I had my concrete pad raised but it settled again, why did it do this?
Whether a pad sinks after it’s been raised depends on:
- The age of the Pad. A pad sinks in the first place because the soil under the pad was never compacted properly. It takes time for uncompacted soil to compact so obviously there’s more chance of a newer pad sinking again after it’s been raised, compared to an older pad. Even replacing a new pad doesn’t guarantee it won’t settle again. Future settlement depends only on how well the soil under the pad is compacted.
The problem with raising any pad is, no one except the contractor who built the building truly knows how much uncompacted fill was placed under a pad. If it was minimal, the pad probably won’t sink again. If the uncompacted fill was fairly deep, it may not be fully compacted yet and future settlement is possible.
- How much water gets under the concrete pad. Even poorly compacted soil won’t settle as much if it remains dry. Allowing water to get under a concrete pad can compress the soil even more, resulting in the concrete pad settling in the future. Water makes hard compacted soil soft, also resulting in the concrete pad settling. Nearby downspouts, improper slope of a pad, cracks in a pad and poor landscaping are the most common reasons why excess water drains under a concrete pad.
- Whether the concrete pad is filled properly while it’s being raised. A concrete pad is less likely to sink again if the entire area under a pad is filled as best possible. This helps prevent water from easily traveling underneath, and helps distribute the load of the concrete pad evenly on the ground.
What’s the best way to raise concrete: Mudjacking or Polyurethane Foam?
Mudjacking definitely has its advantages for raising concrete, compared to foam.
- Mudjacking material is non-expanding, making it easier to control the concrete pad when raising and filling voids.
- Mudjacking material doesn’t set up hard right after it’s installed and will stay soft for a few hours. This allows the concrete pad to float up to its original height rather than being forced up, which occurs when raising a pad with foam. Floating the concrete up provides less stress on the concrete. This gives a higher success rate while raising the pad to its original height. A common problem while raising a large majority of sunken pads is that they need room to move lengthwise and/or sideways to achieve their proper elevation. Sitting a concrete pad on a soft layer of mudjacking material allows for the pad to slide one way or the other while it’s being raised. This makes it easier to ensure the pad comes back to its original height and shape without creating numerous cracks in the pad. This is a common problem when raising a pad, and is one of the main benefits to mudjacking.
- Because polyurethane foam material sets quickly, makes it more difficult than mudjacking to adjust the concrete pad, match trip spots and properly fill the pad in the process.
- Polyurethane foam has its limitation on which jobs can be raised.
- With mudjacking, having the pad sit on a soft layer of material and floating the pad to elevation, allows a mudjacker to raise both easy and difficult jobs.
My pad is sinking but I’m not sure the settlement is done. Should I raise the pad now or let it settle more?
It’s always better to raise a pad before it sinks too much. The reason a pad sinks is because the soil under the pad was never compacted properly in the first place. When a pad settles, parts of the pad are on the ground, while other parts are left with voids underneath. This causes undue stress on a pad, resulting in it cracking more than it should. The voids also make it easier for water to gain access underneath, which can cause it to heave in the winter, creating more cracks. The other problem is, once water is under the pad it is hard to tell where it travels. In many cases water under the pad can find its way back to the house foundation, contributing to structural problems or a leaky basement.
Which fills a pad better, Polyurethane Foam or Mudjacking?
Although foam is engineered, the biggest problem is the installation isn’t engineered. Because polyurethane foam is an expanding material, makes it difficult to fill voids. There are risks of raising the concrete pad too high when trying to fill the voids with an expanding material. How much foam to add under a pad when filling voids is a guessing game. There is specialty equipment to help measure the movement in a concrete pad while filling voids, but that doesn’t help determine if the concrete pad is properly filled.
Caliber Mudjacking tries to minimize this problem by drilling the holes 3 to 4 feet apart in all directions when raising a pad with foam just as we do when mudjacking a pad. Although this procedure takes longer to accomplish and uses much more foam, drilling the holes closer together will minimize the amount of voids under a pad when using foam.
With Mudjacking, it’s much easier to fill the voids properly.
Mudjacking material is more controllable because it’s non-expanding and travels well under a pad. It is a flowable material. You can tell if the pad is full underneath because of back pressure that occurs when removing the hose from the injection hole. It’s much easier with mudjacking to know when the voids underneath the pad are filled without raising it too high or putting unnecessary cracks in the concrete.
Which is cheaper when raising concrete, Mudjacking or Polyurethane Foam?
The main difference between mudjacking and polyurethane foam is cost of material. Polyurethane foam material costs approximately 250% more than mudjacking material.
If you compare apples to apples, Mudjacking will always be cheaper.
For example, when I raise the top of a driveway and front sidewalk, it takes approximately 4 to 6 yards of material to mudjack the pads back to their proper height. It will cost approximately between $1,800.00 to $2,200.00 dollars for material and labor to mudjack the top of driveway and front sidewalk.
A Barrel set (9 yards of material per barrel set) of foam costs approximately $3,600 Canadian funds to import from the United States (includes exchange rate, shipping and brokerage fees). If you take an average and used 5 yards of foam to properly raise and re-support the top of the driveway and front sidewalk, it would cost $2,000.00 for 5 yards of foam and approximately $200.00 for the injection ports that are used to inject foam under this pad. Material alone for foaming this job would cost $2,200.00 and you still have the labor cost to raise the driveway and sidewalk. The cost of material alone for foaming this job is the same cost or more than what I would charge for the material and labor to mudjack this job.
This results in polyurethane foam costing 50 to 80 percent more to raise the concrete when done properly as the same mudjacking job.
Having voids under concrete around the Peace Region is common and the depth of the void can be quiet substantial. The only way raising a pad with foam can be cheaper is if the holes are spread father apart than they should be, skipping holes that are needed to fill a pad properly and supporting it on foam piles. This leaves a lot of voids under a pad, which doesn’t support the pad properly, and allows water to travel underneath. It’s not only that some foaming companies do this but some mudjacking companies do this also. You can tell how well a concrete lifting company fills a pad by the distance the holes are drilled apart, and the number of rows they install in the pad. When it comes to raising concrete, experience and honesty do matter!
How far are holes placed apart when raising concrete?
Regardless whether the pad is going to be raised by Mudjacking or Polyurethane Foam, the hole pattern is basically the same. Depending on the type of job and how sunk the concrete is, typically the holes are placed 3-4 feet apart.
The number of rows of holes depends on how much the concrete is sunk and the distance it is sunk. The majority of pads take a minimum of 2 rows of holes while larger pads take more. Even a 5-foot wide sidewalk usually requires 2 rows of holes to fill it properly.
My driveway is sunk by the garage but is moving up during the winter. If I raise the pad back to its proper height, I feel the pad will raise higher next winter. Should I raise the pad or just leave it as is?
The reason pads move up and down is because water is gaining access underneath the concrete. Usually the problem is caused by a nearby downspout. Improper landscaping around the concrete pad adds to the water problem. Positive drainage needs to be maintained to direct water away from the concrete. A drainage problem is more noticeable in the winter months when snow blocks the flow of water, resulting in it draining under the pad. Frozen water underneath the pad causes the concrete to heave in the winter months. This problem can be solved by properly maintaining downspouts so water drains farther away from the foundation and the concrete pad. Having cracks and gaps in the concrete pad can also contribute to the problem.
If you have any pad that moves up during the winter, you have a water problem!
Once a pad is mudjacked, will the mudjacking material easily erode away?
No! Mudjacking material will last the life of your concrete pad. All concrete pads are supposed to be backfilled properly so water doesn’t have easy access underneath. If water can’t get under the pad, the material can’t erode.
When raising a pad, it’s important to fill all the voids under it?
It’s very important to try to reduce the amount of voids under any pad when raising it. A pad is more likely to settle again when it isn’t filled properly. It also makes it easy for water to flow under the pad, increasing the chance of re-settling, or causing it to heave in the winter months. Once water is under a pad, it’s hard to tell where that water travels. It can easily find a path back to your house, which then can contribute to a leaky basement or structural problems. Voids under a pad make it easier for it to crack in the future because the weight of the concrete isn’t evenly distributed on the ground.
Unfortunately, some concrete raising companies don’t understand this problem so don’t worry about filling voids under a pad.
What’s the chance of raising a pad too high or ending up with more cracks in the pad?
There’s always a chance of raising a pad too high or unnecessary cracks occur while it’s being raised. Someone with experience should be able to minimize these problems.
Some pads are more subject to cracking during raising, because they were poured less than 4 inches thick, or weak concrete was used when the pad was built. In those cases, it’s possible to end up with cracks in the pad. Even if a pad cracks while raising, a good concrete lifting company will usually be able to minimize the effects of the crack and not create a trip spot. Cracks in concrete can happen if the concrete being raised doesn’t have free movement, or too much pressure is applied to one area when lifting the concrete. Caliber Mudjacking has the experience and knowledge to minimize these problems.
Can you raise a pad with hot water heat lines in the concrete?
Yes, we have the equipment and knowledge to detect hot water lines in concrete, making it no more difficult to raise a pad with hot water heat lines than without.
I need my interior concrete floor raised. What’s the chance of hitting a plumbing or electrical line under the floor?
The chance of hitting a line under an interior slab is far less when mudjacking the pad compared to raising it with Polyurethane Foam. With mudjacking you only drill through the concrete once. The holes are only drilled to the bottom of the pad, not into the sand base, making it unlikely to hit a any line.
When raising the pad with Polyurethane Foam, foam is injected under the pad, and is done several times until the pad reaches its proper elevation. Each time you inject in a hole that was already used, it must be re-drilled. Each time a hole is re-drilled, the bit goes deeper into the sand base to get past the previous layer of foam. This increases the chances of hitting a line under the floor. Regardless, prior to raising an interior concrete pad with lines under the floor, it’s smart to have it marked out.
Why should you hire Caliber Mudjacking Ltd to raise your concrete pad?
- Caliber Mudjacking is a family-owned business and has been raising concrete for the last 28 years.
- Caliber Mudjacking Ltd has been a member of the Better Business Bureau for the last 33 years with zero complaints from customers.
- I, Kurt Lummerding (present owner), have been raising concrete for 19 years.
- I, Kurt Lummerding, am a red sealed journeyman carpenter who has the experience and knowledge of how buildings and concrete pads are constructed.
- We have the equipment, experience, and knowledge to raise your sunken concrete. We have raised a wide variety of jobs in the residential, commercial and industrial markets.
- I take pride in my work, and try to raise and fill every job as best possible, whether I’m Mudjacking or using Polyurethane Foam to raise a pad.
- I believe experience and honesty do matter in the concrete lifting industry.