Interlocking expansion (popped out)

mcvane

Hi There.

I live in Ontario, where the summers are hot and the winters are cold.

We just went through a spell of several heavy snowfalls and several times of shovelling through the mess. However, soonafter, we had lots of rainfall that melted most of the snow and now the temperature is hovering around -2 celcius (30 Farenheit).

I have noticed since these down and ups of temperature that about 4 of our interlocked bricks (all together) are stuck out about 2 inches above what they should be. It might be that something has popped these bricks up.

It's not something I need to fix now, but I want to know is this something I should try to fix in the spring when the weather is warmer and perhaps the density of the interlocks have shrunk?

I was considering using a rubber mallot, but didn't want to risk damaging anything right now.

Thanks for your help.

jmb324

Hi...sounds like water got under them and then froze...my slate tile patios do this every winter, several tiles will raise up due to freeze expansion and then once the ground thaws they go back down...sometimes you have to tamper the the ground under them back level once all the freeze temps are over. Here in the midwest its not uncommon to have driveways, sidewalks and foundations move and even crack due to the freeze thaw process during winter. You may find that the bricks sink back on their own once the ground becomes soft. Good luck and Happy New year!

concretemasonry

Slate tiles are totally different than interlocking paving stones that are designed to have a permeable sand setting bed and a proper well compacted base.

Do not over-react and beat on the pavers now. Let the spring thaw comes and let the pavers go go back to where they will.

You now know where the problem is. You probably have a bad base or sub base that collects water and will heave. If this is the case, you may have to remove the pavers and correct/replace the material or change the drainage.

Is it a sidewalk, patio or a driveway?

beranbr

Properly installed interlocking pavers should not typically do this. The typically cause for what you have described is indeed poor base work. Proper drainage is crucial for interlocking pavers to last the test of time. For some reason or another, it sounds like water is not properly draining. If there is lots of heavy clay and the base is not thick enough and/or geo-textile fabric is not used, this may result in heaving. Or if the incorrect material is used for either the base or the bedding sand this can happen. The base material should be a 3/4 modified stone (crush and run) and not granite dust. The bedding sand needs to be a coarse concrete sand and not the type of sand used for mortar or play sand. Many contractors use using granite dust for either base material and/or bedding sand and this is a big problem. Granite dust will compact very hard, however, because there is no large stone it doesn't allow water to drain properly and will retain large amounts of water. This may be the problem. I would wait until the Spring and then check it out by removing the section/s that are in question and look at what is under the pavers. One you should find 1 inch of a coarse sand and then a tightly compacted crush and run base the is 4-6 inches thick for patios and walkways and 6-12 inches thick for driveways depending on where you live. Hope this helps.

beranbr

If the pavers were installed professionally within the last year I would call the contractor and tell them what is going on. They should fix it free if that's the case.