Building a walk, driveway, patio, or steps can be a good outdoor project for a homeowner.
* CONSTRUCTION IN GENERAL *
The methods of constructing walks, driveways, patios, and steps have much in common. Local ordinances may apply to these construction items, and so the local building code or department should be consulted. Different types of concrete are required for walks, driveways, patios, and steps. Consult Hamilton Block & Ready Mix for recommendations on the concrete to use for your job.
* LAYOUT AND PLANNING *
~ WALKS ~
The width of the walk depends on whether it is a sidewalk, front walk, or service walk, and may be determined by individual preference. The width of a walk has a subtle bearing on its utility as well as on the appearance of the yard, and thus deserves careful consideration. Walks are usually 4" thick. Walks should be crowned or have a slope of 2% for drainage.
~ DRIVEWAYS ~
Single-car driveways are usually 9ft to 10ft wide, double-car driveways about 16ft to 20ft wide. Drives should be wider at curves because the backs wheels make a track with a smaller radius than do the front wheels. Driveways should also be crowned or sloped at 2% for drainage. The thickness of a driveway for a passenger car should be 4". If vehicles heavier than cars will be on the drive, a thickness of 5" or more is recommended.
~ PATIOS ~
The patio can be designed as a square, diamond, rectangle, circle, or just about any shape dictated by personal taste and imagination. The outline can be adjusted to the shrubs, trees, or layout of the yard. A good rule for determining size is to make it larger than the largest room in the house. The concrete slab for a patio should be at least 4" thick, and control joints should be provided at maximum intervals of 10ft each way.
* SUBGRADE PREPARATION AND GRADING *
Remove the soil to such a depth that the final surface elevation of the slab will be slightly above the surrounding ground level. Remove all top soil, vegetation, wood, large rocks, and all soft material that will not compact readily. Backfill with suitable materials that will provide a uniform sub grade. Level off and compact the loose soil with a compactor, or sprinkle for several days for a uniform density. Sand, gravel, or crushed stone are useful for fine grading. If the soil is clay, replace the clay with 3 to 4 inches of sand for a base and then compact it.
* FORMING *
Side forms are commonly made with 2"x4" boards. Place them to outline the shape you have chosen and nail securely to stakes driven firmly into the ground. The stakes should be no more then 4ft apart and should back up every joint in the form lumber. If the slab is more than 12 feet wide, you may want to use a pipe that runs down the center of the slab for the strike off board to follow as a guide. When the forms are set, check the sub grade to make sure it is the desired thickness of the slab. Pull a template, riding on top of the forms, across the sub grade to get a smooth, uniform depth.
* HOW TO ORDER CONCRETE *
Order no more concrete than you can place and finish within three hours. Order the quantity of concrete in cubic yards, remembering to make a 10% allowance for uneven sub grade, spillage, etc. Specify where and when the concrete is to be delivered. It is best to place your concrete order at least one day in advance.
* PLACING *
You must be ready for placing and finishing when the ready mix truck arrives. You will need the help of at least 4 people for larger jobs (10 yards or more). One of these people should be an experienced concrete finisher. You will most likely need only 2 or 3 people for smaller jobs. The concrete must be placed in the forms and struck off level within 45 minutes after the truck arrives at the jobsite. In hot weather, the work should be done in a shorter time. Moisten the ground and the forms just before placing the concrete. There should be no free water or muddy or soft spots on the sub grade when concrete is placed. Avoid having the heavy trucks back over any existing sidewalks or driveways to deliver the concrete.
Placing concrete is strenuous work and it pays to have several strong people on hand for the job. Place the concrete in the forms to full depth. Strike off concrete with a stiff and straight board (usually a 2x4) that rides on the top of the edge of the forms. Go over the concrete with the strike off board to remove the majority of the high spots in the concrete. If the concrete is below the bottom of the strike off board fill before the second pass. Repeat this striking off process until the concrete is level with the top of the form boards. This will make finishing the concrete a lot easier. Check out the picture of this driveway or this sidewalk for examples of what this looks like.
AVOID PROLONGED CONTACT BETWEEN UNHARDENED CEMENT AND SKIN SURFACES. To prevent such contact, it is advisable to wear protective clothing. Skin areas that have been exposed to wet cement or concrete, either directly or through saturated clothing, should be thoroughly washed with water.
* FINISHING *
Immediately after striking off, work a bull float back and forth across the slab to smooth it and remove irregularities. When water comes to the surface of the concrete, all finishing should stop. Water naturally comes to the surface of the concrete to evaporate when it starts to harden. Any finishing will mix the water back into the surface and create a less durable surface. The concrete will have a glossy appearance at this point. The finishing operations of edging, jointing, floating, troweling, and brooming must wait until all bleed water has left the surface and the concrete stiffens slightly. When the bleed water is gone and the concrete will sustain foot pressure with only slight indentation finishing should begin. Premature floating and troweling of outdoor flatwork particularly may cause scaling, crazing, or dusting, and result in a surface with less wear resistance. DO NOT overwork the concrete; overworking will result in a less durable surface.
* CURING *
Concrete must be cured carefully and deliberately to make it strong and durable. Proper curing is accomplished by keeping the concrete continuously wet for at least 5 days. This can be done in a number of ways. As soon as the concrete is hard, moisten it and cover it. The slab can also be kept continuously wet with a sprinkler.
* WARNING TO THE OWNER *
The owner should be warned about applying deicers too soon. Two of the most common troubles experienced with outdoor concrete flatwork are spalling from freezing and thawing or scaling from application of deicer salts. Although such difficulties should be virtually eliminated by proper concreting and curing procedures , there is some danger of surface scaling if the owner applies deicing salts.
Some of above tips courtesy of Portland Cement Association