Building a Treehouse Without a Tree (on piers)
I am planning on building a cabin on tall peirs (next to, but without attachment to trees) that I want to have the appearance of a treehouse. Wooden poles between the pier bases and the girders such as ‘telephone/power’ poles. I would like to maximize the appearance of it being a treehouse. I am thinking to make it ten feet off the ground with a ramp up to it with perhaps six feet of vertical gain. It seems that I could support it on two girders under the load walls that will be approximately 24′ or shorter that are either glue lams, fitch plates, or steel. Then do a free span with wood I-beams that are 30” or shorter. This approach would have only six big-foot style concrete supports. I need to pay attention to the total load including snow at 80 psf just for the snow and it seems that six piers would support it but I haven’t determined the soil type yet. The lengths are my maximum permitted size. It is a lakefront project in New Hampshire. Of course there would be a need for angular reinforcing of the vertical wood supports and steel cable could make the appearance of the cross-hatching of wood go away.
Sewage and power would be easy but I would need a way to keep the water supply from freezing.
I would probably put in six inches of rigid foam underneath and them apply closed-cell spray foam.
Anyone with ideas to make it better or less costly?
Replies
Never seen a 24 foot treehouse.
Did you mean ..
Did you mean 30 feet? not 30"?
If I wanted to emphasize the "tree house" appearance, I'd consider having the telephone poles stick up above the structure at random (not equal) heights and having the roof be somewhat irregular in shape. Have some other members stick out like branches, perhaps.
Would take a fair amount of designing but an interesting concept. (If there's a archy school or art school near you you might see if students want to take on the design.)
Here you go.
Take from this what you will.
Pretty neat!
dan
In 2012 there was a treehouse theme of builds at the Cheekwood Gardens, Nashville. Sized for the young-but with adult supervision. This a maybe 2 other types still stand. All were meant to simulate "treehouses" w/o including or harming the trees.
If ever in Nashville, I recommend visiting-the gardens are beautiful and there's always something "happening" there.
Many gardens around the country have a reciprocity agreement with them-your memberships are honored there as well.
Here's some of the frame under.
Update
House will be about 22' x 28', two stories.
It will be raised about 10-12'
Fortunately the nearby trees will be close and make it look better. Worried that mounting on tree will be a big problem when it dies. One 8" tree through deck on lakeside. It will have look of real treehouse.
Hard part is putting heavy house on six piers. Guessing piers rated at 15,000 lbs per peir. More than six piers will make it look like I ocean-front pilings.
Perhaps mount on native logs with steel cables and perhaps different diameters.
Thanks for ideas.
If you use native logs, while it would make it look more "tree-ey", you do need to worry about rot on the bottom ends (and, to a lesser extent, the top ends). Even on top of concrete piers the bottom ends will tend to rot. So you'd want to use a rot-resistant wood and somehow treat the ends, plus perhaps have a strategy for replace/repair in mind from the beginning.
Some thoughts.
I once envisioned a similar project many years ago, so I'll throw in a few thoughts. All of them will probably involve some engineering. I don't know what you want to use this for or whether it is necessary to meet all code requirements. It sounds like a vacation home.
Keep the footprint of the foundation as small as possible. Cantilever the floors as much as you can. This will tend to conceal the under structure and foreground the surrounding trees. Consider treated lumber or steel columns set into concrete rather than on concrete piers; this will minimize the need for cross bracing. Plant extensively around the the base to hide the structure. You could also consider a concrete block or ICF foundation if you can hide it under a cantilever and with plantings.
Don't consider an open floor plan. Make each room its own little structure on its own level if possible. Each room could have its own roof. Rooms could spiral up around a central core. With multiple levels, each set of stairs could be unique. Use outside stairs as much as possible. If this is only going to be occupied seasonally consider making stairs open to the elements.
Vary window and door styles and sizes. Vary material treatments. Make it look as if you used a lot of found materials. Vary roofing materials. Vary railing styles. In short mix things up.
If you can plan multiple outdoor areas rather than one large expanse of deck. Each area can offer a unique experience to the users: breakfast in the morning catching the sunrise, afternoon cocktails (it would appear that the software for this forum doesn't like drinking, since it ridiculously censors the word for a mixed adult beverage), evenings under the stars.
Expose as many structural elements as possible.
Good luck. It sounds like a fun and creative project.
Good Thoughts
Good ideas. Good to call it a two-story piling house for the permit. I do have a picture of a treehouse that I am trying to emulate. The ramp really enhances it visually and since there is a slope already it helps. I think it was even shown in the New York Times some years ago. Visually it is stunning. I will use pilings either in concrete or driven. I hope for two rows and I'll use an engineer to see it can span the distance. Rocks and planting a will help. Need to see the lake under it. If not then easy street for three rows. I would love to hear from someone if they have done two rows.
I like the spiral separate rooms idea as something funky and creative but perhaps for another project.
I will have to do something interesting to keep the water supply from freezing (a well).
Use a pitless adapter in the well with the pressure tank within the heated house. You'll still want to insulate the water line but with no standing water freezing won't be an issue.
EDIT: Actually the pitless unit is simply a way to connect to the well without the line being exposed to freezing temps. What you really need is the corresponding valve at the pressure tank... the part that I can't recall its name. This will allow water to flow into the pressure tank when needed then keep it there while, at the same time, it allows air into the supply line thus letting the well water to drain back into the well casing. This system does not use a bladder type pressure tank. Instead it relies on the air that is pushed in front of the well water to enter the tank where it acts as the air cushion to keep pressure in the system. Sorry, its been a long time since I considered such a thing and details of the installation are fuzzy at best. A competant well guy will be of immense help to you.
Call it a "treehouse" if you
Call it a "treehouse" if you like but to the buidling department is will be a 2 story piling house. You can buy pressure treated round piles pretty cheaply and either dig or drive them into the ground. I'd want 3 rows of piles for a 22' span then the rest is just typical framing on made up girders or gluelams. Once the frist floor is down you're just building a two story house, no matter what it looks like. Have you considerd how long a ramp up to 10' will have to be?