Damages and Basic Care

Damages: How they Happen

Salt/ De-Icer/ Fertilizer

Are used primarily to melt ice on roads or walkways. The problem occurs when the ice melts, the water then absorbs into the concrete due to the salt keeping it in liquid form. If the temperature drops below the freezing point of the salt/water mixture, it freezes, expands and like some type of annoying magic, your flat work starts falling apart.

Some don't use de-icer, but when you park your car above un-heated concrete, the heat from tires and motor cause the salt under your car (from city salting) to fall onto the surface, and further melting it into the concrete. The motor loses all heat in an hour or two, water freezes and the damage mentioned above happenes all-over again.

You can notice this on driveways where a clearly corroded tire path is visable along with a bigger area right under where the motor of a parked car would be.

Pervention- To avoid this, you can either not park on driveway for first couple of winters not usually an option for most of us, use parking mats, sealing right before winter helps or by keeping your vehicle in a heated garage. 

Ground Movements- Up or Down 

Upward Movement

Frost/ Water- I say frost/water because one doesn't work without the other, it's when winter sets in, the vehicle traffic or foot traffic pushes the frost downward, causing the moisture in the soil to freeze and expand, the more moisture or water the more expansion or lift. I have seen driveways lift over six inches and rip stucco off of houses, and even separate a garage from a house that it was once attached too. Caused by water flowing from eaves or garages migrating  into cracks between garage floor and driveway.

Prevention- First before pouring any cement make sure any door jambs or frames that are sticking out have been protected by putting a material such as styrofoam under, to keep concrete out from under the frame, this will allow movement, we also recommend NOT doweling any "floating" concrete such as driveways or sidewalks to ANY permanent structure (like your home), unless using a void form and piles application.

To avoid ground movements keep all water away from your buildings, usually raising grade or dirt around the house to increase slope will solve this problem. You can also extend eve drains in fall to get water a little further. Avoiding pooling of water near foundations or basements will help save your house from excessive pressure in winter, enough to damage walls! Sealing any cracks that water can seep in ie. between garage and driveway. One liter of water can split a solid rock the size of a small car, so if the ground along the whole side of your house is wet with an amount of 100 liters or more, imagine what can happen, nothing will stop frost 100%. At least noting the average joe can afford. The best thing you can do is keep ground near building as dry as possible and keep running water away- no puddles-.

Downward Movement

Is when the ground drops down or settles, this is due to improper compaction. The main issue for this is in new home construction. If the fill was just dropped in, the ground will drop 1-3 feet over 3-5 years depending on the amount of water it sees. Water is great for settling the ground, however if using water to help drop ground around your house make sure to stop wetting the ground at least one month before winter to allow the ground to dry completely before winter. Some new garages are being built on footing and walls so this adds to the issue of settling, more when people want driveways in the first year or two or before possession date. Compaction can be done, but don't be fooled by the guys who pull out a little 40 lb plate tamper and run the top twice, this does nothing. If clay, it has to be dug out, dry to proper moisture, then roll with a sheep leg type packer in maximum 1 ft lifts depending on the weight of the compactor/ roller. Once the ground is packed to 100% from dig up to surface, then and only then it will not settle. Most can't or don't want to afford the extra for this base work, in truth the 2000+ it costs upfront may vary well save you 10,000.00 or more in the first 10 years.

"If we are hired for full base work we guarantee no ground settling" ( dropping)

Hydro-static pressure

Is when the water tables rise, the new water level will sometimes expand certain soils, enough to seriously damage slabs or buildings they are connected to. Water can push up floors over years due to pressure if the source is strong enough, such as artesian wells, or fast rising water, usually seen in older basements where the drainage systems are not installed and the water pressure or expanding ground, force the floor upwards.

Another example is when pits in garages or shops have holes, drain into ground and the floor heaves. This becomes a lot worse if un-heated due to frost expansion will now play a factor and the water is it's fuel for expansion, more water more expansion.

Prevention- I have heard of the use of exterior sump pump being installed, if they work, I do not know. It's basically a well, put on your property that you keep pumping out to lower the water table. The theory is good just have no experience with them to say how effective they are.

I would warn that water tables are sometimes different not more than 20 feet away due to gravel veins along clay. The clay will not accept water like gravel, so sometimes you can dig a hole 10 feet deep and have no water but move 20 feet over and you could have 5 feet of water in that hole and the other remains dry.

Basically if you are experiencing major water leakage into your house you may want to try and figure out best course of action before spending lots of money on project. Would be a shame to spend 5-10 thousand on exterior sump or something like weeping tile to find out it was a leaky water main.... usually keeping proper drainage, to keep water as far away from your home or building will stop most problems or at least help.

If you have good drainage on exterior ground but experience water in basement floor if sure it's not leaky plumbing I suggest a interior weeping tile done properly this will last forever and take any water coming in back out.

Seismic- If the ground wants to move it will move, frost can split 12 inches of concrete, earthquakes break anything they want..... though hopefully don't have to worry about that here in Saskatchewan.

Cracking

Ground movements- As explained above water causes movement and concrete cracks more than likely not where the cut is. This mainly happens in winter, the concrete is frozen to the ground basically stuck there, so when the ground moves due to freezing it breaks the cement where ground decides to move.

Poor mix- If to much sand is in the mix it can cause concrete to crack more than usual, curing compound could help but probably not. If it's bad enough cracks will occur over every piece of rebar. This should not happen, no matter how wet or dry it was placed.

Heat or shrinkage cracks- Caused from letting the concrete dry out to quickly, curing compound should stop these cracks dead in their tracks. To much water, I've heard of it, but never actually had it happen and I have poured some pretty wet concrete. More often than not other factors play a role in assisting cracks to form, lots of sun, dry base ect.

Vandalism/Damage by other- We take no liability for animals, insects or vandals. A big dog can ruin concrete fast and if it's hard enough may not be able to fix it properly same with kids, birds or anything that decides it wants to walk or land on the cement. Keep all animals locked up, maybe even take precautionary measures such as setting up temporary snow fence or sit and watch for potential trouble for the first 4-8 hours after we leave.

Owner Operator Damage

Abrasion- Concrete is hard but not indestructible! Rocks in tires or any other type of hard debris when ground into surface will damage it. As stated in cleaning the best way to keep your concrete protected is by keeping it clean of anything that can damage it.

Impact- As above not indestructible drop something hard or heavy on surface and it's probably going to damage it, you might not see it for a long time. Surface strength can be increased by adding floor hardener. Again harder! not indestructible! It can still be damaged.

Chemical- Many chemicals can damage the integrity of the concrete like salt. Almost all acids or other corrosive chemicals that react with ingredients in the concrete. Again damage may take months to years to notice so always ask concrete supplier what they recommend for protecting their concrete.

Installer 

Installation damages include- Dusting is when the surface will just keep throwing dust while sweeping or rubbing it's caused by finishing with to much water.

Marks or ugliness use your own discretion but it should look good not unsightly.

Improper slope is when the water runs to the building and not away. This should be replaced by the installer. That does not mean when the frost pushes up 2 or 3 years later, that the installer did a bad job it means you have ground movements happening.

High or low spots are when you have a big pool of water(low). Can be fixed, but probably better if it's replaced. Or your walking and the bottom of your heel snags a bump(high). If you could trip on it, it should be taken out. At the installers cost.

Flaking is when the cement is to hard and you are finishing, finisher goes to fill a hole and the paste does not adhere properly, later the paste will flake out, again use own discretion if bad enough you may want to replace at installers cost. This can also be caused by dust from the wind (flaking can also be caused by salt and not to be confused with shale rock or popping below).

Supplier

Faulty concrete comes in a few forms like wrong mix, improperly mixed or faulty design.

Wrong is when you order one thing and the supplier sends another(the wrong stuff), this should be replaced only if it causes a threat to the integrity of the concrete that's supporting something use own discretion. Replace at cost of supplier.

Improperly mixed is when cement comes out of the truck and there are streaks of gravel or lumps of cement powder. Can be fixed by mixing, if truck can not mix it out send cement back. Cost of supplier.

Faulty design is when there is too much sand or other ingredients and mass cracking occurs while placing. This is not supposed to happen replace at cost of supplier. Cracking does occur but it should be every 1-2 feet no matter how hot!

We pour driveways at a 5" slump, with wet cuts every 8-12 feet between expansion joints, have poured on some pretty hot day and windy days, however we also use curing compound and we haven't had issues with shrinkage cracking. On one or two occasions we had cement that cracked while we placed and finished with no reason. We poured on colder cloudy days and cracks occurred before we could even spray the curing compound. This is a solid example of improper concrete.

Shale Rock- Is a soft rock that can be crushed with your fingers it's about as hard as compacted clay. This type of rock will absorb water more than others. In the winter time this becomes an issue due to freezing and salt use from cities. The term used is popping, if there is a lot of shale in the concrete your driveway or unheated concrete can literally disintegrate over a few years. There is really no way to tell how much is in the mix without sampling gravel supplies prior to mixing the concrete.

It boils down to concrete plants order gravel from various suppliers the shale rock is found more in some areas a lot more than others, so as they bring in gravel for the concrete mix suppliers bring loads of gravel with lots of shale, little or even none. I believe this is how you get some driveways that suffer from popping and some that do not or very little.

Weather

We take no liability for the weather 

Rain- Every concrete guys nemesis. Takes but a second and the surface can be gone. If rain comes we do everything we can to protect your investment, but there are no guarantees. We also check four different weather stations prior to pouring and still get caught in it sometimes. Respectfully I try to pour with less than a 10% chance of rain or no chance. If you feel you know best we will pour but also charge to cover with no certainty that covering wont damage your concrete also. If it comes on a day I pick we cover for free client pays for covering material and we do our best, but still with no guarantee. Some times the wind will not agree with covering.

Hail- Can damage concrete up to a month old, should hardly be noticeable at a month old. Two weeks and if the hail is big enough it will pit or dent the surface, which will usually fall off after a short period of time. Couple of days old concrete can be taken off the rock, total loss of surface. If your job is in serious risk and you have the time to do something about it, cover it with something that will avoid the impact of the hail. Insulated tarps, blankets, geo-tech even sand or dirt. If you use plywood or anything hard don't drag it across concrete and remove as fast as possible to avoid staining.

Wind- Can damage by blowing debris onto concrete and the stronger the wind the bigger the debris. More often than not the wind plays a factor in everything. Drying to fast when pouring, blowing stuff on when finishing and when accompanied by rain or hail it can seriously leave you disliking it while trying to cover it up from the rain or hail. 

Basic Care

Placing - Curing - Sealing - Cleaning

Placing- I believe placing is one of the most important parts for surface strength many factors contribute to strong concrete. Slump don't pour to dry or to wet, if you want a number '5' is the magic one. I have poured concrete at a 1-2" slump to a 7-8" both are not good and can cause failure in the project. To dry and it wont adhere properly to itself without lots of vibrating, which is fine for walls and anything structural that you expect to vibrate just not on residential flatwork. To wet and run a greater risk of shrinkage cracks or surface damage, like dusting. A 5" slump when placed and finished properly along with a strong concrete is perfect for flatwork. Too much water when finishing can cause dusting and waiting to long can cause peeling of the surface or flaking not to be confused with shale. Temperature is a big factor too, to cold the concrete will take longer to set which is good for curing but bad if it rains 6-10 hours later and to hot it will dry fast and there is a risk of shrinkage cracks. Curing compounds can reduce the risk of this but there is no 100% guarantee.

Cure and seal- A few different types, one time application that is applied after last pass or completion of work. Although where shale rock is present you should wait 30 days. READ PRIOR OR TALK TO SUPPLIER.

Curing compound- This is applied to cement right after finished to prevent shrinkage cracking. Comes in a few different selections. Many are good however some leave a permanent discoloration especially on colored concrete. Warning if supplier states no stain get it in writing and when or if it stains tell them to come clean or replace!

Covering or Hydro cure- There are many methods covering with poly, curing blankets, burlap sacks, insulated tarps(probably best), or submerging(flooding and kept submerged for duration not sprinkler on and off for a couple of days). Plus probably 20 others I haven't even heard of. I light of all this I say ask the supplier what they recommend for their cement. Keep in mind different methods take different time and yield different results.

Sealing- They say sealer protects from everything and it probably does, however it does not stand up to abrasion very well so if your driveway has gravel or small rocks on the surface they will scratch threw and the sealer is now gone in that spot allowing water to penetrate. I always say ask concrete supplier what they recommend for their concrete. Always wear proper protective equipment, stay away from foam rollers as they will dissolve as will styro foam and most shoe bottoms. Be courteous to neighbors and watch over spray, at very least you don't want to replace windows or anything else that the wind blows sealer on.

Cleaning- Perhaps the most important step of keeping your concrete healthy. Rocks and debris left on concrete cause abrasions when walked or driven on. Causing scratches, chips or early surface erosion. Gasoline, xylene class 3 of 5 dangerous chemical(found in nail polish remover scary because its most easily absorbed into the human body threw cuticles and under nails), motor oil, brake fluid or several other garage chemicals will dissolve most sealers rather quickly. So do not spill gas on a sealed driveway it can cause blistering of the sealer and staining of the concrete.