3 Kinds of DIY Concrete Mix
July 10, 2009
Got a small patch job or chipped a corner off your slab? Maybe you just have a small retaining wall or foundation that you want to seal a crack in. It’s just a small job that you can do yourself and don’t want to spend the time or money farming out to someone else. For this type of job you may want to consider a DIY concrete mix. It’s quick, cost-effective, and you save tons of money on the labor.
I am going to go over 3 types of bagged concrete and their various applications and a quick overview on their intended uses. First off, the Concrete Mix: This should be used for larger areas you already have formed or cleared with a depth of @ least over 1”. A perfect example of this is a small patio slab or maybe some sidewalk repair. Setting posts, pouring stairs or any larger type concrete project is the recommended use for this product. It’s easily finished with a long working time, but will harden quickly after that and be open for traffic in 2 hours. CementAll grout is great for patch jobs, too. RapidSet’s Mortar Mix is great for when you need to repair a wall or install windows. General concrete repair and stucco repair are 2 more possible uses. All 3 of these products are interior/exterior products and can be used just as easily in your home as on your deck.
For any small to medium size concrete project around the house, you can make do with any of these 3 products. They are great quality, durable, and aren’t prone to cracking. These are only guidelines that are laid out, and any manufacturer’s recommendations should be followed to get the maximum benefit from your concrete.
Concrete Information For Calculator
July 10, 2009
How To Mix and Install Self-Leveling Concrete
June 19, 2009
Recommended Tools:
1. Mixing Drum – should be large enough to accommodate 2 or more bags of material and water.
2. Spreader (Application tool used to gauge thickness of material to be placed)
3. Steel Smoothing tool
4. ½” heavy duty drill (650rpm min)
Surface Preparation:
1. Make sure concrete substrate is clean and all grease, oil, asphalt, sealing and curing and latex compounds have been removed. Any possible contaminant should be disposed of, removed or cleaned. Depending on the condition of the concrete mechanical cleaning may be necessary to expose sound, clean concrete.
2. Self-Leveling concrete requires a primer to be applied prior to application. This is to ensure a good flow and well-finished surface. Apply the primer with a clean soft-bristle push broom. Use of a paint-roller is discouraged as the broom application allows the primer to get into the pores of the existing surface. All areas should be primed and excess puddles should be brushed off.
3. The primer should be allowed to dry to a tacky, thin film. No less than an hour and no more than a day’s drying time will be sufficient.
Mixing:
1. Measure out the manufacturers recommended water dosage and pour into mixing barrel. Hold back one part (approximately 10%) of the water during initial mixing to minimize powder lumping. Most products mix better with a minimum of 2 bags of product at once unless you will not need that much material.
2. Add dry powdered material into the barrel. If you are mixing using a hand drill it should be turning as you add the concrete.\
3. Mix thoroughly with drill for approximately 30 seconds and add remaining water until desired consistency is reached. Continue mixing for another 1 and a half to 2 minutes to obtain a lump-free mix (this is especially important with self leveling concrete mixes as they are applied very thinly and even small lumps in the mix can mess up the finish as well as other undesirable effects. NOTE: Yellowish foam while mixing or settling of the sand during placing indicates over-watering!
Application:
1. Pour the leveling concrete mix on the slab and spread the material with the spreader. Adjusting the spreader to allow ¼ “ of material to be placed on the substrate is recommended. To obtain the best flow install material at a minimum of 1/8 “ over the highest point in the floor. This method will typically result in an average thickness of ¼ “ over the entire floor. Typical product flow times average 10 minutes at 70 degrees. Once the initial pour has been established, product can be feather edged.
2. Immediately after placement, smooth the material with your steel smoother. This will break surface tension on the concrete and allow the material to better flow into marks left by the spreader and applicator spikes. It will also leave a finer finish and minimize pinholes.
3. Take precautions to avoid blowing air on freshly placed concrete to prevent plastic shrinkage cracking and other undesirable effects.
4. Typical self-leveling concrete products are ready for light traffic in 4-5 hours at 70 degrees though this depends on humidity and substrate temperature.
5. As always, follow proper curing guidelines to get the most out of your project!
Quick and Easy Slab Leveling
June 19, 2009
Let’s say you’re sick of the cracked, chipped uneven basement floor in your house. It is unsightly, unsafe, and is doing nothing to improve the value of your home. Not only that, but your wife is complaining because she keeps tripping and dropping the hamper on the lopsided floor in the laundry room. You’re also getting tired of spending all your time and money driving your kids to the emergency room because of twisted ankles and sending out search parties because they keep getting lost in the crevasse sized gaps. You want to put tile, carpet, or hardwood down but you can’t. It’s just in too poor of shape. One way or another, you’re looking at concrete resurfacing and slab leveling as the first step. Sounds like an expensive and tricky project. You should probably just forget it, or call a contractor right? Well before you pick up the phone book I urge you to consider this: self-leveling concrete. With this product, a basement floor leveler project becomes much simpler.
Before you can install anything on top of the old floor, you’ll need to make sure its level. This is especially true for tile leveler and wood floor leveler jobs. Start off by grinding down any high spots and use a concrete patch mix or concrete repair mix for any spots more than ¼” below level. An easy way to check for high and low spots is to run a 4’ bubble level over the entire slab. With this accomplished, it’s almost time for your flooring leveler (or subfloor leveler). First, make sure your surface is clean of debris, oil, grease, sealers, contaminants, and loose material. When your floor is cleared of those things it is time to apply your primer. This is necessary for a good bond between the floor leveler compound and the subsurface. It will also improve the flow of the floor levelers as well as the final concrete surface. Apply the primer with a clean push broom or a medium to thick nap paint roller for larger areas. By using the push broom you are allowing the primer to seep into the pores of the material you’ll be covering. Make sure all areas are primed and excess puddles of the primer are brushed off. When the primer has dried to a tacky film (between 1 and 24 hours), you are ready to begin laying your concrete.
As a general rule, 50 pounds of floor leveler cement will cover 50 square feet at 1/8” thick. For the mixing and application of the product you will need a mixing container, a spreader which is used to gauge the thickness of the placed material, and a smoothing tool to break the surface tension of the concrete. A 1/2” heavy duty drill (650 rpm min) with a paddle mixer extension will also help with the mixing. Barrel type mixers should be avoided if possible. Follow the manufacturer’s recommendation for mixing and water requirements. You should also hold back 1 part (~10%) of your water content to minimize material lumping during mixing. After 30-60 seconds of mixing you can add the water you have held back. When a minimum of 2 minutes into your mixing time has gone by, it is time to lay your new floor!
Pour your leveling concrete mix on the floor and work it around with the spreader. A well-batched plaster mix will spread out evenly over the area to a nice, level surface. Most manufacturers recommend that the spreader gauge is calibrated to allow ¼” of material to be placed. Aim for a minimum thickness of 1/8” over the highest point on the floor which will result in an average thickness of ¼” over the entire floor. After the initial pour, immediately smooth the material to break the surface tension. This will minimize pinholes and allow the material to flow into any marks or gaps left by the spreader. Any featheredge you may wish to add should be done now. Most self-leveling products will be ready for light traffic in 4-5 hours under normal temperature and humidity conditions. If you’re planning on using the new surface as a sub-floor for tile, carpet, or hardwood allow it to set for at least 24 hours before further work. As always, follow appropriate curing methods for best results!
The importance and effects of curing concrete properly
June 19, 2009
So, you’re concrete project is almost completed! You’ve planned it, prepared it, formed it, poured and finished it. As you complete the final pass with your trowel, you’re already imagining how it is going to look when it’s dried. All that’s left to do is clean your tools, grab a beer, and enjoy the fruits of your labor, right? Not necessarily. Whether it’s a small patching job, installing a new driveway, or building a highway; a few additional steps and precautions after finishing you can ensure your next concrete project will reach its full potential.
Curing
In the world of concrete, the maintenance of the drying and setting process is referred to as curing. The purpose of curing is to keep adequate moisture content and temperature as soon as the concrete is placed and finished. It is one of the most important (and overlooked) steps and can have the greatest effect on the final outcome. Properly cured concrete can have significantly superior properties compared to concrete left to set after finishing. Sufficiently cured concrete will exhibit greater durability, wear resistance, and gain strength faster. Cured concrete will also have better resistance to deicers and freeze/thaw damage. Improperly cured concrete can be subject to plastic shrinkage cracking (loss of moisture from fresh concrete) and drying shrinkage (loss of moisture from concrete that has set) among other undesired side effects.
Hydration
Concrete sets and reacts with water in a chemical process called hydration. The components of cement in concrete react with the water and this causes the cement to congeal and harden. Hydration won’t occur under every condition, however. If the internal humidity of the concrete falls below 80% or the temperature is below 14 degrees Fahrenheit, hydration will stop completely. The hydration process also produces heat, and it is important to maintain less than 35 degrees temperature difference between the exterior and core.
Curing Methods
Curing methods, simply put, involve protecting the exposed surfaces of any concrete mass from excessive evaporation or temperatures and maintaining an adequate supply of water for the hydration process to take place. Though concrete will continually cure and hydrate throughout its life, the process is most active in the first 7 days after placement. That is why during this critical time it needs to be protected. There are 3 methods you can employ after laying concrete to properly cure it. One method is to seal in the water already present in the concrete from mixing. This can be done by spraying a curing compound after it is finished which will create a membrane on the surface that reduces evaporation. Covering your concrete with waterproof paper or polyethylene sheeting will also have a similar curing effect. The second method involves supplying additional water to the concrete as it hydrates. This can be achieved by ponding or immersion of the concrete, spraying or fogging the surface of the concrete throughout the curing period. Saturated wet coverings, such as a moist sand or wet burlap covering can also be used. This method of curing also cools through evaporation which can have some advantages during hot weather placing. The final method is the most involved and complicated. To supply heat and additional moisture electrically heated pads and forms (mostly used in precast concrete), heating coils, and even live steam is used.
The method you choose for curing concrete will vary according to conditions, resources, and availability of materials. Larger projects should have their own curing plan in place before placing begins. Hot and cold weather placement should also have special considerations and precautions in place.
By taking the time to properly cure your next construction project, whether it’s a large concrete slab or driveway to a small DIY concrete mix, you can ensure that your investment will continue to pay off throughout its service life. Though it involves a few extra steps and will prolong the time from placement to use, the long-term benefits far outweigh the relatively small amount of time it takes to properly cure your concrete.