Sub-grade:

As with many home improvement construction projects, what you don’t see is more important to the finished project than what you do see. The preparation of the sub-grade when pouring a concrete driveway is critical, without it, the life of the driveway will be decreased dramatically.

The first phase is to clear the area to be concreted of all grass, tree roots, and topsoil. If you are putting a driveway in a new area of your property or if your property has been recently graded the underlying earth must be compacted. Once the earth is compacted, you can add the layer of sub-grade material, crushed rock. A standard sub-grade thickness for a driveway is 4 inches (consult a soil engineer in your area to obtain the optimum thickness) and it is key that the sub-grade maintains an even thickness throughout the width and length. A sub-grade that varies from 3.5 to 4.5 inches will create long-term problems. Do not use the sub-grade material as filler for any low spots.

If you have a 4-inch sub-grade of crushed stone and a 4-inch concrete slab, and you want the driveway to be level with the surrounding ground then you must dig-out 8-inches of soil and earth.

Complete the sub-grade by compacting. Make sure you allow for proper drainage as outlined further on in this article.

Forms:

Wet concrete is enormously heavy! If you are using wood forms, they should be a minimum of 2-inch thick lumber. Drive stakes into the ground at least every 2-feet on the outside perimeter of the form. It is wise to use an easy form release coating on the inside of the form, otherwise you are likely to break away pieces of the concrete when removing the forms.

Steel forms are now available, which maintain their shape. Most construction rental facilities have these forms available.

Concrete Mix:

A standard concrete mix is 2,500-psi. For a driveway, you will want a much stronger mix of 4,000-psi, with a 0.5 water to cement ratio, which provides a denser concrete and hence increases the wear ability. Because concrete is permeable it will draw moisture from the ground that it rests on. By using a 0.5 water to concrete mixture, you will reduce the amount of moisture drawn up which in turn will reduce any efflorescence action on the surface of the concrete.

If you live in a cold climate, order your concrete with air entrainment. Air entrainment provides microscopic air pockets within the concrete which is a place for moisture to freeze without applying undo pressure on the concrete.

Joint Location and Depth:

Joints should be put into the concrete driveway slab after the pouring is complete. In other words, the slab should be one complete pour. If you pour multiple slabs, they will shift and heave independent of one another.

The proper depth of a joint is 0.25 of the thickness of the concrete. If you have a 4-inch thick driveway slab the joint should be a minimum of 1 inch. Place the joints 2 to 3 times, in feet, based on the thickness of the concrete slab. Hence, a 4-inch thick slab would have joints spaced 8 to 12 feet apart. Proper depth and placement of joints will help to prevent cracking.

Drainage:

Providing adequate drainage is fundamental to the overall driveway design. The driveway, when complete, should have a minimum of a 0.25-inch per foot slope. The drainage should be considered when first preparing the sub-grade. If an adequate drainage slope cannot be provided because of surrounding buildings, you may have to consider the installation of a drain to collect water.

Use a laser level to set the slope of the forms.

Reinforcement:

Reinforcement does not prevent cracking. What reinforcement does is to reduce cracking and hold the slab together in the event of cracking.

For reinforcement, you can use wire mesh or steel bars (rebar) placed in a grid pattern. If rebar is used you must tie the joints together where individual bars meet. The reinforcing wire or bars must end up in the middle of the concrete slab and not rest on the surface of the sub-grade. To accomplish this you can rest the mesh or bars on stones or pieces of brick and then after the pour pull the wire mesh up and into the poured concrete.

Finishing:

To finish the slab you must use a bull-float. It is important that you allow the water on top of the concrete to evaporate before you start the finishing operation. Failure to do so can result in a weak surface area because of trapped surface water.

For additional information on concrete slabs or other home improvement projects, visit Renovation Headquarters.

Lots of homeowners find out they have an uninvited guest shacking up in their basement. Ever seen little white fuzzy stuff on your concrete basement floor?

Mold on concrete can take many forms. Concrete is a porous substance, and your basement floor gets a lot of moisture from the ground underneath it.

Usually, concrete foundations have a moisture barrier. But, in some cases the moisture barrier is old or damaged, or it may not have been properly installed.

In arid places like Southern California, Arizona and high altitudes, you may not have a moisture barrier built into your home. You usually don’t need it, but if you have a heavy rain or a spell of humid weather, you’re likely to get that nasty mold growing on your concrete floors.

If you have mold growing on basement tiles or under basement carpeting, the cause may be the concrete underneath. No matter what your mold problem, you have to remove it from your concrete.

A Little Bleach And Elbow Grease

If you’ve got a little mold growing on your concrete surfaces, it’s easy enough to clean up. For little bits of mold here on there, use a solution of water and bleach. 4 parts water to 1 part bleach is usually the recommended formula. You can also find cleaning products designed specifically for mold removal.

Scrub at the moldy spots with your bleach and water until it’s gone. Be careful - that bleach is dangerous stuff. Make sure you have some good rubber gloves and be careful that the bleach doesn’t come into contact with anything else.

Seal It Up

If you have more serious mold problems and a good scrubbing won’t get rid of it, you might try sealing the cracks. Chances are, the appearance of mold on your concrete surfaces is a symptom of a bigger structural problem in your home. There may be cracks in the concrete or walls that allow moisture to come into the house.

Go to the hardware store and look for a waterproofing compound made for this specific purpose. If you’re totally unsure, talk to the clerk and explain your problem. What you want is something especially designed to seal up cracks in your concrete and walls. The compound will come with detailed instructions on how to use it.

Call The Contractor

If you have water wicking up from under your foundation into the concrete, you’ve got a much bigger problem. You may need to call a professional.

What you’ll need to do is take off all the flooring so the original concrete is exposed. This is something you can probably do yourself, but you should make sure to keep yourself safe. Any time you’re dealing with mold, make sure you have good gloves and a mask, and make sure that the mold doesn’t get into any other parts of the house. Even if you’re working in the basement, make sure you have some ventilation going.

Now, you’ll need to have a new top layer of concrete poured. It has to be at least one inch thick. Make sure that the new cement is mixed with a waterproofing compound that will keep down its moisture level.

This is a big job and most of us would have to call a contractor. Check your local yellow pages.

Learn more about removing black mold from shower ceiling on our site. You’ll also find other information such as black mold smell testing and black mold exposure treatment ToxicBlackMoldHelp.org is a comprehensive resource to help individuals to test and inspect, identify health symptoms and removal of toxic black mold.

Concrete Coating and concrete painting

Many home improvement projects will require you using a concrete coating. Concrete is used for a wide variety of purposes in building and construction. Concrete is made up of a mixture of different substances such as cement, gravel, sand and other aggregates, mixed with water. Special caution should be taken to prevent the water in the mixture from evaporating because if this happens, gaps and voids may be left behind which can cause the concrete to weaken and create small holes and cracks in the concrete. Further exposure to water and the harsh elements of the weather may erode the concrete, reducing its strength greatly. Concrete coating is beneficial to homeowners and construction workers alike because it protects concrete from such structural problems.

Where should you use concrete coating?

If you have never used a concrete coating before, you may wonder exactly how it works.
Concrete coatings are special chemical solutions that create an impenetrable coating, or layer on the concrete preventing the transmission of water molecules while at the same time keeping the structure safe. Concrete coating is typically used in filling the voids left from water drying up in the concrete, strengthening the surface due to a coating effective.
Concrete coating is also used on pre-cast concrete used in parking areas, protecting the structural steel body from the effects of water transmission. Salt and other corrosive elements can cause damage to concrete structures, especially in high traffic areas. Concrete coating can be used to prevent and reduce damages in such areas.

What are the advantages of using concrete coating?

There are several advantages of using concrete coating. As discussed above, the biggest advantage is providing protection from water transmission. Another advantage is concrete coatings is also an excellent acrylic crack resistant. Concrete coating conveniently adheres to most kinds of construction materials such as block, concrete, polystyrene, SIPs and ICFs. Concrete coatings are available under different brands and two or three coats should be applied depending upon the kind of construction material used and to the extent of which it needs protection.

Where to buy concrete coating products?

Concrete coating products are available at most home improvement material suppliers. However, for larger projects, it’s advisable to directly contact dealers to purchase such products. Concrete coating products suppliers can be easily located through concrete contractors as well as home building associations. The Internet is also a valuable resource, especially with its multiple websites on such products and applications. The Internet is not only a good source of information on the various concrete coating products and brands available, but also a good way to compare prices. Concrete coating projects are best handled by professional concrete coating contractors because they have the ability to correctly determine the specific kind of pressure withstood by concrete in a particular construction project.

Trevor is a leading home improvement author and writes often for http://www.homearticle.info. There are also more concrete care ideas on that site.