Do you see signs of concrete cancer on your walls or ceiling and are wondering if it’s covered by insurance? Or maybe you are planning on buying a house with concrete structures and this is something you’re worried about?
Both of the questions are valid and I’ll try my best to answer them as well as I can. Concrete cancer is ugly and it can happen in all concrete structures exposed to weather or water.
What is concrete cancer
Before we get to is concrete cancer covered by insurance, let me explain to you what it is and why it happens. I’ve worked for years repairing this sort of problem so I’ve gathered a little insight on it.
So what does concrete cancer look like? Usually when you look at concrete structures, it’s healthy grey surface without any rust on it.
Now when you look at the wall that has concrete cancer, you can see rust on it and usually long cracks or even bare rusted rebar showing on it. It is also called concrete spalling.
Concrete cancer causes
So what causes concrete spalling? It’s caused by the rebar in the concrete. The purpose of the rebar is to increase tensile strength, but it’s also vulnerable to rusting.
It’s also one of the reasons why modern reinforced concrete won’t last thousands of years like the ancient concrete structures.
Now is concrete cancer one of the signs of bad concrete? It might be or might not. Most of the time I’ve had to repair this kind of damage the rebar has been too close to the surface. Under 1 inch or so.
Usually, when you get to a depth higher than that, the rebar is healthy there. What has caused the corrosion is water on the surface and that the rebar has been close enough to be affected by it.
Building defect insurance and concrete cancer
Now it’s time to get to the point you must be interested in. Is concrete cancer, or spalling, covered by building defect insurance? I’m not a specialist here, but it should depend on the severity.
Building defect insurance usually covers you from building defects as the name implies. Now, if your concrete cancer is so bad that it affects safety and structure carrying capacity, it might well be covered by it.
But don’t take my word for it, most of the warranties builders and concrete contractors offer hold only up for a year and some of them don’t even cover concrete spalling on it.
Now insurances are usually there for unexpected damage so they should have some kind of time limit and also a way to measure is the damage something it should cover.
Small concrete cancer isn’t dangerous in most cases. All it could be is a small falling concrete danger.
When on a larger scale when all the rebar is left near to surface to rust or there is too little rebar on the structures for the load it’s supposed to carry would be a lot more dangerous.
So sometimes it is and sometimes it isn’t covered by insurance.
Concrete cancer repair
Now it’s time to talk about is concrete cancer repairable. It is something that concerns us homeowners and people who deal with concrete properties.
The answer is that you can repair it and it isn’t that hard. You just need some basic equipment like a hammer drill, that you can rent, and the proper materials to fix it.
Still, concrete spalling repairs should be done carefully so the problem won’t repeat and if you feel like it is too much, you should consult professionals.
Concrete cancer repair products
If you find out some kind of concrete cancer repair kit, check out if it holds any of the following things.
There should be something to cover the rebar with so that it won’t rust again. Corrosion is what caused all of this so it shouldn’t repeat right?
Now times have gone ahead since I started this kind of work and corrosion compounds aren’t used with all the products anymore. Polymer fiber concrete fix products have become more common and some of them can handle the corrosion without any extra products.
Polymer concrete is one example of a water-resistant concrete product. It’s used at places where water is a problem and you can’t trust normal concrete to hold against time.
Now polymer patching products work a bit like that, but the liquid polymer isn’t always used with them.
The concrete cancer repair cost will depend naturally if you hire help or not, how much you need to repair, and what tools you have.
To make a better estimate, look at the DIY repair guide that is following.
Concrete cancer repair DIY guide
As the last thing, I want to leave here steps to fix concrete cancer yourself. Take this as a general guideline and you should be good.
Step 1: Expose the rebar in the concrete. Take your hammer drill with a chisel head and start hammering that concrete around the rebar.
It should start to come off easily, but what is hard is getting some of that concrete under the rebar off as well. You want the patching stuff to go around the rebar when you fix the sport so you need to get enough off to place your finger under it.
Hammer around the rebar and follow along with it with the hammer drill. When you start seeing healthy rebar that looks like regular steel, expose it 2-4 inches. If it’s deep you don’t have to do more than the minimum.
Step 2: Clean the rust on the rebar with a wire brush. Just brush it until most of the rust is gone.
Step 3: If you have a pressure washer, wash the concrete cancer spot with it. If you don’t have one, use a water hose to get most of the dust of.
Remember how concrete is porous? If the pores are filled with dust the patching compound will naturally adhere there weakly.
So with a pressure washer, you will get as clean as you can, but with a water hose, you can get it pretty clean as well.
Step 4: After the concrete has dried, depending on the product, you might need to use some bonding adhesive on the concrete or not.
The polymer products I use don’t require this, but there are many on the market. My advice is to always follow manufacturer info. They make it for reason and that is maximum adhering and protection using their products.
Step 5: Time to mix the patching product. Follow the manufacturer water to dry mix guidelines so it will be as good as possible. Also, follow how it should be mixed, most of the products will have to sit for 3-5 minutes and then be mixed again before use.
Step 6: If there is no bonding adhesive, just moisture the surface of the patch. Not dripping wet, just enough that it changes color to moist.
Step 7: Start filling the concrete cancer spot with the product. If it’s a ceiling, you might need to first fill it a little and the next day fills the rest. Gravity will pull the patch and it will of the ceiling if you’re greedy.
With walls, follow the manufacturer info on how big patches you can do with a single fill.
Step 8: After you have patched the spot, use your trowel to screed it level with the rest of the surface or float to level the edges.
This will be something that you can’t sand with paper so you don’t want to leave it unfinished. Imagine sanding concrete, it would be as effective.
You can also leave the surface of the patch 1/4 inch under the level of the rest of the wall or ceiling. This way you can use the finishing product on it or the patching product with a thinner layer and finish it with a float to be a smooth surface.
This is the go-to method that I teach to everyone new to concrete patching. Work smart, not hard. You will start to hate life if you have to sand every patch you make.
This got a bit further from is concrete cancer covered by insurance than you probably thought, but as it most likely won’t be I wanted to include the fix in here. This kind of thing usually happens after a few years or after a decade so most of the warranties and insurances won’t cover them unless they are big building defects.
If you want to know how to prevent concrete cancer, the answer would be you need to protect your concrete from the weather. Use concrete coating so the water won’t sink in and if you have concrete ceilings, try to make it so that it won’t get wet.
Water control is the key to preventing spalling. If the rebar can’t rust, it won’t cause concrete spalling. Simple as that.
If you have slabs that need outlets for water, check this guide on concrete coring. It’s a way to make larger holes for something like water pipes that can be used to guide water away from the balcony etc.
If you’re wondering is it safe to buy a house with concrete cancer you have to think how old is the house. If it’s decades-old with only a little spalling, it should be good for decades more.
If there is serious spalling damage you can see with your eye, wonder what else did they do wrong.