Landscape Timber Playhouse

This is the version I built. It was modified with an extra window
and served as one end of two swingsets extended from opposite ends.
I bolted one end of the crossbars to the top of the cabin and
built legs for the other ends. Then I bought some swings at
Home Depot and hung them up - easy peasy.

I built one of these playhouses for our day care center in Keene.  It passed the licensing inspection for child care centers at the time.  Since then, they've found harmful chemicals in some pressure treated lumber (which this was not), but most landscape timbers use non-toxic treatments these days so if you buy new timbers you should be fine.  You may want to check what they are treated with.  You can often find landscape timbers pretty cheap. I use 65 timbers I got for $2 each untreated.  I build this fortress-like playhouse for our day care center.  It withstood the attentions of up to 25 hyperactive kids at a time for 7 years and may still be standing for all I know.

Keep two things in mind when you build a playhouse, especially if you have homeowner's insurance or are an easy target for a lawsuit.  You need to keep a clear view of the kids at all times, especially when they are inside somewhere they think you aren't watching.  Kids experiment -- 'nuff said.The other important factor is sturdiness.  Children have way more time than we do and for every minute you spend building the thing, they have hours in which to figure out how to dismantle it.  This house is over-engineered and there's no real blind spots in it.  When you go to tear it down, you may have to blast.*

FIG: 1   Lay out the first two timbers

Materials:

• Sixty five eight foot landscape timbers
• Wood filler
• Five 7 foot long half inch all thread rods
• 18 half inch washers and nuts
• Two sheets water resistant marine plywood
• Box 3 inch galvanized screws.
• Forty six inch nails

 

FIG 2   Bolt the rods through the end holes

Tools:

• Sander and coarse sandpaper
• Drill and half inch and ¾ inch drill bits.
• Circular saw  
• Socket set
• Hammer
• Square
• Tape measure

FIG 3  Add the second pair crosswise.

Step 1 - Preparing the timbers

Drill a half inch hole through 36 timbers, 4 inches from the ends in the center of the flat side.  The rest you will leave for the roof and to cut for window and door spacers.

Step 2 -Remove splinters

Sand all logs and fill holes or splintered areas with wood filler. 

Step 3 - Set up the base and rods

Lay two timbers on the ground 6 and a half feet apart to start your stack.  Insert the four 7 foot all thread rods through the end holes and attach nuts and washers to the bottom with the rods sticking up.  

FIG 4  Add a rod for the door as shown.

Step 4 - Thread the upright rods

Lay timbers across the ends of the first two timbers, threading the upright rods through the end holes of the two new timbers. You are going to keep stacking them domino tower fashion so that there will be a gap between each row so you can see into the playhouse from every side.  But don't get carried away yet.  You have to build a floor and a space for a door first.

Step 5 - Set spacing for the door

FIG 5 Lay floor joists

Drill a half inch hole centered vertically, three feet six inches from the end hole along one side as shown in FIG 4.  This makes a gap in the wall for a door.  You will cut the timber on that side three ft 6 in. shorter and drill a hole six inches from the cut end.  This should leave you a three foot wide, wheelchair accessible "door" for entry and egress.   

Step 6 - Set the door rod 

Insert the 5^th long rod for a door frame and bolt it on the bottom.  Don't forget the washer.

Step 7 - Lay the floor

FIG 6  Screw floor over joists

Lay 5 undrilled timbers beside each other spaced evenly between the two timbers that make the second row to make floor joists. Toenail the joist in place and cover with plywood to make the inside playhouse floor. This will protect little toes from splinters you'd get with a timber floor and you can put a thick coat of paint over it to make it even smoother and safer and more water resistant. Screw the plywood into the joists and the floor will be very solid and help keep the playhouse framework from shifting around as the kids climb on it.

Step 8 - Cut spacers
Cut a timber for the third row that's 3'6" shorter and drill a hole six inches from the cut end through the flatter side of the short timber.  Cut several spacer logs that are six to ten inches long with a hole drilled in the center. 

Use the spacers as shown to serve as cross members around the edges of the window and door frames as you build upward. It should take about 7 more short timbers just like the first one to frame the door.  Because the door is next to a side wall, the spacer will form part of the corner of the structure and doesn't require a separate threaded rod. Just slide the spacers down over the rod on every other row between the end logs. Remember you're leaving gaps between the rows for a reason - you want to be able to see the kids while they are inside the playhouse.

Step 9 - Start the stack and set window rods

Criss-cross the ends of the timbers back and forth by threading them over the vertical rods as shownt.  You can see where we use two shorter rods and spacers to cut and frame for a window along the back side opposite the door.  In the illustration you can see how the door is framed. The picture shows the spacers on the right side of the door in line with the wall.  I placed them perpendicular to the front wall to give it a more log cabin look. For the window, just build up adding spacers till you run out of rod, bolt it off top and bottom. Make it tight, cut off the excess rod and then use full length logs the rest of the way up.  

Step 10 - Finish stack and add roof

Finish criss-crossing the logs till you get almost to the top of the corner rods.  For the last row, lay a solid layer of logs between the top two cross members until you have a solid roof. I didn't use plywood to cover the roof. You could, if you want or you could even add a pitched roof.  I found the flat roof fine. The playhouse is not designed to shelter anyone during a rain storm.  It's made for boys to climb on, conduct epic battles from and for girls to play house.  Screw or nail the roof logs in place to keep the kids from pulling them off and dropping on each others' heads.

Step 11 -  Install roof and recess bolt heads
Complete the roof installation  by bolting a final  two timbers across the solid row of roof timbers as shown at the right. Once it's all bolted together, cut off any excess threaded rod to prevent injuries to the kids (they will climb on the roof).  I inset holes in the top of the keeper timbers where the rod holes are.  I used a paddle bit wider than the bolt head and cut a recess for the bolts, then screwed the bolts in tight and cut off the rod.  That way the bolt is out of the way and doesn't protrude where it can catch feet or hands.

Step 12
If you'd like to make a table or a bench inside, you can lay a couple of extra logs side by side in the space between two ranks of cross members. Push them in and pound them up against the wall to create a ledge one or two logs wide running the width of the cabin. It will reduce the inside floor space somewhat, but will give the kids a sitting place and a place for pretend cooking or workshopping.

Take Note:

• Use landscape timbers that have been manufactured in the past decade. Toxic chemicals were used to pressure treat some older landscape lumber. Since the turn of the century, manufacturers have used non-toxic chemicals in treating them for durability and insect resistance.  
• If you use untreated timbers, spray them with a good, non-toxic water seal every two or three years to protect the timbers from rot.
• Surround the cabin with a 4 inch deep layer of pea gravel or sand. Pea gravel is actually better than sand at cushioning a fall. It's looser and displaces more easily when something falls on it. Also, pea gravel doesn't compact like sand into a hard surface.
• Keep the gravel smooth or the kids will wear it down in spots and reduce the fall protection. 

© 2013 by Tom King

* Turns out I was able to dismantle this in about half an hour and rebuilt it in a new location in about a half hour.