If you’ve noticed some of the concrete slabs on your patio are sinking, there’s usually only one reason – there isn’t enough support underneath it. But how does this happen? It could be that dirt and water have accumulated underneath through a tiny gap. Or it could be that the concrete was somehow accidentally damaged.
Whatever the reason for the underlying support becoming compromised, it needs to be fixed as soon as possible. If not, it could lead to further damage down the line or, even worse, somebody could end up hurting themselves on it.
Luckily, there is a very simple fix and it comes in the form of foam. Even better, it takes a very short amount of time to do (under an hour in most cases) and you don’t even need any specialist equipment.
Below, we’ll show you three simple methods to permanently raise concrete with foam. Throughout this article we’ll explain what tools you need and the step-by-step process to each method. We’ll also look at when it’s best to hire a professional contractor, rather than trying to fix it yourself.
Quick Summary
Before we start getting into the intricacies of each method, let’s take a quick summary of pros and cons that each comes with. This will help you identify which method is best for your specific situation and, most importantly, determine which would work best for your budget.
Method 1 – DIY With Pump
This method is best used when you need to lift sunken concrete, but you aren’t able to use a jack. This could be on driveways or porches that are connected to your home or garage.
Pros
- Super quick
- Less labor-intensive
Cons
- Can cost in the region of $1000 – $1500
Method 2 – DIY Without Pump
An example of the best use for this method would be raising a driveway that you can dig underneath to place a jack. However, to undertake this method you will need to have some experience and be completely confident in your DIY skills.
Pros
- Cheapest method
Cons
- Labor intensive and time-consuming
- Requires precision with mixing and pouring
- Requires the use of a jack to lift the concrete
Method 3 – Hire A Professional
If you feel as though the situation is beyond your capabilities or you have absolutely no experience with this type of thing, it’s usually a good idea to hire a professional. However, it is also the most expensive of all three methods.
Pros
- Doesn’t require any work from you – simply call for an estimate and hire
Cons
- Expensive – can cost upwards of $2500
What Tools Do You Need To Raise Concrete Slabs?
Looking at what we’ve outlined above, you should now have a better idea of which method is the best choice for your project. If you’ve decided that you’re feeling confident enough to do it yourself, there are some tools you’ll need to get before you start taking on the work.
1. Concrete Chalk
You can either use spray chalk or a traditional stick of chalk, it doesn’t really matter. The important thing is that you use it and you’ll need it to make out your spots before you start drilling.
2. Concrete Drill
Don’t attempt to drill through concrete with a regular household drill. It simply won’t be strong enough and you’ll end up damaging it. Instead, invest in a concrete drill. This will make short work of powering through the concrete and creating the holes you need to pour your foam into.
3. A ⅝-inch Masonry Bit
Accuracy is key when it comes to raising concrete with foam, and you also need to make sure you’re only making the holes necessary to the project. A ⅝-inch masonry bit is the best choice when it comes to drilling through concrete, and it will make, quick, efficient work of creating the perfect holes.
4. A Shop Vac
Drilling through concrete slabs is also a messy business! To keep your area tidy and to minimize as much dust and debris flying into the air as possible, you’ll also need a shop vac. These are useful for both wet and dry conditions, so you’ll be able to use it for a variety of other tasks in the future.
5. A Construction Mask
Even with the use of a shop vac, there will still be some dust and debris floating around as you drill through concrete. To stop yourself from inhaling this, make sure you wear a good-quality construction mask. This will also stop dangerous fumes from getting to your lungs once you start pumping in the foam.
6. Hydraulic Concrete Jack
You’ll also need to use a hydraulic concrete jack to raise the concrete to the correct height. This makes it much easier to create a wider space that you’re able to pour your foam into.
7. Pump & Hose
Once you’ve created a space with the hydraulic jack, you’ll need a pump and hose to start filling the area with foam. This pump and hose from BAOSHISHAN is ideal for this and it can also be used with both water-soluble polyurethane solutions and oil-soluble polyurethane plugging solutions.
8. Part A & B Expanding Foam
Perhaps unsurprisingly, you’re going to need foam to raise your concrete with! This two-part expanding polyurethane foam from TotalBoat is ideal for this.
It’s also a closed-cell foam, which means that each cell traps air and stops liquids, water, and oil from entering. In turn, it’ll last a longer time and this means that you won’t have to worry about your concrete sinking again.
9. Fast-Setting Concrete
You’ll also need a fast-setting concrete mix to patch up any holes you’ve made while lifting and filling the concrete.
It’s also a good idea to get a concrete trowel so that you can smooth it out and create a perfect finish.
10. Spirit Level
A spirit level will help you make sure that your concrete slabs are laid evenly once you’ve pumped concrete underneath them. This is another tool that many people forget about, but it’s essential if you want to get it right the first time around.
11. Measuring Bucket
When you start mixing your fast-setting concrete, it can be really tempting to just guess how much you need. However, this won’t do you any favors in the long run and if your mixture is too weak you may find yourself having to repair it pretty quickly. So, to get it perfect every time, make sure you use a measuring bucket.
12. Extra Tools & Equipment
You may also need several other pieces of equipment that you likely already have in your shed or garage. These include a wheelbarrow, gloves, protective eyewear, and a funnel. It’s also worth sacrificing some of your clothes as a DIY outfit, as this is going to be a fairly messy job!
Step-By-Step Guides
Once you’ve got all of the above equipment sorted, you’ll be able to start getting on with raising your concrete slabs using foam. Below, we’ll take you through a step-by-step guide for each of the three methods we’ve outlined further above.
Before starting though, it’s a good idea to ask a friend or family member to help you with the job. Raising concrete single-handedly can be a pretty laborious process and an extra set of hands isn’t only useful, but they can be essential. Of course, if you’re hiring a professional, this isn’t something you need to worry about.
Another thing to keep in mind when following any of the methods below is that you shouldn’t attempt to do it on a rainy day. The main reason for this is that wet conditions aren’t safe to work in. Moisture can also sink into the soil underneath, and most foam will take a longer time to set in rainy weather.
Instead, wait for a day when you know it’s not going to rain. Ideally, this should be followed by another dry day.
Method 1 – DIY With Pump
If you’re looking for the easiest way to permanently raise concrete using foam yourself, this is the best method to choose. It can be pretty expensive if you’re working across a large space though, and you may need to have a budget of $1000 – $1500 available to do it.
Tools & Materials You’ll Need
- Concrete Drill
- Hammer
- A ⅝-inch Masonry Bit
- Wheelbarrow
- Stiff-Bristled Brush
- Spirit Level
- Shovel
- Measuring Bucket
- Gloves
- Eye Protection
- Fast-Setting Concrete Mix
- Part A & B Expanding Foam
- Pump & Hose
- Grout Bag
- Cement Trowel
- Funnel
Process
Step 1: Clear the Area
The first thing you need to do is make sure the area is clear and ready to work on. Remove any debris such as leaves, sticks, and loose rocks, then sweep the area with a stiff-bristled brush. If you’re lifting a driveway that is flanked by grass, remove 1ft-2ft before you start undertaking the work. Collect all of the debris, grass, etc in your wheelbarrow.
Step 2: Locate & Mark
Take your spirit level and lay it across your concrete slabs, working in small measurements until you find where it begins to dip. Once located, take your chalk and mark the spot. Continue moving forward with the spirit level until the area starts to rise again, then mark this with your chalk.
Doing this will give you an accurate measurement of the area you need to work on and, ultimately, you’ll save loads of time and effort.
Once you’ve got the two markings in place, join them together by making several new chalk markings at 6-inch intervals. This will end up looking like the markings along a ruler. Each of these new markings will indicate where you need to drill.
Step 3: Drill & Vac
Now, take your ⅝-inch masonry bit and attach it to your concrete drill. Select the lowest setting possible and, starting with your first chalk marker, start drilling slowly into the concrete.
It’s important not to rush this or apply too much pressure as this could cause the concrete slabs to break. Instead, let the gravity and the weight of the drill do the work and, if you feel it needs a little more pressure, gradually press down while your drill.
Another reason why you should only allow gravity and the weight of the drill to do the work is that too much pressure can cause the drill bit to overheat and dull quickly. If this happens, you’ll be left with the expense of having to replace it.
Repeat this drilling process for each of your chalk markings. This could take some time depending on how large the area is, but it’s worth exercising patience and doing it correctly.
Use your shop vac to collect any dust and larger pieces of rubble as you go, as well. Don’t discard it, though. We’ll use this later when it comes to patching the holes up.
Step 4: Add Your Filler
Once you’ve drilled through each of your chalk markings and you’re satisfied with the result, it’s time to start adding the foam. Start by grabbing the hose from the foam pump injector and place it in the hole that sits at the top of the slope.
Again, it’s important to do this as slowly as possible. Take your spirit level and lay it across the first slab, keeping it firmly in place as the foam is pumped in. As soon as it starts to level up, turn the pump off and remove the hose.
It’s important to remember here that foam expands as it sets. This is why you want to stop pumping it in as it starts to become level, instead of letting it get completely level. Put simply, as the foam expands, it will continue to level out the slabs until they are perfectly even.
Move down to the next hole, place the hose inside, and turn the pump on again. Repeat the same process with your spirit level, making sure you turn the pump off just before the slabs are perfectly level. Keep doing this until you’ve visited each of the holes with your pump.
Step 5: Fill In The Injection Holes
Once you’ve injected the foam through each of the holes you’ve drilled, you need to reseal them. Take your fast-setting cement and mix it with some of the concrete dust you’ve collected in your shop vac using your measurement bucket.
This will allow you to create a strong seal across each of the holes while simultaneously ensuring that each of the holes matches the rest of the slabs.
Add water as per the instructions on the fast-setting cement and mix. Once it’s ready, take your funnel and fill a grout bag with the concrete mix. Inject this into each hole, smoothing over and removing any excess with your cement trowel as you go.
It’s essential that you remove this excess before moving onto the next hole. The nature of fast-drying cement is to dry quickly. Leave it too long and you’ll be left with an unsightly lump of concrete on your slab.
That’s all there is to it! Follow these steps and you’ll have beautifully level concrete slabs that look and feel brand new in just under an hour! The foam and concrete should be dry within an hour, but it’s a good idea to park elsewhere or ensure nobody steps on your concrete slabs for 24 hours afterward, just to be safe.
Method 2 – DIY Without Pump
As we’ve explained in our quick summary above, this is the cheapest method for permanently raising concrete slabs using foam. However, it’s also the most labor- intensive. With this in mind, it’s a good idea to run through the steps before you start undertaking the work.
Again, make sure that you don’t attempt this on a rainy day either. The moisture can seep into the soil below and it will take a much longer time for the foam to set.
Tools & Materials You’ll Need
- Concrete Drill
- Hammer
- A ⅝-inch Masonry Bit
- Wheelbarrow
- Stiff-Bristled Brush
- Spirit Level
- Shovel
- Hydraulic Concrete Jack
- Gloves
- Eye Protection
- Fast-Setting Concrete Mix
- Part A & B Expanding Foam
- Pump & Hose
- Measuring Bucket
- Funnel
- Grout Bag
- Cement Trowel
Step 1: Prepare The Area
Take your stiff-bristled brush and thoroughly sweep the entire area that you’ll be working on, collecting any debris, leaves, and loose rocks in your wheelbarrow as you go. If there is grass or mulch flanking the side of your concrete slabs, remove 1ft – 2ft. This is where you’ll be digging and inserting the jack.
Once the area is cleared and prepared, gather all of your tools together in a place where you’ll have easy access to them.
Step 2: Locate & Mark
Slowly work your way down the concrete slabs with your spirit level, moving in short intervals until you find the area where it begins to dip. Once located, take your chalk and make your first mark.
Keep moving forward from here, measuring with your spirit level as you go, until you reach the area where the concrete slabs start to level out again. Make another mark here, then join each mark together with several new markings placed at 6-inch intervals. This should look like the markings along a ruler when you’re done.
It’s extremely important to make sure that you get each marking as evenly spaced as possible. This is because these marks will act as indicators for the holes you’ll be drilling and pumping the foam into.
Step 3: Drill & Vac
Once you’ve marked out your injection sites, take your ⅝-inch masonry bit and attach it to your concrete drill. Place the drill on top of your first marking and, using the slowest setting, start drilling into the concrete. Do not apply any pressure to the drill, simply allow the weight of the drill and gravity to push it downwards.
The reason for doing this is because too much pressure can cause the concrete slabs to crack, in which case you’ll need to replace them entirely. It can also cause the drill bit to overheat, which can lead to premature dulling.
Once you’ve drilled your first hole, move onto the next and repeat the process until each hole has been drilled. Make sure you clean as you go using your shop vac, reserving some of the dust you’ve collected in the chamber of the vacuum. You’ll need this later for resealing the slabs.
Step 4: Raise The Slab With Your Hydraulic Jack
Next, take your shovel and dig a small hole at the side of the concrete slabs that the jack can sit securely in. If this isn’t possible, you can skip this step.
Once in place, insert the jack underneath the first slab so that it is raised slightly off the ground. The reason for doing this is so that the foam can expand to a perfectly even level. Even though its expanding properties will do most of the work, it’s good to give it a helping hand if you want perfect results.
Step 5: Mix Your Filler
Once the hydraulic jack is in place, you can start preparing the foam. Start by taking a measuring bucket and mixing both parts together to make a test mix. It can be tempting to skip this step, but it’s essential to do it as this will give you a clear indication of how quickly the foam will rise and set.
Once you know how the foam you’ve chosen is going to act, you can start preparing the mix properly. Combine 1 gallon of Part A with 1 gallon of Part B, mix for 15 seconds, then pour into the pump using a funnel.
Next, insert the hose into the first hole and slowly pump the foam in. Lay your spirit level on the slab and, just as it is about to reach an even level, turn the pump off and remove the hose.
You now need to wait for the foam to dry. As it expands, it will continue to level out the slab, and this is why you need to stop pumping it in just before it reads as level on the spirit level.
Once it’s dry, remove the jack and place it underneath the next slab. Repeat the mixing, injecting, leveling, and drying process for each slab until you’ve visited each of your holes.
Step 6: Fill In The Injection Holes
Once the foam is dry and you’ve triple-checked that the affected area is now perfectly level, you can fill in the injection holes.
To do this, take your fast-drying cement and mix it in a measuring bucket with some of the dust you collected in your shop vac when drilling the holes. Mixing these together will help ensure the holes match seamlessly in shade with the rest of the slabs.
Add water as per the manufacturer’s instructions and mix together, then pour the fast-drying cement into a grout bag. Fill in each of the injection holes, making sure you smooth over and remove any excess cement as you go. This will stop unsightly, uneven lumps from forming on the surface of your slabs.
Once that’s done, you’re finished! The result is perfectly even concrete slabs that are well-supported from underneath and highly unlikely to dip again. The concrete will be safe to walk and park on an hour after everything has dried, but it’s a good idea to give it 24 hours to settle properly.
Method 3 – Hire A Professional
There’s no denying that this is the most expensive method. A professional contractor will charge you for their time and for the materials used, which can be in excess of $2,500. However, costs aside, hiring a professional does come with certain benefits.
First of all, you don’t have to worry about doing the work yourself. This is particularly important if you’re not feeling too confident about doing, or if you have a pretty bad track record when it comes to DIY!
You also don’t have to worry about sourcing the tools and materials you need to do the job. Your professional contractor will come equipped with everything they need, and you won’t need to find space in your garage for cumbersome tools when it’s done!
Finally, you simply get better peace of mind when you hire a professional to raise your concrete slabs using foam. There’s no room for self-doubt because you aren’t doing the job yourself! Instead, you’re tasking somebody who has probably done it a hundred times before with it.
Of course, there are some things you need to think about when it comes to hiring a professional contractor. First of all, check how much it’s going to cost. Don’t be afraid to ring around and collect different quotes. You may find that you’re able to find somebody who can do the job just as well as someone who was charging twice as much!
Check out any reviews the contractor or the company sending them has, too. If they’re mostly positive, you know you’ll be getting someone who will do a good job. If they are negative or something doesn’t quite seem to add up, it’s best to go with someone else.
Finally, check to see if they are qualified for the job! A cheap quote can seem tempting, but this doesn’t necessarily mean they know what they’re doing.
Final Thoughts
There you have it – three simple methods to permanently raise concreted using foam. Some are slightly harder than others, but one thing that remains is that they aren’t too difficult. All you need is the proper tools and materials, as well as some time and patience.
Get these things in place and you could have perfectly level concrete slabs in just a few hours. And, of course, if you’re not 100% confident, you always have the option to hire a professional.
