Do you have a newly placed driveway, sidewalk or patio?
You’ve decided to place a new concrete patio, driveway or sidewalk. Or perhaps, you are replacing an existing area.
The following tips will help you choose a qualified contractor:
- Ask if the contractor belongs to a builders association or a concrete trade association
- Ask if the contractor has a Flatwork Finisher’s Certification from the American Concrete Institute
- Ask for proof of insurance
- Ask for references. Speak with others who have used the contractor you are considering. Always be wary of contractors who will not give references
- Ask to see examples of the contractor’s work
- Always insist on written contracts. Any changes to the original contract should also be in writing
- Contracts should include warranties and guarantees on the contractor’s work
- Be specific about start and finish dates. However, keep in mind that some delays, such as weather, are beyond the contractor’s control. Allow 2 to 3 days for possible delays
- When looking for a contractor, call your local builders association for recommendations, or visit paconcrete.com
Proper maintenance makes a difference in the life of your concrete. When properly placed, cured, sealed and following the recommendations in this brochure, concrete can last 30 years or longer.
Curing:
Proper curing is essential for durability. Your contractor should begin the curing process, most likely by applying a curing compound following completion of the concrete placement. You can sustain the curing process by maintaining the moist condition of newly placed concrete by moist curing. The optimum time for moist curing is seven days after placement. The longer the concrete is cured, the better.
There are several methods for moist curing, but the most common are continuous spraying/ fogging or a wet covering. Spraying/fogging can be achieved with an ordinary lawn sprinkler, if good coverage is provided and water fun-off is not a concern. Soil-soaker hoses also provide excellent curing. If you choose a moisture-retaining fabric, burlap or cotton mats are recommended. They should be placed on the concrete as soon as it has sufficiently hardened in order to prevent surface damage. The coverings should be kept continuously moist and a film of water should remain on the concrete surface throughout the curing period.
Following curing, a period of at least one month of air drying should elapse to enhance the concrete’s resistance to scaling. After this drying period, a penetrating sealer can be applied for greater durability and resistance to de-icers.
Sealing:
Sealing your concrete will protect it and assure it’s optimum life. For outdoor applications, film-forming sealers containing solvent-based acrylics are the best choice as these sealers allow easy escape of the moisture. A penetrating sealer should be applied at least 30 days after placement and must be placed BEFORE the first frost. Make sure your sealer is capable of forming an impenetrable barrier to protect the concrete surface from corrosive materials such as salts and acids and environmentally safe. Be sure to apply the sealer as directed by the manufacturer. Most sealers will wear with time and reapplication may be necessary. Always consult your contractor before applying sealers.
Wintertime Care:
Concrete that is subjected to use of deicing salts combined with freeze-thaw conditions are prone to scaling.
Please see the PCPC brochure titled “Concrete Scaling” for more information on the harmful effects of deicers.
Refrain from using de-icing chemicals during the first winter following placement. Salt should also be avoided. Sand or sawdust will provide adequate skid reduction in place of harsh materials.
Under no circumstances should a deicer be used on concrete that has not fully cured. While deicers are efficient in melting snow, they can play havoc with freshly placed concrete. We generally recommend that deicers not be used in the first year of the pavement’s life, but even “safe” deicers can cause scaling in the 2nd, 3rd or even 4th year. Typical deicer chemicals are as follows:
- Sodium chloride (Table Salt)
- Calcium Chloride
- Magnesium Chloride
- Potassium Chloride
- Calcium Magnesium Acetate
- Urea, Ammonium Sulfate, Nitrogen Salts
While there are many types of deicers on the market, they all work on lowering the freezing temperature of water. There is a common misconception that concrete is relatively inert. Concrete, in fact, continues to cure and change properties as it matures. The use of these types of chemicals can significantly affect the concrete durability. If you have any doubt of their destructive nature, place a small amount of calcium chloride on a tin pan and observe what effect it has on the tin pan. Deicers tend to amplify freeze-thaw deterioration which can lead to surface defects and possible structural failure.
