Backyard Treehouse With Zip Line, Trap Door, and Sliding Door

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Introduction: Backyard Treehouse With Zip Line, Trap Door, and Sliding Door

About: Professionally I have been a summer camp counselor, a Draftsman/designer, salesperson, bicycle mechanic, laminate flooring machine mechanic, teacher, and designer of the OP Loftbed. Personally I am a human t…

I had been planning a treehouse, for the kids, for a while now. I originally wanted a true treehouse in a tree. There was a nice healthy oak tree in the backyard, that would have been perfect, if it hadn't been blown over during a very rainy and windy storm. So instead of a traditional treehouse, I made an elevated house amongst the trees. One feature that does use trees is the zip line that can be used to get up to and down from the porch. I am going to break the project into different sections to show you how I did each part. Hopefully you can learn from my triumphs and mistakes and use this information to help you make your own backyard treehouse.

Supplies

A collection of your average woodworking tools, saw, hammer, drill, impact driver, sander will be needed to build a backyard treehouse. Since this was high off the ground, I used a couple of ladders. I even bought a new tool; a power planner to plan some rough cut lumber to recycle into smooth usable wood. Some wrenches were needed for the cable clamps on the zip line. I used post hole diggers to dig the holes for the support posts and a shovel and wheelbarrow to mix the cement for the posts.

Step 1: DANGER!

As with most of my projects, there is always potential for injury. I fell from a ladder, found a hornets nest, got sunburned, almost got struck by lightning, strained a few muscles, and got dehydrated. Be safe. Wear safety glasses, gloves, hearing protection, sturdy shoes and take your time. This is a big project and will take several days. Plan ahead for potential safety issues and avoid injury.

Step 2: Zip Line

One of the main features that I wanted to include was a Zip Line. We had a treehouse with a zip line growing up. My sisters and I survived our childhood so I thought that my children could use the experience of fun and danger that a zip line can provide. I picked two sturdy trees and installed a Zip Line.

I have made an Instructable on a Zip Line Swing that can be seen here: https://www.instructables.com/Zip-Line-Swing/

Step 3: Location, Location, Location

I wanted the zip line to be in the center of an opening on the deck of the treehouse. Since the trees that the zip line are attached to determined the location of the zip line, I used the zip line to determine the location of the treehouse deck. I used a chalk line as a plumb bob to mark the ground directly under the sip line. I then measured off of this mark to mark where the post holes should be.

Step 4: Dig Holes

Some people will say a PHD (post hole digger) is too expensive and not useful. Trust me, a post hole digger is not that expensive and I think is the best tool to dig a hole for a post. There are different ideas on how deep a post hole needs to be. I just dug till I hit rock, tried breaking up the rock to dig deeper, and then stopped when the rock layer was too hard to break up.

Step 5: Plumb Posts

I rigged up a series of boards screwed to the posts to hold them in position and plumb so that they would not move while the cement was being poured and set up. These boards would be removed after the cement set up.

Step 6: Cement Posts

I mixed up the cement and then used a shovel to carefully pour it into the holes around the posts. I waited a few days to give the cement time to fully set up before continuing on with the rest of the treehouse.

Step 7: Floor Joists

I framed out the floor joists level and cut the support posts even with the top of the floor joists.

Step 8: Gussets

Once my floor joists were in place, I decided that the structure was a bit wobbly. I used 4x4 posts instead of 6x6 posts because they were not as expensive. The 6x6 posts would have probably not been as wobbly. To fix the wobbly problem, I decided to install gussets. I made the gussets out of 2" x 3" wood that I had reclaimed from runners used to ship goods on. I made a 90 degree corner on one end and a 45 degree cut on the other end. I used a piece of plywood to position one end flush with the top of the floor joists and positioned the other end on the post. I screwed scrap triangle pieces (from the 45 degree cut from the end of the gussets) at the connection to the posts to both reinforce the connection and to prevent an entrapment hazard at that point. I also made a ladder for the hidden trap door on two of the gussets. The gussets solved the wobbly problem and added an artsy look.

Step 9: Deck Floor and Trap Door

I used treated decking wood for the deck section of the treehouse floor. I used treated 3/4 plywood glued and screwed to the joists for the inside floor section. I wanted a secret trap door in the back corner of the treehouse. I framed out the trap door section of the frame and temporarily placed the 3/4" plywood to trace the location of the trapdoor frame so I could cutout the trapdoor. I used a jigsaw and made plunge cuts so that the trapdoor grain would match the rest of the grain on the plywood floor. I installed a piano hinge on the trap door. I later installed a door latch that could be used to lock the trap door from the inside and also safely hold the door open by latching it to the wall.

Step 10: Deck Cutout for Posts

I knew that I would be adding posts for the corners of the deck and for supporting the roof over part of the deck. I cut out the deck boards in these locations, so the posts could rest directly on the floor joists and posts underneath.

Step 11: Free Wood, Worth It?

I had access to some free wood. It was rough cut so it would need to be planned to be nice looking and splinter free in places that it could be touched. I bought a power planner to smooth down all the boards. It took me two days and four sets of blades on the planner to get all the boards smooth. I used some of these boards rough, in the rafters, where the boards would not be touched and they gave a nice rustic look. I could have just bought boards but I think it was worth the effort to reuse these boards that would have otherwise been in a landfill.

Step 12: Planning Jig

I found holding the boards steady to plane a chamfer on the corners difficult so I built a crude jig to hold the boards in place. I made an Instructable of this jig here: https://www.instructables.com/45-Degree-Board-Holding-Jig-for-Chamfer-Planning/

Step 13: Storms!

There were numerous storms over the course of the summer that I built this treehouse. Some things I could plan around like cement in the post holes on a week that was forecast to be dry. Other times I had to prevent water damage by temporarily installing sheets of plastic and tarps.

Step 14: Framing Walls

After planning all the free wood smooth, I used it to frame out the walls. Three of the walls I framed out to have two windows. I have only installed two windows on one of the walls but having the framing in the other walls would make it easier to install windows in the future. I made the walls laying flat on my concrete driveway. I then laid them flat on the floor of the treehouse and attached the outside plywood sheeting on to the walls. I then raised them into place and held them in place with some temporary boards. I decided that the back wall would be easier to raise into place and add the outside plywood sheeting.

Step 15: Door Wall

I made the frame for the sliding glass door wall, the same way as the other three walls, laying flat. I used the frame of the sliding glass door to layout the lumber for the wall. This wall was a bit heavy but we were able to get it and the other three wall sections up to the treehouse by using the zip line like a ski lift which was much safer and easier than carrying them up ladders.

Step 16: Rafters

I used the same technique with the rafters as I did with the walls. I used the same 2x3 reclaimed boards as the walls but left them rough since they would be high enough that no one would touch them. I laid them out flat on the driveway and fit them on the wall frames. I designed them to have a 2x6 ridge board. I used a small birds mouth cut for where they would sit on top of the side walls. I made center support boards for the ridge board at the front and back wall and also at the roof end support that covers half the deck. I installed those six rafters with the center supports first to help hold the ridge board in place and then installed the rest of the rafters.

Step 17: Ladder or Stairs? Both?

Out of all the elements of this treehouse, the stairs/ladder design haunted me the most. I finally decided that I wanted both. Basically I ended up making really steep stairs with one handrail. I decided the angle of the ladder stairs (35 degrees) by holding a long board, one end on the ground and leaned it up against the deck so that it would just clear the fence in our backyard. I used 2x12 stringers and cut dados in them for the steps which I glued and screwed in. On one side, I cut the stringer flush with the deck. On the other side, I used a birds mouth where the stringer would go up to join in the guardrail post on the deck. I made vertical pieces to hold up a handrail that also connected to the guardrail post on the deck. I dug a trench and lined it with gravel for the bottom step to rest on. These ladder stairs probably violate multiple building codes but the size of my treehouse didn't need a building permit, where I live, and they have been working fine. I just wish I had decided on the design earlier because it would have come in handy to have them in place for the rest of the treehouse construction.

Step 18: Metal Roof

Of course when I was building the rafters and installing the metal roof, rain started. I put up a tarp to keep everything dry. In between rain showers, I could roll back the tarp and install sections of roof and then roll the tarp back on as the rain started again. I put some horizontal cross pieces between the rafters to support the metal roofing and give me something to screw the roofing to. I used a pair of small vice grip plyers tied to a cord so that I could pull up the metal roof sections. Once up, I would use the same vice grip plyers to hold the roofing piece to the previous roofing piece. To help keep the screws even and lined up, I used the tape from a broken tape measure, taped magnets to it and hooked it right beside where I would be placing screws. Ticks were crazy this summer and they were crawling to the highest point of the treehouse looking for a host. I finished off the top of the roof with a matching ridge cap.

Step 19: Staining

I used deck and siding stain to stain the outside sheeting of the treehouse. I put small amounts of the stain in an old plastic container to have something lighter and in case I dropped it, I would not loose all of the stain.

Step 20: Sliding Door

A sliding door may sound like a bad idea for a treehouse but I think it is better than a regular door. A regular hinged door with a hinged screen door would take up room inside and outside the treehouse. A sliding door doesn't need to swing in and out leaving space inside and out free to use. At first the sliding door seamed too expensive but it cost the same as a door, screen door, and window, which is what I was originally thinking of putting on this wall originally. The instructions that came with the sliding door placed importance on having a good level and square opening so I made sure the opening was perfect before installing the door.

Step 21: Windows

I drilled a hole in each corner of the opening for the windows in the outside sheeting. I used a sawsall to cutout the siding. I caulked and screwed the windows into the openings. I then used treated 2x4s ripped to 2x2s to make a frame around the windows.

Step 22: Hinged Gable Vents

I had intentionally designed the roof of the treehouse to have a large overhang on both ends of the treehouse. One end covers half of the deck but the other end overhangs to keep weather out of the gable vents. I originally thought that I would just have a screened opening at each of the gables. I thought of a way to be able to allow more or less air to pass thru the gable vents by having hinged doors over the screened openings.

I started by cutting triangle shaped pieces of exterior siding to cover the gables. I temporarily screwed the pieces in place. I then traced where the frame pieces of the gables were on the triangle pieces. I used these lines as guides to mark the cutouts for the doors 3/4" larger than the triangle opening in the gable frames. This would make it so the triangle gable doors would use the gable frames as a door stop.

When cutting out the gable doors, I started by cutting the hinge side first. I then installed the hinges and then gut out the rest of the doors.

I used a trick to make the hinge screw holes line up with the hinge holes. I used a drill the same size as the holes in the hinges to match drill a shallow hole in the siding. This shallow hole would act as a center punch to guide the proper size drill for the hinge screws.

Before putting up the finished gable vent doors, I stapled some screen material to the gable frames.

After installing the gable vent doors, I used screw eyes to fasten a cord to the corners of the gable vent doors. I passed these cords thru some other screw eyes that I used like a pulley to be able to open and close the gable vent doors. I screwed some screws part way into the posts to use as cleats to wrap the cords around to hold the gable vent doors in place. I can open up the vent doors in hot weather or close them for cold weather.

Step 23: Rails

I used treated wood to make rails around the deck of the treehouse. I used local code to make sure the railing would be safe. Spacing between the vertical pieces is important to keep from having an entrapment hazard.

Step 24: Hammocks

I used some purpose built brackets to hang two hammocks from opposite diagonal corners of the wall frames.

Step 25: Conclusion

I built this treehouse during the Summer of 2020. It was a long project that kept the whole family busy and entertained during a time where the whole world seamed to be at a standstill. There are a few things I would do differently, if I were going to do it again, but for the most part, the treehouse has worked perfectly. The kids love playing in it and we have even had "camp outs" overnight in the treehouse. When the kids grow out of it, the treehouse could be converted into an office or spare room. I hope this will give you some ideas to use on your own treehouse. Thank you for viewing my Instructable.

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    27 Comments

    1
    CMoz
    CMoz

    6 days ago

    Such an amazing project - and love that you could use it as an office in the future!

    0
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 6 days ago

    Thank you for your comment.

    0
    marco.consumi1
    marco.consumi1

    8 days ago

    Very great project, thanks for sharing. Just a question about the use of cement in contact with wood, someone thinks it is not a good idea, but the issue is controversial, what's your opinion?
    best
    Marco

    0
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 7 days ago

    Thanks for the comment and question. The tree house my grandfather and dad built for me and my sisters had treated poles cemented in the ground. That tree house lasted 25 years. The wood in the structure had started rotting and was unsafe. We tore down the tree house. We pulled the poles out with a tractor. Two of the poles snapped at the top of the cement while the other two pulled the cement out of the ground. There are other ways to make a pole structure that would last longer and be easier to repair, but for time and money invested, holes and cement is what I chose.

    0
    mwitherspoon
    mwitherspoon

    Reply 8 days ago

    I see a lot of projects these days setting the
    timber directly into the cement. People claim the pressure treated lumber
    is ok to put directly into cement. BUT the reality is its only better
    that non treated lumber, but still not a good idea if you want it to last as
    long as possible. And it may depend on
    your local codes.

    Having recently totally demolished and built
    new, an elevated deck off our second floor dining room. Because the support beams literally rotted
    out right at the cement joint, which was just below ground level (many code
    violations there by whoever built it).

    Building codes in my city required (at the time
    of my rebuild), cement piers extending below the frost line (laughable as I’m
    in Phoenix AZ, we don’t have a frost line) and extending above ground level to
    at least the foundation line and the supporting beam to be attached to that using
    proper brackets and ties. The second benefit
    with this method is, you can if necessary more easily replace this support beam. Which I might have done with the previous supports
    long before, except that the time and effort added to the desire to have a bit
    larger deck had me waiting until I had a sabbatical to demolish and rebuild the
    whole thing.

    0
    marco.consumi1
    marco.consumi1

    Reply 8 days ago

    Thanks for your exaustive answer. Actually I'm in Siena and sometime we have frost during the winter but not a frost line maybe. Anyway the advice from the landscapers are use chestnoot-wood directly in the ground without cement at all or use metal attachment to fix the wood to the cement by resin. In any cases avoid the wood directly in the cement. Of coure I'm not an expert so that's my 2 cents and probably the chemically treated wood is different. Thanks for sharing best regards

    1
    ldraconus
    ldraconus

    8 days ago on Step 25

    Hejh, really nice fort you've bui;t there (my inner child is very jealous), but a tree house needs to be in a tree ... just saying

    0
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 7 days ago

    I had picked out a really big and strong looking oak tree to build a tree house in, and it got blown over in a rain storm. You can see the stump in some of the photos, just down the hill from the tree house. Probably good that I procrastinated.

    0
    mwitherspoon
    mwitherspoon

    8 days ago

    Great job on that! Looks great and should last a while.

    0
    QuentinB1
    QuentinB1

    8 days ago

    Fantastic design and great idea for pre-framing the future windows.

    Only thing that I would suggest is using nails for the all the times where you are attaching 2x4s etc, anything structural.

    Screws may be easier, etc, but Nails are stronger. If you want to, you can use both.

    Screws are great for resistance to pulling out of the wood, but they have next to no shear / sideways strength.

    To see this for yourself, stick a screw into a piece of wood, and hit it sideways (with a hammer), and then stick a nail into the same piece of wood, and hit it sideways.

    Now, straighten them out with one hit from the side as well. The nail will straighten, and be just as strong. The screw will snap right off.

    Now, imagine if your kid(s) are jumping around in there, smashing into walls, whatever. Which of those two fasteners would you be trusting?

    Attaching flooring to the floor joists? Screws. Attaching interior finish to the studs? Windows to studs? Screws are fine.

    Anything else, use nails. Even the exterior cladding, if it's providing structural strength (this small of a shed, the walls are holding each other up, so the exterior cladding isn't quite as critical)

    Also, if you had erected the rear wall first, you could have sheathed it laying down on the deck as well.

    If you take the time to do the hurricane ties, like others have suggested, the nails used for those will help, but I would still be walking around and throwing at least one nail in every framing junction, if you can reach them.

    1
    photony
    photony

    9 days ago

    Former kid here. We built a LOT of tree-houses and forts growing up. Every one was with found wood and straightened-out nails. You built a she-shed for your kids. Sorry, but that doesn't qualify as a treehouse in my book.

    1
    mwitherspoon
    mwitherspoon

    Reply 8 days ago

    While not technically a "treehouse",
    which he admitted to right off. It all depends on ones needs. I'd
    bet first and foremost he wanted something safe for his kids to play in.
    And secondly something he didn’t need to make constant repairs on to keep it
    safe. Trees move, ALOT, and that movement is bad for a structure, especially
    a structure this large. This movement
    tears apart the structural joints, making it less safe and requiring more
    repairs. Such repairs can be quite
    extensive as the wood near the joints becomes fractured, or cracked, requiring
    ripping out entire beams, and that’s a lot of work. Not to mention that treehouses can cause irreparable
    damage to the tree.

    1
    photony
    photony

    Reply 8 days ago

    I can concur...I HAD a treehouse for 25 years in a 60 foot oak...until a summer storm toppled a third of it. I have 2 50 foot maples that I'm eyeing, with 25 years of experience to help me...BTW...I'll be 70 on my next birthday, and the treehouse was for ME!

    1
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 9 days ago

    I have also built treehouses with trees that we cut down and used metal wire to tie them to the tree. I am surprised that we survived our childhood. One of the reasons I was able to justify the expense of the treehouse was that I told my wife that, once the kids outgrew it, it could be an office. And I don't know if you noticed but the studs in three of the walls as well as the rafters, were all free reclaimed wood from my work that would have otherwise been "recycled" (sent to a wood chipper). Thank you for your comment.

    0
    bluelily17
    bluelily17

    9 days ago

    What a great instructable! I don’t have trees in my yard and have been thinking of making a platform tree house that can be used for years as the kiddos get older. This gives me a few ideas when planning my own project. Thanks!

    0
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 9 days ago

    Thank you so much. I would love to see a few pictures of what you end up making. Maybe make an Instructable of it.

    0
    MerlinTheGreat
    MerlinTheGreat

    9 days ago

    Nice work. Looks good too.
    I would insulate the roof since a metal roof lets in the heat in summer and the cold in winter.
    Maybe while you're at it, you could also insulate the walls and possibly the floor. Then cover it up with thin plywood board. That'll save you work if you want to give the thing a new destination. Plus it will be nicer to stay there overnight.
    Thumbs up !

    0
    CHARLESCRANFORD
    CHARLESCRANFORD

    Reply 9 days ago

    I was thinking that I could make those improvements later in the future, especially if I convert it into an office. I added the gable vents to let out the heat plus it is in the shade, with all the leaves on the trees, during the summer. Sleeping overnight in the treehouse is more like camping in a big tent. Rain on the metal roof sounds cool. Thank you for your comment.

    0
    JimOfRedlands
    JimOfRedlands

    9 days ago

    Great project! We had a Zip-line in our back yard for many years. We learned that trees move so the line must be able to handle that.
    We used a cable winch at the bottom. We would keep it loose until we planned to use it. We would then tighten the steel cable to make a fun ride. After the fun was over, we would loosen it again so the trees could freely sway in the wind without ripping apart our Zip-line.
    The ability to make the line tight or loose also made the experience adjustable. A looser line was simpler for smaller people while the tight line was more thrilling for bigger people. While the line was tight, a smaller person would not have been able to touch the ground before slamming into the tree trunk.