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How to build a treehouse

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This particular design requires two or three trees (or branches) in close proximity. It was made over the course of several weekends using new, pressure-treated wood for the support structure and floor and an old fence was recycled for the sides. The roof is a camouflage-pattern tarp. It's not weather-proof, but it stays pretty dry inside: a three-season treehouse, but best for summer! It was made with my 4, 6 and 8-year old children in mind, but has been a hit with visitors of all ages.
 
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Step 1: Pick your trees

There are definite advantages in using more than one tree for your treehouse - the treehouse can be bigger, and you have to use less bracing. The tree(s) you see here (behind the magnolia!) are a very tightly grown group of three trunks - they all touch at the base, and splay out somewhat as they grow upwards. At the height of the treehouse - about 9 ft (2.7 m) off the ground - one pair of trunks are still almost touching, and the other one is about 4 ft (1.2 m) away. This means the design has been based on one for a close-spaced pair of trees, rather than for a group of three. The trees are Garry oaks, and they don't grow much further north than this (southern Vancouver Island), so they grow pretty slow here. A solid gnarly collection of old trees, each about 1 ft in diameter at 9 ft up.

Start by figuring out how high you want the treehouse. 9 feet is exciting for kids but not scary. You can of course go higher, but you'll have to take more account of movement.

Thanks so much! I had already started all wrong and after seeing yours with the 2x10 underneath and freeing the 2x8 from the tree movement I was able to do a quick fix to make mine much sturdy. Thanks.

kurtzepp8 months ago
Thanks for you insight. I used your plans as a source. Although my treefort does not resemble yours on the outside, it does have some similarity.

Here is a link to my Treefort: http://kurt-zeppetello.blogspot.com/2013/08/tree-house-or-fort-construction.html
makendo (author)  kurtzepp8 months ago
Nice job, it looks great. You should consider writing it up as instructable (you've done all the work already!) and entering it in the Fort contest on right now.
rcotnam10 months ago
Sorry, I see someone else asked this below, and you answered it!
makendo (author)  rcotnam10 months ago
Ha, well spotted, I'd forgotten myself. The fact that two people asked means I probably should edit that step to explain myself better...
rcotnam10 months ago
How can rafter ties be used when the angle between the "perpendicular" 2 X 6 boards is not square (i.e. not perpendicular at all but several degrees off)?
makendo (author)  rcotnam10 months ago
If you look at the first photo in Step 8, you'll notice that the rafter tie is not flush to the wood as I'm nailing it. However, it provided very little resistance to widening the angle beyond 90°, so I guess I just hammered it open slightly as I was nailing.
jcdecker711 year ago
Just wanted to reach out and say thanks. My 11 year old son has been bugging me for a year for a tree house, and while I'm okay with tools, taking this task on was proving daunting. These are great instructions and I have modified based on needs. Got the joist attached to the tress today. Moving on to the frame next weekend. Thanks!
makendo (author)  jcdecker711 year ago
Thanks, I appreciate it. Best of luck with the build; let me know if you have any questions as you go along.
Good Father. Congratulation!!!!
dclose731 year ago
Question about the rafter ties. In my configuration, the 2x10s and 2x6s are not at right angles. How did you manage to attach the rafter ties? Did you somehow bend each of them to match the angle of the join? Or were your angles close enough that it did not require any modification?
makendo (author)  dclose731 year ago
Mine were pretty close, and yeah, I just hammered them flat. Good luck with the build!
this how-to was really easy to follow. cool stuff. The attached images showed my finished product. Kids are having a blast!
Just need the basket with the pulley now, and perhaps a zip line.

All fun stuff. Thanks,
DSC_0257.JPGDSC_0271.JPGDSC_0289.JPGDSC_0310.JPGDSC_0315.JPGDSC_0320.JPGDSC_0328.JPG
makendo (author)  pedrozacharias1 year ago
Great job! Looks really good, and you have pretty much the perfect tree for it, too.
zilcho1 year ago
That is a legit tree house
this is great my dad keeps on saying he will make a tree house he never does
HollyMann2 years ago
You have some very lucky/fortunate kids to have a dad to make them so many awesome things! I love all your instructables - esp the bed - this one and the rubik's cube drawers! AMAZING!!!!!
makendo (author)  HollyMann2 years ago
Many thanks Holly, glad you like them. Making things for your kids is super rewarding, as no doubt you've found yourself!
I have 10 aceres. about 2.5 is forstry. I have 2 forts. 1 in the trees and 1 on poles me and my sis have wars. im still upgrading my forts with rails, shelves, airsoft gun turrets, ext
And i keep a dune buggy under it
what about grenades

that sounds absolutely incredible man, kudos to you
Winter-_-2 years ago
yikes. So many posts with people telling you off about how you did something or even someone just grumping about you "hurting trees" it has to be anoying- but im so impressed wih how each of your comments back are kind and to the point! :)
Its just so nice to see that even when others are being rude to you (and thats crazy as it is seeing that your posting a free gide and if they dont like it they can move on) your not lashing out.
Looks to me like your kids have two things to be proud of, a wonderful treehouse, and a dad who acts like a kind and levelminded adult. <3
makendo (author)  Winter-_-2 years ago
Aw, shucks. Thanks. The vast majority of feedback on this site is positive, fortunately, but this ible did seem to get some people quite indignant - probably for the wrong reasons. The same people don't seem to mind projects built out of dead trees! :)
cghale2 years ago
I'm at this point and am wondering the same thing as andrew...how do you attach the 2x4s to the platform? Deck screws or something more substantial?
makendo (author)  cghale2 years ago
Deck screws are fine; just drive them through the 6x2 into the 4x2 brace. The decking sits on top and also helps secure the brace.
cghale2 years ago
For a house like this, what would the maximum safe width be? (i.e., between two trees) Working on this design now...
makendo (author)  cghale2 years ago
Not far at all. These trunks are within four feet, and don’t move much at all with respect to one another. If that’s not the case for you, taking account of movement is really important. The slots accommodate only a small amount of movement. If I was making a more widely spaced treehouse, I’d sit one end of the main supports on top of two really big lag screws (3/4” or bigger). There is a place you can buy them online now - http://www.treehousesupplies.com/. The other end could be screwed directly to the tree, as I show here. Good luck with your build!
More bolts, in slots, please.
Three per tree in each board are recommended.
Two would be better than what you have.
The problem with your application is that the trees in high winds can exert a HUGE horizontal torque force on the bolt heads that could bend, tear out, or shear them.
What we did in our very similar situation was to drill several holes (just a bit bigger than the bolt diameter) next to each other in the boards.
ooo
Then we chiseled them out into slots.
(___)
Then added a bolt with a BIG washer in the middle of each slot.
(_O_)
This design allows the trees to move in high winds independent of each other without snapping or bending the bolts.
Also the bolts should NOT be tightened. The washers should be able to rotate. This allows the bolts to move side to side in high winds, and for the whole structure to "give" a little.
If you think of the tree as a huge lever, and the distance the wind can move it both ways, you start to understand the amazing forces at work here.
We love your treehouse.
Come to think of it, we love all of them.
makendo (author)  Ricardo Furioso3 years ago
I disagree about the "3 bolts per tree per board argument" - see this page for why. As for the rest; read step 4.
Whooops.
You're right about Step 4.
cowmanpoke4 years ago
 in step 4 when you bolt the wood to the tree, are you drilling all the way through the branch? i'm confused about how that wood is staying on
makendo (author)  cowmanpoke4 years ago
No, they go in about 4". A lag screw is basically a giant screw with a bolt head on it. So the thread holds it in place - in fact, once you've put it in it is very hard to move again. Use the biggest ones you can find, and perch the supports as far away as you can while still being structurally sound. In this treehouse, the supports are only about 1/2" away, because the trees are mature and slow growing.
Honestly think you might rethink the length of your bolts.
A foot, yes 12-inches, would be recommended.
Why?
Because that treehouse may outlive all of us.
Because kids will be in it.
Because kids will invite their friends.
Because whole scout troops or classrooms full of kids might descend upon it (both have happened to ours).
Because adults have a habit of frequenting treehouses along with refreshing adult beverages that make them do silly dangerous things. In groups.
So.
I beg you to grab your socket and ratchet set, remove the 4-inch bolts, and replace them with big fat 12-inch galvanized lag bolts.
They're cheap.
It may sound like overkill, but the wind forces on treehouses are staggering, and if a storm weakens them, the next kids who venture up there could be in serious danger.
It is one thing for a kid to fall out of a treehouse.
It is another to have the treehouse fall or fail with a kid inside.
Thanks for considering this.
ricardo
makendo (author)  Ricardo Furioso3 years ago
I appreciate that you're anxious about the children, but if the treehouse is going to fail, I suspect it will do so during a storm, and it is not occupied during such events. It's survived over a year without any untoward events despite some overloading you'd doubtless be appalled by and a 110 km/h gale. It certainly won't outlive all of us, as it will be removed when my kids grow out of it.
A 12" lag screw would go clear through the tree (especially if I put in 3 per board per tree, as you counsel; that would seriously compromise the structural integrity of the trunk). As for the "cheap big fat lag bolts" - perhaps you can point out a source for the benefit of others? I certainly couldn't find them in hardware stores or even online; the pros have them custom-made.
Congrats on the gale survival.
I suspect you're right about the failure.
I hope you are.
We found huge cheap lag bolts at Home Depot.
Putting a bolt through the trunk shouldn't compromise it's integrity. You'd need to predrill it, and the great percentage of the trunk—excluding the live cambium which comprises the outermost layers—is dead wood anyway.
http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/text/tree_anatomy.html
Putting two or three bolts in a tree trunk vertically is a good solution if you do not have access to a custom fastener fabrication shop.
And it works just fine if you loosen the bolts annually to allow for growth and space between beams and trunk.
Werner1113 years ago
I would have added another bolt in for each tree, but it looks good :)
makendo (author)  Werner1113 years ago
I'm pretty comfortable with the bolts as they are for this little treehouse, but overengineering is no bad thing either. Better than putting extra bolts though would be to use bigger ones; this page explains why really well (and also points out that 1/2" lag screws are insufficient!).
Anyway, thanks - and I can confirm the treehouse is still standing :)
How do you secure the top of the bracing to the platform? Beneath it, on the outside, inside? I'm 15 and I have no idea what I'm doing... but decided that I really want to make a treehouse.
makendo (author)  andrewbhorton3 years ago
Beneath it and on the inside. Check out the hand-drawn plan and the second photo in step 9 (you can *just* see it). There are lots of other resources out there - on the web, books, etc. Best of luck in your build!
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