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Efflorescence: What Is It?


Efflorescence is a deposit of white chalky crystals that can sometimes appear on the surface of concrete products and other porous building materials, which have soluble salts in them.

The primary cause is moisture; moisture must be present to pick up the soluble salts and transfer them to the surface of the concrete, the water evaporates, leaving behind an unsightly white chalky powder. Natural occurring salts are found in soil, water, gravel and cement are dissolved by rain and ground water.

To minimize the appearance of efflorescence, make sure the pavers are kept dry, so providing a properly draining base for the pavers to sit on is very important.

The efflorescence will wear off over time, but if you are in a hurry, using a stiff bristle broom and water may be a quick fix, however if the process has not stopped then the efflorescence will reappear and need to be cleaned again.

In stubborn cases of efflorescence, it can be removed using an efflorescence cleaner, make sure it has been specially formulated to be used on concrete or natural stone, making sure you follow the directions as listed on the container. Be sure to test in an inconspicuous area before cleaning the entire area.

How to Pick a Contractor

How to pick a contractor?

Suggested Questions to Ask Contractors

ICPI recommends getting written proposals from at least three contractors. Be sure the contractor visits your home before providing the proposal. Please note that the lowest bid might not always be the best option. To ensure a quality installation, be sure to ask the following questions:

  • How long have they been installing pavers?
  • Have they been trained by a manufacturer or the ICPI? Are they ICPI Certified Installers? 
  • What percentage of their total business consists of installing concrete pavers?
  • Will they provide you with three references? Be sure to ask for references from recent and past jobs. Can you contact their references and inspect the jobs?
  • Do they have a portfolio of photos and letters to qualify themselves?

While the contractor is working on your property, they should be insured for any damage and injuries that may occur. Check your homeowner's insurance policy for coverage of the contractor while on your property.

  • Can the contractor provide proof that Worker's Compensation insurance covers all employees on the job?
  • Do they have current Liability Insurance? Ask for a copy of the certificate.
  • Will they install the job per ICPI specifications? Can they supply a copy? 
  • Do they provide a written, itemized proposal outlining the scope of work and terms of payment? It should include starting and completion dates, demolition and excavation, paving and base materials, and taxes.
  • Do they guarantee their work for one year and will they return to inspect it?
  • Are they members of the ICPI or other associations?

Gator Base

One Gator Base panel is equivalent to 6˝ of crushed stone. The inter-locking panels distribute all dynamic loads to a very wide area practically eliminating any pressure on the ground.

Gator base way

For more information and installation instructions, visit the Gator Base product website:

Paver installation icpi logo

Step 1: Planning

Start by sketching out a diagram of the area to be paved.
Record all of the dimensions and note any existing structures such as your home, stairs, or other paved areas.

Visit your local concrete paver manufacturer or dealer to view product samples. Show them your sketch and discuss the various shapes and pattern options available. Keep in mind that some shapes and laying patterns require less cutting.

Determine the amount of pavers, edge restraints, bedding sand, base material, geotextile and other materials you’ll need for the project. Your concrete paver manufacturer or dealer should be able to help you calculate this. Be sure to consider any waste you’ll have in materials due to cuts.

Plan out your site and the flow of materials to determine where you place them when they are delivered. The materials are heavy so you’ll want to have them delivered to a safe and convenient location close to the job site.

You will need the following tools and equipment:

  • Gloves
  • Safety glasses
  • Carpenter’s chalk line
  • Tape measure
  • Push broom
  • Wood stakes
  • Rubber mallet
  • Shovel
  • Steel rake
  • Wheelbarrow
  • String line
  • Spray paint
  • Level
  • Carpenter’s Square
  • 2 pieces of 1” OD PVC Pipe (screed pipe), 8 feet long
  • 1 piece of 2”x4” kiln dried lumber (screed board), 8 feet long
  • Plate compactor (rent)
  • Stone cutter or masonry saw (rent)

Depending on the details of your project, you may need additional tools and equipment

Step 2: Site Preparation

Contact local utility locating service to mark all underground services. These services are usually free but typically require advance notice. They may not be able to locate in-ground sprinkler systems, so be sure to mark those on your own.

Mark out the area to be paved. You can use a garden hose or spray paint to layout the shape and curves of the area. To form a circle, use a stake at the center point and use string line and spray paint to mark out the desired radius.

To guide the paving lines, it is best to square off a 90° corner. If there is not an existing structure to measure off of, use a "3-4-5 triangle" method. Begin by measuring 3' along a corner and 4' from one side, adjusting them until the distance of the diagonal line is 5’ long. The angle opposite the 5' side will be 90°. A 24” carpenter’s square can also be used. Note: You will need to do this again when setting the edging and laying the pavers.

Make sure to allow an additional 6” on each side of the pavement (except where the pavement abuts a wall, curb, or foundation, etc.) to allow for drainage and edge restraints.

Set stakes along the perimeter and connect them with the string line.

Level the strings around the project using a string line level.

Step 3: Excavation

If you have a large area to excavate, consider hiring a contractor. They can haul away and dispose of the excavated material. For smaller areas, a shovel and some hard work will get the job done.
Remove grass, roots, large rocks, etc.

Use a flat shovel or spade to skim off ½” to leave the subgrade soil undisturbed.

The depth of the excavation depends on the project and the type of soil. The base under the pavers must be thick enough to support weight and avoid rutting over time.

Expand the excavation laterally beyond the perimeter of the finished pavement by the thickness of the base to provide a shoulder on which the edge restraint will be installed.

Determine whether you have granular or clay type soil. Granular soils are best for drainage and strength and clay soil is weaker are requires a thicker aggregate base.

Determine the elevation and slope of your finished pavement. It should be approximately ¼” above the surrounding area to allow for drainage. The pavement must be sloped ¼” per foot to encourage water to run off the pavement. Establish the slope by pulling string lines across the width of the excavated area and leveling them using a line level. On the side you wish to slope towards (make sure it is sloping away from your house), move the string lines down ¼” for every foot that the pavement is wide. For example, foot a 4’ wide walkway, you will need to lower the string 1”.

Tip: Since the string lines will need to be removed in order to compact the subgrade, mark their position on the stakes. You can easily reset the string lines for other steps of the installation.

Increase base thickness by 50% in areas where the ground is subject to freezing temperatures. Increase excavation depth to account for additional base thickness.

Compact the excavated subgrade soil with a plate compactor to create a firm and stable foundation for the base.

Step 4: Install the Base

Base installation is the most important step in a successful pavement installation.

Fill in the excavated area with coarse, angular gravel in layers, compacting and sloping between each layer. Compacting in thinner layers will reduce the potential for long term settlement.

Use the 2x4 and string lines as a guide to assure a perfect base installation.

Proper compaction and a smooth pitched surface base is vital…do not rush this step!

Tip: For every 100 square feet of area, you will need the following amount of base material:

  • 4” thick – 2 tons
  • 6” thick – 3 tons
  • 8” thick – 4 tons
  • 12” thick – 6 tons

Step 5: Install Edge Restraints

Since pavers are set loose in sand, they must be secured in place along the perimeter. A house foundation or curb is suitable but for any edge that does not have this, such as along grass, you will need to install an edge restraint.

Position your edge restraint and nail it into the aggregate base. Be sure that all square corners are exactly 90-degree angles. You can use the 3-4-5 triangle method noted above.

Step 6: Place the Bedding Sand

Before the pavers can be placed, a setting bed of washed concrete sand must be installed and leveled. This process is called screeding.

Add the bedding sand and smooth it out (do not compact) using the PVC pipes as guides or rails and the 2x4 board. The top of the pipes should be 1 ¾” to 2” inches below the finished elevation to allow room for the pavers to be laid on top at your final elevation.

Do approximately 6’- 8' sections at a time and be sure to lay pavers before preparing the next section of sand. Use a trowel to fill in the gaps left behind by the pipes after you remove them.

Do not walk on or disturb the freshly placed sand.

Step 7: Lay the Pavers

Most pavers can be installed in a variety of laying patterns.
Lay the pavers on top of the smooth sand, beginning at the 90-degree angle you established previously.

Place the pavers on the screeded sand bed along a straight line in the pattern you selected.

Install the pavers “hand-tight” so that the joints between the pavers are about 1/8” wide.

Hold the paver so the bottom 1/4" to 1/2" clicks against the top edge of the paver already in the sand. Release your grasp dropping the paver directly downward. Do not slide the paver across the sand.
Every couple of feet, check to ensure pattern lines are straight and spacing is consistent.

Tip: Always select pavers from different layers and from different cubes to ensure even distribution of color.

Tip: For pavements with curves, continue the pattern just beyond the width of the pavement. Mark and cut the pavers along the perimeter to accommodate the curve.

Step 8: Cutting Pavers

Once you have laid all the pavers that will fit your area, you may need to cut some to fit neatly along the edges of the pavement.

Measure and mark the pavers to be cut with a marking crayon. Always cut the paver in the shortest direction for a clean cut. Don’t be concerned if a cut is not perfect as jointing sand will fill the gaps.
Use your stone cutter for simple cross cuts or masonry saw for more precise cuts.

Always use safety glass, gloves, and a dust mask when cutting pavers. Review the cutter/saw manufacturer’s instructions carefully before attempting to use.

Step 9: Compact the Pavers

Using the plate compactor, make two passes over the installed pavers starting at the outside and working toward the center. This will seat the pavers, forcing sand up between the joint and completing the interlocking effect of the pavement system.

Spread additional sand over the surface and sweep into the joints, and compact again.
Repeat process until all joints are filled.

Tip: If your pavers have a textured surface, use a compactor with a urethane pad or place a sheet of geotextile or old low-pile carpet, over the surface before compacting to reduce scuffing.

Congratulations, you are finished! Review our maintenance section for information on proper care and cleaning of your new interlocking concrete pavement.

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Seal King Installation Guide

Seal King Installation Guide


Pressure washer or garden hose, Goggles, Rubber gloves, Stiff brush, Broom, Paint roller or Pump Sprayer.

Step One

INSPECTING. Determine which cleaning products and quantity of protective sealant is needed. This is done by thoroughly inspecting the surface to be treated and measuring the total square footage of the stone, concrete or wood.

Step Two

READ ALL INSTRUCTIONS on product labels and data sheets found on the website. We recommend reviewing the Material Safety Data Sheets found on the website (under each product page) as well.

Step Three

CLEAN all stains, spills and debris from the area you are sealing, using either a scrub brush or pressure washer. Please Note! If stains are not removed, the sealer can magnify these unwanted blemishes. Removing them will be more difficult once sealed.

Step Four

WAIT until surface is completely dry before applying Seal King sealant. Usually 24 hours is sufficient. Also make sure the polymeric sand is completely dry.

Step Five

APPLY Seal King sealant using an industrial pump sprayer or paint roller.

Step Six

BLOCK AREA TREATED. Prevent anyone or anything from contacting the treated area. Usually 4 to 24 hours, depending on the product type. (Refer to product label for suggested wait times.)

Please Note

Seal King recommends using a professional installer. Make sure that when using an installer, they have multiple years of experience or legitimate references.

Topdressing the Lawn

Topdressing the Lawn

What is topdressing?

Topdressing a lawn is the process of adding a thin layer of material over the lawn. Typically 1/4 inch - 1/2 inch of compost or other soil amendment is spread across the lawn with shovels, in a throwing action. The material can be worked into the thatch area by raking, washed in with rain or sprinklers, or allowed to settle on its own.

Why topdress?

Topdressing's benefits are so numerous, it's hard to understand why it is not the foundation for every lawn care program on the planet. As a soil amendment, topdressing can improve soil biology by adding organic matter and the beneficial microorganisms of compost. Soil structure and drainage can be modified by topdressing with sand or other corrective materials. Topdressing regularly can smooth out bumps caused by worm castings and encourages a dense, lush lawn. Topdressing reduces lawn stresses, helps keep thatch under control and acts as a long-term natural fertilizer. Adding organic matter to a lawn by topdressing with compost is the most beneficial cultural practice lawn care has to offer.

How to topdress:

Topdressing can be quite labor intensive and at the very least requires shoveling and moving piles of compost or other topdressing materials. The hard work is worth it though and new machines are now available to save on much of the manual labor. Traditionally, topdressing is spread by the shovelful in a manner that I have always felt was similar to taking a shot with a hockey stick. A smooth, sweeping motion aimed at trying to spread the material as evenly as possible to a depth of 1/4 inch to 1/2 inch. Topdressing machines are also available and consist of a hopper to hold the material with a motorized belt to move the product through the hopper to a spinning disc which spreads it on the lawn. These machines are just beginning to get popular as more and more people request topdressing with compost as part of their lawn care regimen.

When topdressing, it is beneficial to do it in conjunction with other cultural practices like aerating, de-thatching and overseeding. Topdressing after aerating and overseeding is the ideal trio of lawn care chores that will result in a healthier lawn. The aerating opens up the soil, allowing for better air and water movement and reduced compaction. The aeration holes provide the perfect seed bed for overseeding, allowing newer generations of grass to establish and thrive. Lastly, topdressing with compost, helps fill in the holes, covering the seed and allowing for ideal germination conditions with a burst of nutrients as the seedlings establish. It's a win, win, win, situation.


How to Install Surefoot Brick Edge: Videos

Plastic Paver Edge:
Plastic Paver Profile

Aluminum Paver Edge

Laying Sod for a New Lawn

How to Lay Sod for a New Lawn

By Lance Walheim, The National Gardening Association

Laying sod is a gratifying experience—you get a new, green lawn in no time! The time to lay sod is early morning before it gets too hot. The soil in the planting area should be moist, not soggy or dry. Water thoroughly one or two days before the sod is delivered so that the top several inches of soil are wetted. Then allow time for the soil to drain so that it’s not muddy and is workable.

1. Fertilize the soil.
Before you begin laying the sod, apply fertilizer to the entire area after the final leveling. No need to rake the fertilizer into the soil — you lay the sod right on top of it.

2. Make sure the sod is moist.
The sod should be cool and moist to the touch, but not dripping wet. Sprinkle the sod quickly to keep it cool, but don’t soak it. Then, as soon as you’ve laid down the sod, soak it with impunity. You can even start watering before all the sod is laid.

3. Choose the right place for the first row of sod.
Start laying sod along a straight edge, such as next to a walk or driveway, so that everything starts off straight. If your lawn has an irregular shape, run a string across the center of the lawn area, with each end of the string attached to a stake. Lay sod on either side of the string.

4. Unroll the first piece of sod.
To avoid roughing up the planting surface or the new sod, kneel on a board or piece of plywood as you work. Make sure that you place the edges of the sod tightly against any hard surfaces, such as cement edgings, walks, or driveways. Otherwise, you have empty gaps where the edges of the sod can dry out.

5. Set the loose end of the second piece tightly against the end of the first piece and unroll it.
Handle the sod with care so that it doesn’t tear or fall apart as you move it.

6. Cinch the edges as close as possible without overlapping or stretching the sod.
Stagger the ends as if you’re laying brick; The edges of the sod are the first part to dry out.

7. Level the planting surface with a rake as you go.
If part of the planting surface gets roughed up, level it with a steel rake. Otherwise, you’ll have a bumpy lawn. Occasionally, you may need to lift a piece of sod, rake level, and then replace the sod.

8. When you come to the end of a row, roll the sod out over the edge and cut it to fit with a sharp knife.
If you have in-ground sprinklers, cut small holes in the sod to fit it around them.

9. After you lay out all the sod, place soil in any open seams between pieces of sod.
Potting soil is ideal because it’s weedfree, or you can use organic matter such as peat moss. Don’t try to fill the spaces with small pieces of sod, which dry out too fast and are likely to die.

10. Roll the sod with a water-filled roller.
To help level the sod and ensure good contact between roots and soil, you need to roll the sod. Use a roller that’s half full of water. Roll perpendicular to the length of the sod.

11. Water the lawn thoroughly, applying enough to wet the soil 6 to 8 inches deep below the sod.
Probe the soil under the sod with a stiff wire to see how far the water penetrates. If you’re planting a really big lawn or if it’s hot or windy, you may need to use a hose to hand-sprinkle dry areas of the rolled out sod before you finish planting.

Slime Mould on Mulch

Slime Mould on Mulch

Tending your garden, you may have noticed the sudden appearance of slimy mass growing on the top of your mulch. It may have an unpleasant smell and comes in a variety of colours and textures. What you have discovered is Slime Mould. Also known as “Dogs Vomit Mould”, this mould is extremely common on the forest floor, and in healthy gardens rich in organics. It has been observed that this mould tends to like mulched, damp garden beds and become more prevalent during the summer months.

Slime Moulds tend to grow in and around decaying matter. This includes yard waste and decomposing mulches. The mould does not feed on the decaying matter itself; rather it feeds on the bacteria and any other fungal spores present. What is observed in the garden as a slimy or gelatinous mass is the active feeding stage of this moulds life cycle. It will take on various characteristics, sometimes appearing as a mottled mass that looks like dog vomit, other times it will take on bright bold colours like pink and orange. When it begins to appear gray and dry, the mould is beginning to produce its fruiting bodies. At this point it has almost completed its lifecycle.

Regardless of the stage in which you find this mould in, it is considered harmless. There is no evidence to suggest that it will cause harm to children or animals if ingested. In regards to plant material, it will only cause adverse effects if the mass causes any shading of the foliage.

To get rid of this unsightly and at times smelly mass, you have a couple of options. The most effective method is to shovel the mass into a bag and throw it out in your regular household waste. There is also the option of spraying the mass with a strong jet of water to break it up. However, the spores travel best in water and you may end up with multiple patches appearing should conditions be favourable. Otherwise, you can observe and enjoy the interesting and at times beautiful Slime Mould.

Prepared by: Lindsay Barker c/o Gro-Bark
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