Cracks in Basement Wall: When to Worry and When to Relax
Most cracks in a basement wall are not an emergency. A few are. The trick is knowing which kind you're looking at.
If you've found cracks in your basement wall and you're wondering when to worry, start here. We're Dependable Concrete LLC, a family-owned crew that's been working in Philadelphia basements since 1984. We look at a lot of cracked walls. Here's how we sort them out.
Short answer: Thin, dry hairline cracks that aren't changing are usually just the wall settling in and drying out. Cracks that are wider than about a quarter inch, getting longer, letting water in, or where one side sits higher or further out than the other are the ones to get looked at soon.
Why Basement Walls Crack in the First Place
Concrete shrinks a little as it cures. That alone puts thin cracks in plenty of poured walls, sometimes within the first year. Older Philly basements have their own reasons. Stone and brick walls with old cement coats crack along the joints as the coat ages and the ground pushes and pulls through the seasons.
Water plays a part too. Wet soil gets heavy. It freezes, it thaws, it swells and shrinks. Your basement wall sits in the middle of all that, year after year.
So a crack doesn't automatically mean something is wrong with the house. It means the wall is doing what walls do. What matters is the size, the shape, and whether it's changing.
Cracks That Are Usually Normal
These are the ones we see all the time and usually don't lose sleep over:
- Hairline cracks. Thin enough that a business card barely slides in. Often running straight up and down.
- Dry cracks. No water marks, no white powder, no damp edges after a storm.
- Cracks in the coating only. The cement coat on an old stone wall can crack and flake while the wall behind it is fine.
- Cracks that look the same as last year. If you've been walking past it for a while and nothing's changed, that's a good sign.
Normal doesn't mean ignore it forever. A hairline crack can still let moisture through over time, and a small crack is an easy fix. It just isn't a reason to panic.
Cracks That Mean Trouble
Here's when to worry. Call someone if you see any of these:
- Wider than a quarter inch. Bigger gaps let more water in and can mean more is going on.
- One side higher or sticking out further than the other. If you run your hand across and feel a step, get it checked.
- Getting bigger. Mark the ends with a pencil and write the date. If it grows past your marks, that's your answer.
- Water coming through. Wet edges, drips, or a puddle under the crack after rain.
- Stair-step cracks along the joints of a block or brick wall, especially if they're opening up.
- Long sideways cracks running across the wall.
- Doors and windows upstairs sticking at the same time new cracks show up.
None of these mean the house is coming down. They mean it's time for a person to stand in your basement and look at it.
How to Check Your Own Cracks
You don't need special tools. Grab a flashlight, a pencil and your phone.
- Take a photo of each crack with something next to it for size, a coin or a tape measure.
- Mark both ends with a pencil line and the date.
- Check after the next big rain and again in a month.
- Feel along the crack. Is it flat, or does one side stick out?
If nothing changes and it stays dry, you've got time. If it grows, gets wet, or you feel a step, call.
Basement Wall Repairs: What the Fix Looks Like
Basement wall repairs depend on what kind of crack you have and what the wall is made of. Most jobs we do go something like this:
- Look first. We check every wall, not just the crack you called about, and figure out where any water is coming from.
- Open and clean the crack. Loose material has to come out so the repair has something solid to grab.
- Fill it. We pack the crack with cement so it's solid all the way through.
- Coat the wall if it needs it. On old stone and brick walls, a full new cement coat ties the whole thing together and gives you a smooth, even surface.
- Clean up. We leave the basement swept.
We mix our own concrete. We run our own silo and mixers, so we control the strength of every batch and can add fiber when the job calls for it.
If a crack turns out to be something outside what we do, we'll tell you that straight and tell you who to call.
Video transcript
Welcome to another dependable concrete video. Today we're taking you to the Frankford section of Philadelphia where we transform the basement with peeling and dusty walls into a space with flat new walls. You won't believe the difference. When this job is complete our client will have a basement where she can do laundry in a bright and dust-free environment. Before we begin applying cement to the walls we wrap pipes, meters, windows and other critical components to protect them from splatter. To access the entire wall we simply remove the washer, dryer and stationary tub. Our aim is to ensure no area is left undone and to thoroughly cement all surfaces. To ensure a long-lasting durable result we've prepped the walls by scraping off any loose materials which would prevent the cement from sticking to the wall. Furthermore we've covered and protected the concrete floor from cement splatter. Because we are cementing a painted wall we have to apply a special cement for the first coat, the scratch coat. Regular cement will not stick to paint. The scratch coat has been applied and now we are ready to apply the second and final coat. It's time to mix the cement. For a reliable job we use three buckets of sand to one 70 pound bag of mortar cement to a quarter pound of fiber. Fiber strengthens the cement to prevent cracking. We are now spraying the last and final coat to the wall. There are several methods to apply cement to the wall. We choose spraying the cement because it's much quicker and efficient. In addition it's easier for us to apply cement to tighter areas such as between floor joists. Mice infestations in homes are a result of mice traveling between the floor joists back and forth from neighbor to neighbor. Currently our staff is actively smoothing the cement immediately after it's sprayed. This is a crucial phase as they focus on leveling and flattening the cement. Our objective is to deliver aesthetically pleasing basement walls that are as flat as drywall. Observe the flatness and smooth texture of these walls. They match the flat walls found upstairs creating a consistent aesthetic flat look throughout the house. In summary we have applied a sticky scratch coat followed by a final coat. Additionally we have sprayed cement between floor joists to prevent mice infestation. And finally we are going to brighten this dark basement by spraying the walls white. Using a paint sprayer can save time and money by covering large areas quickly and evenly providing precise and even coverage with a consistent finish. Notice how the basement is becoming brighter. White paint is the best choice for reflecting light and brightening up a dark space. Again our goal is to eliminate a drab basement and convert it to a bright dust-free space. This job is now complete and our client is very satisfied with the remarkable transformation of her basement. Our team at Dependable Concrete has ensured a high level of craftsmanship and attention to detail resulting in walls with sharp corners and a bright and dry basement that is now free of dust, rodents and creepy insects. With our work completed our client can now pleasantly carry out her laundry routine, safely store delicate personal items and simply enjoy a much-improved experience in the largest room of her house. Please like share and subscribe to stay informed of our next video release. Thank you.
When Should You Call?
Call sooner if water is coming in, if a crack is growing, or if one side is out of line. Those don't get better by waiting, and winter freeze and thaw tends to make them worse. If water is coming through, our basement waterproofing in Philadelphia page explains how we fix the wall and keep it dry.
Call when it's convenient if you've got hairline cracks you'd like sealed up, or an old wall that's starting to flake and crack all over. It's inside work, so we can do it any time of year.
We won't guess over the phone. We come out, look at the walls, and put it in writing. Your written estimate within 24 hours of our visit.
Working Across Philadelphia
Our shop is at 7715 Crittenden St in Chestnut Hill. We work in basements in Mt. Airy, Germantown, Roxborough, Manayunk, East Falls, Northeast Philly, West Philadelphia, Center City, South Philly and Fairmount, plus Cheltenham, Glenside, Wyncote, Abington and Jenkintown. A lot of these homes share the same kind of foundation, so the cracks tend to look familiar.
FAQ
Are vertical cracks in a basement wall normal?
Thin, dry vertical cracks are common, especially in poured walls. Keep an eye on them. If they widen, leak or one side shifts, get them looked at.
How wide is too wide?
As a rule of thumb, anything wider than about a quarter inch, or any crack where one side is higher than the other, is worth a visit.
Can I just fill it myself?
You can patch a small dry crack. If it's leaking, growing or out of line, a patch will just hide the problem for a while.
Can you fix cracks in winter?
Yes. The work is inside, so the cold outside doesn't stop us.
Get Your Cracks Looked At
Dependable Concrete LLC is family-owned and has been doing concrete and basement work in Philadelphia since 1984. We're open 7 days a week, 7 AM to 7 PM, and we call back.
Dependable Concrete LLC
7715 Crittenden St, Philadelphia PA 19118
215-821-9779
https://dependableconcrete.com
Your written estimate within 24 hours of our visit.
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