How to wash and seal / maintain concrete driveways in freeze thaw climate....

Wash and Sealing of Concrete – By Rockscapes Concrete Service

This is a guideline for the restoration and maintenance of concrete. In Saskatoon’s freeze thaw climate, it is particularly important to do proper annual maintenance in order to minimize damage and prolong the life of your concrete. These are some of the techniques that have produced successful results for Rockscapes; we have performed thousands of concrete driveways and / or concrete projects in Saskatoon and area. Other contractors may have different techniques.

Once applied some sealers are virtually impossible to remove.

1)     One of the most useful tips I can offer in our freeze thaw climate is to try to keep your concrete clean (shoveled) and dry during the winter season to keep salty, slushy snow to a minimum, never push salty vehicle salt water from garage and out the door onto your driveway. Especially important with north facing shaded driveways.

2)     Be careful of some of the products out there that say they won’t damage concrete and will melt ice. Sometimes just sprinkling a little clean sand will give that temporary short-term protection required.

3)     Don’t use ice chippers, they will mark or chip your concrete.

WASH THE CONCRETE WITH A PRESSURE WASHER TO RID IT OF MOLD, DIRT, SALT, CRACKS FILLED WITH DIRT ETC. THIS WASH SHOULD BE PERFORMED THE DAY BEFORE YOU INTEND TO SEAL. THE CONCRETE MUST BE COMPLETELY DRY BEFORE APPLYING THE SEALER.  SOME SEALERS WILL WHITEN OR TURN MILKY WITH MOISTURE. (Rope off the area after pressure washing to keep ALL traffic off. The concrete must remain clean of debris for sealing. Otherwise you may trap dirt or debris under the sealer)

·            Exposed Aggregate is prone to rust spots which can be removed to a certain degree

·            Plain broom finish concrete is subject to more pop-outs especially in recent years.

·            Stamped concrete is subject to a colour loss. (Surface release agent colours can peel off with loss of sealer due to salt damage)

All Concrete Driveways, regardless of which style you have, may end up with a few pop-outs, the longer those are left unwashed and unsealed, they will turn into shaled area's over a few years.

Different contractors use different methods of applying sealers including the number of coats applied. At Rockscapes Concrete Service we use 3 coats of concentrated sealer diluted about 30-40% with Xylene. This slows down the curing process and allows the sealer to penetrate the concrete pores and adhere better. Our suppliers sell a version of our sealer that is “ready to use”, pre-diluted and easy to work with.

POPOUTS – Source of Information on this can be obtained at concretesask.org Tech – Tips Pop outs are caused by lightweight aggregates absorbing moisture and then freezing, expanding and

cracking or popping out of the surface. Fixes are difficult; we recommend keeping your driveway shoveled and dry, annual sealing with acrylic sealers to provide topical protection. Mild winters with less snowfalls, moisture mean less popouts and sealing required. Patches can be done, but may be noticeable. Our suppliers do sell products that can be used to patch concrete pop outs.

RUST MARKS - Very difficult work, we use an angle grinder with a wire wheel; we scrub with a 10% solution of Muriatic acid and rinse this off with clean water. It is important to wear safety gear during this job. (Protect your eyes and skin) Some contractors drill out the rust spots and then clean the rust stains in a similar method.

SEALING CONCRETE

If the concrete is dusting or shaling in any areas I recommend using a densifier sealer in those areas first. At Rockscapes Concrete Service we have used a product from Cornerstone Coatings and believe that it has made a significant difference. This is a water-based product and drying time will be required. After this step an acrylic sealer is applied. (Again Acrylic’s are topical sealers, and create a protective film on the surface.)

I believe in topical sealers (Acrylic) to protect and seal out salt and other destructive chemicals. These can be sprayed using quality sprayers like a Chapin. Again, proper drying time is required before allowing any traffic on the concrete. A guideline is 24 hours for driveways. Walkways and patios can be used once dry to the touch. Outside temperature will be a factor in drying time. During sealing with Acrylic sealers, grit can be sprinkled sparsely to provide traction. On a reseal, we recommend two coats of Acrylic. Most home-owners roll on the sealer with a 15 mil roller, paint tray, and handle. It is very hard to clean Acrylic sealer off your roller, At Rockscapes we dispose of used trays and roller cage handles

Source for buying your products,

Prairie Concrete - 30-3703 Kochar Ave – Saskatoon – 306-343-0770 (Kevin Mapes at Prairie Concrete is a very knowledgeable Concrete Expert )

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Article by John Groves, President Rockscapes Concrete Service. More information can found on Rockscapes at:

www.rockscapes.org

rockscapesconcrete.blogspot.ca

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Densifier for Garage floors.... As an option?

WHY CONCRETE DENSIFIERS ARE THE NEW GARAGE FLOOR SEALER

updated 16 April, 2015 by Shea 37 Comments

Concrete densifier with sealer on a garage floor

A new trend that is slowly working its way into the garage is the use of a concrete densifier sealer on the garage floor.  Densifiers have been used on occasion in the garage for a variety of reasons, but rarely as an actual finished garage flooring treatment.  So why has there been a gradual increase in its use and popularity for the garage floor?

The reason is the addition of silicone and siliconate agents in some densifiers to act as a sealer.  This helps to create not only a water repellant floor, but one that is resistant to liquids in general.  So let’s take a closer look at how a concrete densifier with sealer on your garage floor may be beneficial for you.

HOW A CONCRETE DENSIFIER WORKS ON A GARAGE FLOOR

Concrete densifiers have been around for decades.  They are a concrete hardener and in the flooring industry used primarily for concrete floor polishing, abrasion resistance, anti-dusting, and in some cases to harden softer concrete surfaces before grinding.

Lithium densifiers are the most common choice used for garage floors. This is due to their ease of application and less reactive properties to carbon dioxide which can create a whitening effect on the floor. Unlike sodium densifiers, lithium densifiers also do a good job at repelling road salts. Once applied, the concrete retains its natural matte look.

When concrete cures, bleed water makes its way to the surface increasing the water to cement ratio, laitance content, and fine aggregates.  This is what helps to make the surface of concrete smooth, but it also creates a surface that is softer than the underlying cement.  When a densifier is introduced, the chemical reaction increases the surface strength of concrete from an average of 20% to 40% depending on the original pour and finish of the concrete.

It does this in two ways.  The densifier is a water based chemical solution that first works by penetrating into the surface of the concrete and reacting with calcium hydroxide to produce calcium silicate hydrate (CSH).  This is the substance that gives concrete its strength.  Next, the CSH that is produced fills the open pores of the concrete increasing its density.

It’s important to note that concrete densifiers are non-film forming, meaning that they don’t leave a topical film on the surface to protect it from liquids and staining.  This is why they haven’t been used much as a finished product for garage floors – until recently.

The addition of silicone and siliconate agents in densifiers creates a waterproofing agent right at the surface of the concrete.  This allows the concrete densifier to act as a sealer for your garage floor by repelling water, oils, chemicals such as road salts, and other fluids.  They can also be used over stained concrete.

Are they 100% impervious to stains and chemicals?  No, but if you don’t allow spills to sit for a long period, they will generally wipe right up with little if any scrubbing necessary.  Be particularly careful with solvents that can stain, as their resistance to them is minimal.