We have a horizontal crack in a support beam in the basement. Is it serious?

A horizontal crack running along a support beam usually means the beam is carrying more load than it can handle, and that one deserves a look soon. Most fixes land in the $1,300 to $2,500 range for added floor support or the $7,000 to $40,000 range if the beam itself has to be replaced, but we price the real number after we see it. The free inspection tells you which.

Here is the plain version. Beams hold up the floor above. When a beam cracks along its length, the wood or steel is bending and the fibers are pulling apart. That is different from a tight vertical crack in a poured concrete wall, which is often just a shrinkage line. A crack that runs the long way through a beam is a structural signal, not cosmetic. So yes, get it checked.

Serious does not always mean scary. We see beams that have carried a small split for years with no movement. We also see beams that are days from sagging hard. You cannot tell which one you have by staring at it. What we look at: how wide the crack is, whether it runs all the way through, whether the floor above dips or bounces, and whether the posts under the beam are sitting on solid footings or just resting on a slab.

A few things make a beam crack worse over time. Too much weight up top, like a wall added during a remodel without the beam upsized for it. Posts that have sunk because the footing under them was never poured right. Rot at the ends where a beam sits in a damp pocket. And moisture. A wet basement softens wood and rusts steel connectors, so a beam problem and a water problem often show up together.

How we fix a cracked support beam

If the beam is sound but overloaded, the usual fix is more support under it. We add a lally column or floor jack post on a proper footing to share the load. That is the $1,300 to $2,500 item, and it carries a 10-year warranty on floor support and power posts. Quick to install, big difference in how the floor feels.

If the beam itself is split through, rotted, or undersized, we replace it. That is sill and beam replacement, priced in the $7,000 to $40,000 range, and we self-perform that work in-house. No subcontractor handing your basement off to another crew.

If the real trouble is the foundation moving under everything, the beam is just the messenger. Settling on one side, bowing walls, posts dropping. In that case the answer might be helical or push piers to stop the foundation from sinking further, or carbon-fiber straps and bracing on a wall that is leaning in. New Hampshire frost heave does this. Frozen ground swells and pushes, then thaws and settles, year after year, and the loose backfill soil around the foundation drains slow and holds water that makes it worse.

If the crack is a hairline check in the surface of a solid beam and nothing above it is moving, you may not need anything yet. Plenty of beams have small surface checks from drying. We will tell you that to your face and not sell you a post you do not need. What you should not do is ignore a beam that is actively bending or a floor that is starting to slope.

For the cost question itself, see structural and foundation repair. What drives the number is which fix the beam needs: a single support post is the low end, a full beam swap is higher, and pier work to stop foundation movement is its own job. We give you the figure in writing after the free inspection, and financing is available through Hearth, subject to approval. We make nothing on the financing.

On the moisture side, if your basement is damp, fixing the beam without fixing the water just starts the clock again. Interior drainage and a dry basement keep wood and steel from going bad in the first place. That is the Forever Dry System, 100% guaranteed to be dry for life. Read the 603 guarantee for how our warranties transfer.

For independent background on home structural risk and what insurance does and does not cover for foundation issues, the Insurance Information Institute (iii.org) is a good neutral read.

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If you have a horizontal crack in a beam, do not wait it out. Call us at 603-610-1770 or book your free inspection and we will tell you exactly what your beam needs and what it costs. Free inspection, free estimate, quote within 24 hours!

Related questions

Is a horizontal crack worse than a vertical one? In a foundation wall, yes, horizontal cracks usually mean pressure pushing the wall in, which is more serious than a vertical shrinkage crack. In a beam, a crack running the long way through it is the one to act on. Either way, get it looked at.

Can you just add a post instead of replacing the whole beam? Often, yes. If the beam is sound but overloaded, a lally column or jack post on a real footing takes the load. That is the $1,300 to $2,500 route. We only replace the beam when it is split through, rotted, or undersized.

Will my homeowners insurance cover a cracked support beam? Usually not for normal settling or wear, since most policies exclude earth movement and gradual deterioration. It depends on your policy and the cause. The Insurance Information Institute (iii.org) explains the common exclusions. Check your specific policy.

Does a wet basement cause beam problems? It can. Moisture rots wood beams and rusts steel posts and connectors over time, so water trouble and beam trouble often show up together. Drying the basement with interior drainage protects the structure you just paid to fix.