bearing surface.
This means that even if the soils under the jack posts aren't strong enough to support great weights, your system will still be more than sufficient to support the structure above.
How Do Other Floor Joist Support Methods Measure Up?
There are many different methods of crawl space repair that contractors are using today, and some are much better than others, but all of them work at least some of the time.
Of course, if these repair methods never worked, then they would not be used anymore. However, at Dry Pro Foundation and Crawlspace Specialists, our reputation and written warranty depends on using solutions that will be permanent -- and will work all of the time. They chart below lays out the facts:
We Repair Sagging Floor Joists & Girders In Crawl Spaces!
At Dry Pro Foundation and Crawlspace Specialists, our experts have the experience, training, and warrantied products that you're looking for! With a fast, uninvasive installation, we can provide a lasting solution for your home that will restore your structure and avoid further, potentially expensive, damage.
It costs you nothing to meet with one of our specialists for a professional inspection and written cost quote! To schedule a crawl space repair quote, contact us by phone or e-mail today!
We proudly serve the North Carolina area, including Charlotte, Concord, Gastonia; Rock Hill, SC, Kannapolis, Hickory, Salisbury, Monroe, Statesville, Huntersville Matthews, and many surrounding areas.
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