Friday, September 23, 2011

Installing Concrete Sidewalks at Your New Home

Concrete sidewalks can vary in shapes, colors and be formed into any shape you can imagine. Before starting on this project, look around at other homes and businesses to see what can be done but don't be limited by what you see. Use your imagination. Colored concrete is available today from most Redi-mix suppliers and concrete color stains are also another way to obtain a beautiful finished product. There are "cast-on" products out there that can provide a non-slip surface, a super hard surface and even anti-spalling compounds that help keep the sidewalk from chipping due to the use of winter salt. Most redi-mix concrete dries in some shade of beige color depending on the color if the sand and Portland cement used. Ask your supplier where he has poured his product and go look at it. This will give you an idea of what the "aged" product will look like later. Once you have decided what color concrete you are going to use, decide what strength concrete you need. I recommend the use of 3000# strength concrete for all sidewalks except very heavy use or vehicle traffic. If vehicles will be crossing the sidewalk, use 4000# or 5000#. It will cost a few dollars more a yard, but will last a great deal longer.

masonite hardboard

TOOLS REQUIRED-

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Hammer, sledge, string line, and level with tripod. 4' hand level, pointed and flat shovels, wood 2x4 for screeding (leveling) of the concrete, bolt cutters, safety glasses, work gloves, fine broom and two edger's called sidewalk edger's and v-groove styles. A metal sidewalk edge finishing tool, a V-groove tool for center joints and a steel trowel are a must. Most masons prefer to use a magnesium float to put the initial finish on their walks prior to applying the final broom finish.

MATERIALS REQUIRED-

Concrete is ordered by the cubic yard. It is quite simple to figure out how many yards you need for your project using the following formula: Length x Width x Height (thickness) divided by 27 =? Cubic yards. A typical example: Your sidewalk is 3' wide, 3-0 feet long by 4" thick. Using the formula above: 3' x 30'x.33 /27=1.1 cubic yards. You cannot order.1 cubic yards. So it is either 1 or 1.5 yards. All Redi-mix companies charge what they call a short load charge for anything under 6 yards. So there are choices here to be made. Is there anything else that needs concrete? Make the walk a little wider? Add a patio area? Ask the Redi-mix company what the charge is for 1.5 or 2 yards. The price may be the same anyway. While we here, I want to spend a minute discussing getting the concrete to your site. Trucks are heavy. Very heavy. If your sidewalk or patio is in the rear yard, either the truck has to be able to get to it or you will have to wheel it in wheelbarrows. Wheeling 1 yard is not bad, wheeling 5 or 6 yards is a brute. You will need plenty of help and good wheelbarrows. Redi-mix companies also charge extra for any time spent over 1 hour on site. IF you decide to take the truck into the rear yard, be prepared for lawn damage. Concrete companies are not responsible for damage to your property if you direct them to drive over the lawn. Worse yet is if they pass over the septic system, buried pipes, etc. and damage them. BE SURE there is nothing underneath that can de damaged. Don't guess!

A Redi-Mix truck can weigh over 40,000 pounds! It will leave a lasting impression on your lawn and can damage lightweight asphalt driveways. Be careful where you send it.

You will need some misc. mixed lumber to form your concrete walk. 2x4's in long lengths work best. If you have a curve in the walk, it is best formed using strips of non-tempered masonite or 1/4" plywood. Whatever you use, it does not have to be pretty. It is going to be removed after the pour. Buy a bundle of 1"x2" or 1"x3" for stakes. These can be cut into 1 foot lengths and points cut on them. You will also need a couple of pounds of 8 penny common nails.

LAYOUT-

The easiest way to layout a new sidewalk is to use your garden hose. Simply lay the hose out on the ground where you want the walk to go. Forms do not have to be made of wood. Things such as brick, wood edging, pre-formed plastic edging are all used and produce many different edge finishes. If you use these types of things, just take extra care not to splash concrete on them. Concrete stains or discolors very easily and does not wash off well. When everything dries, the concrete you think you washed off, leaves a permanent stain. Another very helpful item available today for homeowner use is upside down paint at most hardware or box stores and comes in a variety of colors. This makes it very easy to spray a layout line for digging or removing sod or soil. DO NOT spray your hose unless you want it to be that color for a very long time. A few carefully placed spots that you connect after removing the hose is fine.

Make sure that you mark out the lines a few inches wider than the finished walk width. You need to get your 2 x4's and stakes inside the excavation and in most cases flush with the surrounding ground. If you are going to expose the edges of the new walk above ground, you will also have to finish the edges when you pour.

GROUND PREPARATION-

Never, never place concrete on frozen ground or mud. You need a firm foundation base for the new walk. You must remove the concrete thickness of earth plus the stone you will be placing underneath. A 4" walk usually gets 4" of stone base or good clean run-of bank sand and gravel. After removing the 8" of earth, place your sub-base material and tamp into place. Make it slightly wider than you walk width. Your forms will sit on top of the base. NOTE: Now is the time to run any yard lighting wires or conduits under the walk before you pour. Even if the lighting is in the future, you will be glad you make preparations now. Place a piece of 1" PVC conduit with caps under the walk for future use.

FORM WORK-

OK, we are using wood forms for this walk. Layout your 2x4's along the walk and drop stakes every few feet. Your 2x4s will be installed end to end so a stake is required at each joint. Starting on one side, install your 2x4's using enough stakes to firmly hold them in place. They must be straight and plumb. Nail the 2x4"s to each stake but DO NOT drive the heads all the way in. You have to remove these stakes later and it is a lot easier to get a hold of the nail head if it sticking out a little. If you have curves in your walk and are using 1/4" material to form you will of course have to use many more stakes. Just make sure the form is not going to move when you place the concrete against it.

Now cut a piece of scrap 1x2 the width of your walk. (3' in this case). Using this as a guide, install the opposite side of your formwork. It will save you having to measure over and over again and speeds up the work.

CONCRETE PLACING-

Ok, now we are ready to go. Check your list. Forms are all nailed? Not raining? Plenty of help? Got all the tools you need?

And most important did you order the concrete? Most companies require at least two days notice for homeowners to order. Commercial accounts come first due to their large volume of orders. BE READY! Remember the truck clock starts when he gets there, not when you start pouring. Using your garden hose, if the ground is very dry, slightly dampen it. This will help prevent premature drying of the concrete by the ground sucking the water out of the concrete before you get finished. Starting at the end the farthest from the truck (you will see why later) start placing the concrete in the forms. One person must, using his trowel, push the concrete into place and do a preliminary leveling within the forms. After placing a few feet of concrete, using a 2x4 as a screed, he can then level the entire width of the walk by sliding the 2x4 back forth over the top of the forms. You need one person leveling concrete with shovel, 2nd person using 2x4 as a screed to level concrete flush with the tops of forms and an extra third hand to wheel concrete, handle the chute, etc.

If a low spot in the concrete develops, just use the trowel to pickup some wet concrete and toss it in. Move back and re-screed over that area. If too much concrete develops in front of the screed just push or pull it into the area without concrete. You will soon get the hang of it. The people helping can watch as they pour the concrete from their wheelbarrows to be sure they don't overwhelm you. If you work slow and steady it goes pretty fast. OK, we now have the entire form filled with concrete. Place a little bit extra in one wheelbarrow and let the truck go. Now you need somewhere for the truck to wash out his chutes and you need to wash your tools and wheelbarrows. Concrete stains and gets HARD! Put it somewhere that can be easily cleaned later. Do not leave piles of concrete that cannot be moved.

FINISHING-

You get a few minutes break here. Have your favorite beverage and relax a little. The concrete will take a little while to start to setup but keep an eye on it. Touch it with your finger just like a cake. If it feels somewhat solid, now is the time to put the preliminary edge on it. Using the edger with a rolled lip, run it along the entire outside edges of your walk way. This will form a smooth sealed edge. You will have to pickup the edger many times and re-start. Just backup a few inches and moving ahead to remove the lip left when you picked the edger up. This will take some time so don't let the concrete "get away" (harden) on you. Once you have done an area, a 2nd person can start placing the v-grooves every 4 or 5 feet (less if you like the look). Using the edger, simply push the edger across the width of the walkway with enough pressure that both sides of the edger sit firmly on the concrete. This will leave a neat v-groove in the walk. You will get the hang of this very quickly. Don't worry for now about the little lip of concrete left on each side of the new groove and edges you made. Now using your broom, very lightly draw it across the width of the walk way being careful not to draw it across the v-grooves but do some very close to them and the edge of the walk. Read that sentence again. You can ruin the whole appearance of the walk if you mess this up. Be gentle but firm enough to leave broom lines in the concrete and wipe away the little lips of concrete you left behind when edging. The broom lines can be as heavy or as light as you like. This will leave a non-slip surface. Always broom across the path of the traffic, never with it. The trick here is to not to let the concrete harden before you are done. Start with a SMALL project and work your way up. After your first pour, you will know some of the tricks and better able to judge how fast concrete sets up.

Keep some plastic or tarps handy just in case you get a surprise downpour. You can quickly throw plastic over the pour and save it. If the rain washes out the top layer of concrete, the walk will be ruined.

It is very strongly suggested that you do not leave a smooth or hard trowel finish on any outside walk. It will become very slippery when wet. A broom finished side walk is what you normally see. There are colored aggregates that can be scattered over a walk to add color and a non-slip surface at the same time.

OTHER FINISHES-

Stamping-There are available metal stamping tools that can be used to place an imprint in wet concrete to simulate stone, pavers, brick, etc. These can produce a dramatic effect from plain concrete but take some experience to use.

COLORING-
You may be able to buy pre-colored concrete from your supplier. It is expensive but can come in many different colors. It is produced from regular wet concrete with a powder added to the mix while still in the truck. Pour the entire area in one pour. Just a slight change in the amount of powder or water or sand in each truck can produce a different shade of concrete. This will show when dry. The powder is measured in ounces with a postal scale. It is that exacting. Concrete suppliers have color charts for concrete but this needs to be ordered well ahead of time as they do not stock all colors.

EXPOSED AGGREGATE-

This is a really tricky method of finishing concrete. You purchase your concrete specifying the use of round washed river rock 3/4" or smaller. If you visit the concrete supplier, you can see what color the gravel he has available. Most river rock is beige/brown in various shades. It is not an exact science though and there will be some variation from week to week of what you can get. I have on occasion for a very large project, ordered enough stone to supply the total amount of yards required for the work. The supplier will of course want payment as he will have to wait to supply it as you need it, but it is one way to control final color and costs. Placement of the concrete is the same as any other side walk however the finishing is much different. After edging your walk, using your trowel you must place a flat finish on the walkway and let it sit. At just the right time, using your garden hose and spray nozzle, you literally wash off the top of the concrete removing the cement and leaving the stones beneath exposed. It is tricky but leaves a gorgeous finish. Too much water or pressure and you undermine the stones, too little and the concrete won't wash off enough to leave the stones exposed. The trick here is wash to before it gets too hard. You might well want to try process on a small test sample during a different pour. Washing lets the color of the stones show through. Do not try to finish after washing; you will smear the final finish

CLEANUP-

Always clean up your tools and yourself as soon as possible after the pour. Concrete can cause serious burns to the skin due to the lye in the concrete and many people are quite allergic to it. Always wear eye protection when pouring concrete. No matter how careful you are placing the concrete, it splashes everywhere. A small drop in your eye can cause serious pain and permanent eye injury. Place covers on anything you do not want concrete to get upon. Shrubs, flowers, lawns, etc. should be protected.

Enjoy your new sidewalk. You saved a ton of money doing it yourself.

Installing Concrete Sidewalks at Your New Home

Pete
Your Friendly Building Inspector

http://www.Wagsys.com

BICES-Building Inspection & Code Enforcement System Software

Pete is a 30+ year building inspector with experience in both public and private construction industries. From schools to treatment plants, from private homes and condo projects, to large residential landscaping projects, he has worked both in the building design areas and field construction in the Eastern US. In 2006 he formed along with two other building inspectors, Wagsys LLC which produced software for municipal agencies in the fields of building departments, planning boards and Zoning Boards of Appeals.

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