How to build a safe, backyard play set for your kids

There are three things you need to consider as you plan any outdoor play structure: which materials to use; design safety; and construction techniques.

In the Toronto suburb where I grew up in the early 1970s, almost none of my friends had their own backyard play set. The only exception was one family with a small tubular metal swing-and-slide combo, the kind that teetered up on two legs whenever a couple of kids swung too hard in the same direction. But since it was the only game around, the lightweight contraption was always crawling with too many kids. I solved this problem for myself by forging a barter arrangement with the girl of the family. I let her hold my cat and she gave me exclusive use of either the swing, the slide or the two-person glider, whichever I chose. It was a good arrangement too, until the cat got tired of being held and ran off, breaking trade relations in the process. It got to the point where I included a supply of cat treats with the cat to extend the life of each deal. But even that didn't help when other kids started scaring my cat away on purpose, a primitive example of economic sabotage.

I'm not sure why homebuilt play sets weren't popular back when I was a kid, but it's a good thing they are now. Today there's plenty of great hardware, tools and ideas to make terrific backyard fun-structures. But even still, you've probably got some questions about how to build right. This is where you'll find answers.

Getting Started

There are three things you need to consider as you plan any outdoor play structure: which materials to use; design safety; and construction techniques. And thanks to recent news coverage about pressure-treated lumber, material choice is more of an issue now than it used to be. For years, the wood of choice for outdoor play sets was pressure-treated lumber. It's cheaper than any other rot-resistant choice, long-lasting and was considered safe based on more than 60 years experience. The active ingredient in the preservative compound is a chemical called chromated copper arsenate, or CCA for short. But concerns over the arsenic component of this substance has raised fears. The word arsenic generally has that effect on people. For the record, no government health authority offers any recommendations against using CCA pressure-treated lumber for kids play structures. And while it's true that this chemical is being voluntarily phased out by industry, there's more involved in this move than you might think.

Alternatives to pressure-treated wood include cedar and some of the new deck wood alternatives. You could also use conventional, untreated construction lumber in areas not in contact with soil if you're satisfied with about a 10-year working life. There's also a case to be made for mixing materials, using the least worrisome products in the highest contact zones like floors and walls. Just remember than none of the new composite wood substitutes are strong enough for structural framing. For that you still need real wood.

Design and Safety

Before you cut any wood, go to a big hardware store and look at the selection of slides, swings, nets, trapezes and handles. You need to buy these plastic and metal parts first, then design around them. A visit like this also shows you ideas on how things are built commercially, so bring a tape measure and note pad, then examine the ready-made structures on display. Besides offering examples of a field-tested design, commercial units are filtered through a surprisingly tough safety watchdog. It's a 110-page document governing hundreds of elements of design, construction and installation. And though this level of detail goes beyond the ability of the average do-it-yourselfer to understand, there are some design features worth considering for backyard play structures.

• The top of railings must be at least 29 inches high for structures used by kids 1 1/2 to 5 years old, and 38 inches tall in areas for kids 5 to 12.
• The area under a play structure is made considerably safer if its covered in sand or other soft-impact, non-compactible material.
• Protective barriers are required on elevated platforms higher than 30 inches for kids 1 1/2 to 5 years old, and around platforms 48 inches and higher for kids 5 to 12.
• Openings within or under protective barriers must be small enough to prevent the passage of a 5 1/4 inch diameter cylinder.

Building Boom

The process of building a kids play structure involves basic carpentry. That's good news because it means almost everyone can get in on the fun. To set you straight on the main construction issues, here are the main things to understand:

• Set support posts in concrete-filled holes that are 42 to 48-inches deep. There's lots of side-to-side forces generated by a maxed-out, fully oscillating swing set. Earth-packed support posts might work loose, especially when the surrounding soil is wet during spring and fall.
• Install vertical support posts longer than needed, then trim them all level at the top afterwards. It's the easiest way to get the posts perfectly level.
• Sand all wood surfaces with an 80-grit abrasive on a belt sander and rout all edges round. These simple steps boost safety and appearance a lot. Always wear a mask when working pressure-treated lumber.
• You'll need a hand-held circular saw or chop saw for cutting main parts, a drill with spade bits for boring bolt holes, some wrenches for tightening nuts bolts, a level to keep things pointing straight up and down, and a hammer, pencil and carpenters square.
• Use only hot-dipped galvanized or stainless steel bolts, screws and nails. Anything else causes ugly rust stains on the wood.
• Install lots of diagonal bracing. Even with concrete-anchored posts, you can't beat the durability of a braced and rigid structure.
• Don't finish your outdoor play structure. The effort-versus-reward payoff doesn't work out well on painting or staining such things. In the long run your project will look better silvery gray than mottled, peeling-paint brown. Take the time you save to play with your kids.

With the supply of backyard play structures higher than when I was a kid, there's more room for little people to have fun and less need for cats to feel nervous when strangers offer tasty treats at odd times of the day. Those are laudable social advances, though there's one more that I like even better. When the kids are wound-up tight indoors, complaining about the boredom of their lives, the words "hey kids, let's have a swing session" is as much a relief to me as them. It works every time.

Is Pressure Treated Wood Kid-Safe?

This question isn't as easy to answer as you might think. There are two reasons why. On one hand the lumber industry has voluntarily moved to halt consumer sales of all lumber treated with chromated copper arsenate (CCA) by Dec. 31, 2003. And this move has been backed up in the US by legislation that outlaws CCA consumer sales by January 2004. That sounds serious, the kind of thing you'd do to deal with a dangerous health risk. But when you look further the issue becomes less clear. Although CCA is being dropped like a hot potato, the official position of regulatory agencies remains the same as it's always been. This material poses no unreasonable health risks. And don't forget, these are the words of independent health watchdogs that don't stand to benefit regardless of what's used to preserve wood. In fact, we're specifically advised by authorities to keep using CCA while available, to leave existing CCA structures standing, and to leave surrounding soil in place.

To answer this apparent contradiction I spoke with Richard Martin, a toxicologist with Health Canada. He explained that the voluntary industry actions halting the sale of CCA have at least as much to do with public perception as solid science. "Ultimately risk equals outrage in the mind of the public", explains Martin. "And we don't want panic because there's nothing to panic about. When people are presented with opportunities to do their own safety homework, they come to decisions they feel comfortable with."

So, is CCA lumber safe when used properly? Would Martin use CCA wood to build a play set for his own children? "Yes, I have used CCA lumber for building and will continue to do so while it's available. During our ongoing re-evaluations of this product we have never found any evidence of problems associated with CCA wood when its handled correctly. But if you still have concerns about an existing structure, there is some evidence that application of a penetrating oil stain reduces the leaching potential of the CCA compound. The last thing we want is for people to over-react and tear down CCA structures. It's unnecessary and potentially more hazardous than leaving them alone."

The best source of information about safe handling of CCA wood I've found comes from a collaborative website put together by Environment Canada, Health Canada and industry players. Check it out for yourself at www.ccasafetyinfo.ca or call Health Canada directly at 800-267-6315.