I’d like to start out by saying this: *It’s not my fault*.

When you start a blog, you set these mental goals for yourself:

- Try not to suck.
- Have fun.
- Find someone who will read it who did not birth you.
- Always be honest.
- Never talk about the Pythagorean theorem.

Stuff like that. Today that last goal flies out the window. (And maybe the first one too. We’ll see.)

I blame Andy for finding a way to put the Pythagorean theorem in my blog. He’s a math teacher and he’s geeky and I suspect he may have built this whole playset with the end goal of finding a way to talk about math to all the peoples of the internets. I’d like to apologize in advance.

Okay, here’s Andy with the LAST part of our playset tutorial. If you missed the first three parts, you can check them out here, here and here.

Yes.

Yes, I did build this playset just so I could talk about theorems and numbers and star wars. But the end result is a whole playground for only about $440 (max), so I think that’s a win.

When we last left off, we were ready to build a roof on this bad boy. I had no idea how I would do it or what material I’d use, so this is all a result of experimentation.

You can do it a hundred different ways. If you don’t like the material I used, feel free to change it out. Use decking. Use playset roof material. Use woven strands from the ponytail of a majestic unicorn. Totally up to you.

Our son Weston likes to sit up in the tower and throw acorns, nuts and small mammals out the side. Meanwhile, the sun shines down in the treeless opening straight above the playset and torches his poor pale white-boy skin.

*Actual photo.*

So finally a year and a half after building this playground, we added a roof. It took a long time because I couldn’t decide what kind of roof material to use. Options were wood decking, corrugated plastic, asphalt shingles or corrugated metal sheets.

We ended up using this black mesh tarp. It blocks most of the sun, breathes well so air still circulates, resists mildew and is CHEAP.

But before we put it on, we need to build the structure for the roof, including two more 2×4’s connecting the front and back.

Since the roof won’t really be supporting any weight, we kept it very simple. There’s probably a thousand different ways we could have built the roof but this is how we did it. Here’s the plan:

1. Cut the rafter to the correct angle and length using a framing square and a circular saw or a miter saw. (More on this in a second.)

2. Cut the ridge to length. (This is just the distance from the front to the back of the playset.)

3. Cut the collar ties to the correct angle and length. (These make everything a little more solid).

4. Screw it all together.

All the wood used here is pressure treated 2×4’s.

### Step 1: Cutting the rafters

Before you cut the rafters you have to decide how steep you want the roof to be. Hang with me here, because we’re going to get mathy for a second, but I promise it’s not complicated.

We decided to use an 8/12 roof pitch, which means for every 12 inches the roof goes over, it goes up 8 inches.

Since our playset is 72 inches wide, each rafter will go over 36 inches, and since we are using an 8/12 roof pitch, it will go up 24 inches:

If you are really confused right now read this page and see if it makes a little more sense. If not, ask a question in the comments and I’ll try to help you.

I love that I’m about to say this and there’s nothing Kelly can do about it. To find the length of the rafter we use the Pythagorean Theorem!!!! Do you remember it?

### a^{2} + b^{2} = c^{2}

So we do 24^{2} + 35.25^{2} = c^{2 }(I used 35.25 instead of 36 because I have to account for the width of the ridge that will sit between the rafters)

Which is 576 + 1242.6 = c^{2}

Add and we get 1818.6 = c^{2}

To find c, which is the length of the rafter, we do the square root of 1818.6 which is 42.64 inches. We can just use 42 5/8 to keep it simple.

### Yaaaaaay, I got to teach math during the summer!

Now that we know the length of the rafters, we need to cut the angles.

To do this we need to use our framing square and we need to remember that we are making an 8/12 roof pitch. Here’s how to use your framing square.

Now you just have to draw a line to mark where you will make your cut. You only have to do this once because all of the rafters will use the same angle and you can use this one as a guide for the others.

If you are using a miter saw you can just set the angle to match your line and then make the cut on all of your rafters.

If you don’t have a framing square or just want to cheat, you can go back to the page I sent you to earlier and they have all of the angles for each roof pitch. For example an 8/12 roof has an angle of 33.69 degrees. I was going to show you how to find that angle using trigonometry but I don’t want to ruin your day.

Now we cut the rafter to the correct length, which for us is 42 5/8 inches. Our goal is for it to look like this.

Notice that the two ends are parallel (I’m secretly trying to get as many math words in here as possible) so once you set the miter saw angle, just measure and cut. Make four of these exactly the same size.

I decided that I wanted the rafters to sit flat on the 2×4 so I needed to cut the correct angle. It’s easy to do this with a speed square or anything thing that gives you a right angle.

Just draw a line that is perpendicular to the end of the rafter.

Then chop it off. My miter saw doesn’t rotate far enough so I used my circular saw.

This is what it will look like after you’ve done it to all of your rafters. I put the little piece of 2×4 between them to show where the rafters will meet the ridge board. Now we make the cuts for the 2 collar ties. The easiest way is to lay your rafters on the ground like I did and trace where you need make the cut on the collar ties.

Mark your collar tie at each of the 4 arrows, then use a straight edge to draw your cut line, and then make your cuts with a circular saw. You can use the first one as a template to make the second one exactly the same.

Continue using the little scrap 2×4 to keep everything spaced and put some screws into the collar tie to hold everyting together.

Here are our two completed rafters with collar ties holding them together. Now we cut the ridge board to length and mount it all to the playset with screws.

I only put screws on one side of the rafter on both the front and the back so that I could slide in the ridge easier.

After both the front and back rafters were screwed down on one side, I slid the ridge into place, screwed down the other side of the rafter and then screwed the rafters into the ridge. You will probably need help holding everything together while you screw it down. (Read: Kelly, put the camera down and get up here and help me.)

A little note…

It’s taking me at least twice as long to tell you how to do this than it took me to do it myself. It’s really not complicated. Maybe I should have just gone to your house and did it for you. Oops, too late now. You’re on your own.

Finally we are at the last step: stapling on the mesh tarp. We kind of thought of it as an upholstery situation and decided to use our amazing staple gun (available here) – the same one we used to make our upholstered bed. I just folded over the front edge a couple times, got it to look nice, and stapled it down.

Then I pulled it tight and did the same on the back and then the sides. I ended up needing to cut some of it off because there was too much to fold up and it was getting too thick for the staples.

On the sides we folded it up underneath the 2×4 and then stapled it on the bottom.

And that’s all!

Here’s a happy boy enjoying his new shade.

And that’s the complete, exhaustive tutorial for how we built our own playground from scratch. Don’t forget to see Part 1, Part 2 and Part 3.

Whew! So what do you think? Have you ever had more fun than you did reading through the section on Pythagorean Theorem? Do you hope Kelly will find new ways to integrate math education on this blog? (I don’t think you have to worry too much about that.)

*This post contains affiliate links.*

Hey, tell Bob Vila there that I have a friend that’s a girl, and also a high school math teacher in the ATL, that would have figured out a way to add a ‘hey girl’ in there to at least keep our brains from permanently shutting down due to mathological over-stimulation and/or Mr. Pearl flashbacks {don’t ask}.

This is probably all fun and games to him, but now I can’t read another blog without fear somebody is going to expect me to calculate the square root of Archimedes. Way to hit us where we live, Andy. Cute playset, though!

Ha, I tried to warn you. 🙂

you really know how to raise the roof.

AHAHAHA. Ten points to you.

“Yaaaaay I got to teach math during the summer!” <—- seriously made me laugh out loud. My husband would be excited about the same thing. He started doing a "Summer Math Series" on his own blog (rockyroer.blogspot.com) but I was the only one commenting on it… I just might have to show him this post for some inspiration. Thanks for appealing to us math-y types. 🙂

Mr. Andy, can I make my roof out of old math homework?

I remember the PT fondly. After English, math was my best subject, which is weird to me. Maybe next week I will post about dangling modifiers so I can also teach my subject in the summer…

My grandmother was a math teacher and she basically tried to throw it in to general conversation so at least this related to math. Nice job Andy! I definitely like the mesh. I’m sure it feels much more open than if you’d used a more solid material.

Rise over run, baby… see, some of us out here dig Pythagoras… hahaha!

Great solution to a real problem, yo! Our yard is about as big as a gnat, so there are NO playgrounds at our house…

Ugg… Math :p Luckily for you I didn’t run away screaming (it was the mention of unicorns that kept me)

The roof looks great though! 🙂

I’m really bad at math so I only read Kelly’s part. And it was funny. Sorry.

I have a ripped Rainbow play system room that I can see from here. I’m sure a new one is the price of a small island, so I’ll be checking out your idea for mesh.

~Bliss~

Wow, awesome–the play set, the mesh cover, the math–all of it! Hey, maybe this will be the post that lures my math teacher husband over to the wide world of shelter blogs. Thanks, Andy!

The only part of that I understood was the part with the staple gun. THAT I can do. 😉

I LOVE the Pythagorean theorem*. (*not a true statement) But I’m pinning anyway because I’m sure there are other geeks, I mean, smart people out there who do.

I love the idea of the mesh! Looks great!

oh the pythagorean theorum, i thought I was rid of you after geometry in high school! math stuff makes my eyes glaze over. I was invigorated by all the photos of your awesome and adorable playset though, thanks for throwing pics in there to keep us focused! Now that’s what the high school match books should do…

As far as I’m concerned, you can talk about math all you want as long as it’s this entertaining! And a playset for roughly $400?? getouttahere…..

Kelly,

I couldn’t get past the line “sit up in the tower and throw acorns, nuts and small mammals out the side” 🙂

You are so funny! That is an amazing play set and Math rocks!

🙂 karianne

Ha! Got to love a little math in the summertime.

This is fantastic! I’m seriously such a math nerd, so in my opinion, “You’re awesome!”

My eyes are glazing just like they did in my high school math days! But all that talk about angles and inches and cuts was worth it to protect a cute little guy from the sun! Here’s to throwing small mammals – but doing it in the shade!

Kelly

If my math teacher had made math this interesting and this applicable to my everyday life, I might have learned something 🙂

I just love your tutorials! You always go outta your way to explain every detail to us. Your fab 🙂

Just wondering about why you decided to have the tower sit on top of the ground vs having tower supports buried.

We did it that way so we could move the playground if we need to, and so we wouldn’t have to buy cement or do that extra step. The weight of the playground holds the whole thing down pretty well and it’s not wobbly at all, so we didn’t see a need to bury them.

Aw, this was a really good post. Taking the time and actual effort to generate a superb article… but what

can I say… I hesitate a whole lot and never seem

to get nearly anything done.

I noticed in the first part of this blog there was a full list of materials but for part 3 and 4 that stuff wasn’t on the list is the anyway to get a hold full list for price checking and shopping around for the right materials

Thanks for the awesome plans, Andy! I’m planning on following this tutorial for our yard. I was going to change the dimensions a bit and was curious to hear your thoughts. Basically, I was just going to use 10′ posts on the corners instead of 8′ posts, then lift the floor up a foot. We had some concerns about stability, but I wouldn’t imagine a couple of feet would make much difference. Any thoughts?

I would like to thank you for teaching people how to use a framing square. I taught my son to use a 3,4,5 triangle to square the timbers on the ground for the 24’x24′ play area his new playset sits in. Today is roof day…wish us luck. (He wants me to use the entire 10’x10′ mesh tarp to “maximize the potential shade”, and he’s 6…)

Hey there, just wanted to let you know that I have searched the net for good DIY plans, and this seemed by far the most complete. I am in the process of building mine but noticed the rafter shape (parallelogram) seems wrong. Based on your pictures it looks like a trapezoid. Anyway, I was able to get all materials for ~$400 as well so my wife was quite pleased. Working on the tower now, the swings next weekend (hopefully).

This is the best DIY tutorial that I’ve ever read, and probably the most hilarious to. We’re wanting a play set for our two girls and we were kinda intimidated by attempting it ourselves. After reading this we’ve decided to give it a shot. I’m gonna modify it a little. Instead of a 4′ deck hight it’s going to be a 5′ deck. I’m hoping to later upgrade the slide to a tube slide which will require a 5′ deck. I’m also going to add monkey bars, and maybe a rock wall entry. Not sure yet. I want it to be fun and safe for both my daughters who are 6 years apart. As of right now my calculated cost is at $299 going through Home Depot. I still have to buy bolts, nuts, washers, screws, and the infant swing. I found something called Fastenmaster ThruLok that I might use instead of nuts and bolts. Haven’t decided yet, but we only decided yesterday to build it ourselves so I think I’m good.

Can’t wait to get started!!!!

P.S. If more kids realized they could use math in the real world like this they would probably enjoy it more.

I love your plan! It’s going to be so fancy! 🙂

How to add a roof to a DIY wooden playground/playset

Sounds creative stuff. Looks soo impressive!

Do you have a full bill of materials from start to finish. Trying to go back through all the post to count the added 2×4 and the little extra and just wanting to make sure we get everything on the first trip : ) Really excited for me and my husband to start to attempt to tackle this!

Just so you know this post is being read long after it was create, all I can is “This is what I have a husband for.” He would copy off my algebra I and Trig homework, I would copy his Geometry and algebra II. That is how I knew we were soul-mates. <3

Is this design sturdy enough to support adults on the swings? We want to play too!

Kelly,

I’m embarrassed, because I’m likely missing something obvious. But I can’t find the plans for the playset you guys made. Are there any beyond the perspective drawings and the photos? Any bill of materials?

Also, and of greater interest to me: How has it been holding up? I’m not so concerned about weather, but about a few years of forces being applied to it. Have you ended up anchoring it? Have you found it necessary to ad bracing to protect against forces not in the plane of swinging? Can you or Andy give it a hearty swing without getting nervous?

Thanks much!

I used your site as a reference to build a playset for my kids this summer. Thank you for the inspiration!

Hi, I noticed you used 2 brace boards under the decking on the one side and it looks like you put 2 x 2s around the top of the decking to screw the “slats” to. Is this correct? Great tutorial.

How would you add a climbing wall, monkey bars and firepole? (I Ean you personally.)

Hello! Hello!

It’s now 2020 and we just finished building our tiny home ( although the REAL finishing touch on the house we thought would be a swim set). Also, we are at what we are hoping is the end of the Corona virus pandemic… With that being said, it’s also been a everyone buy all of the swingsets and pools pandemic! We are SO incredibly thankful to have found this series of posts and to have found them after parts 3 and 4 had been added! We are so looking forward to starting this build (me. Honestly it will be primarily me doing the build and utilizing my hubs big – okay not so big- muscles). I love numbers and building so I’m probably going to get started tomorrow 🤣 thanks again!!