I am going to be building a Treehouse soon, and am researching the best and most cost effective means to do so. I am good on the platform and beams (using Treehouse Attachment Bolts), and am going to use 45 degree knee braces for additional stability.

They make some great Knee Brace Attachment brackets, but man are they pricey. Almost $100 each, and we'll need four of them. Also mentioned at this tree house guide. When reading some books, and other online resources, I see mention of braces that are more like Joist Hangers. But rather than having numerous nail holes like traditional joist hangers, they are supports by a single lag screw. They are referred to in these resources as "Framing Connectors" or "Hold Down" brackets. Does anyone know the real name for these, or where to find them? Asides from having some fabricated myself, anyone know where to find these?

Like this:

enter image description here

As seen here: http://www.instructables.com/id/Building-A-Treehouse/?lang=pt

I also saw these in the popular tree house book by black and decker: enter image description here

4 Answers 4


I think those are Simpson Strong-Tie HD3B, or maybe a HD5B. At under 10 bucks a pop, you can probably afford to buy one just to look at it and see if you think it suits your needs.

edit: just looked at the fancy $100 ones, and I can see how you get way better attachment from them. I suggest you integrate a strap that ties the bracket to the underside of the brace, as a single lag through the bottom of the simpson isn't going to be stellar at resisting a force that pulls away.

  • Thats totally them! You dont know how many hours I spent looking for them! Thanks! As far as supporting them from pulling away, you are right. However, both those SImpson products have a hole in the bottom that I can put another lag or bolt though the bracket up into the knee brace, which should help alleviate that problem. strongtie.com/products/connectors/HDB-HD.asp
    – mohlsen
    May 12, 2015 at 11:13

Another option is a USP Structural Connector - model TDX5.

these were in-stock locally for $20: http://www.lowes.com/pd_14194-166-TDX5___


I had 8 of the ($90) knee braces made for about $70 total by purchasing the 1/4 inch steel plate from a metal recycler. For that price they cut the pieces, drilled the holes and welded them up.


Part of the problem with not using TABs/GLs in conjunction with the expensive bracket you linked to in your question is that as the tree grows, more and more pressure will get placed on the braces.

This may be fine for a period of years depending on the growth rate of the tree, but there is a chance you'll face structural issues later on as the trunk diameter expands but the elements you've added remain fixed. Not saying your way is inherently wrong since trading off cost for longevity may be what is desired, but calling attention to the longer term drawbacks.

There are some good series from Treehouse Dreamers (i.e. TreeHouses.com / Michael Garnier) and from Nelson Treehouse (i.e. Pete Nelson) on YouTube for free if you wanted to hear more.

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