Timber Framers Guild Forums General General Forum Questions tension braces

Why is it that so few of the frames that I see being designed and built today do not utilize tension braces(joining the post to the sill plate). They seemingly add a great deal of rigidity to a frame due to their greater size and length compared to knee braces. It seems at least an intelligent decision to use them on end wall bents where they wont get in the way of architecting or is there a good reason to avoid them in frame design????? tb

When designing a frame you have to take all things into consideration.
Window and door placement will sometime help to pick and choose what braces are used and where they are used.

Here is one example:



How is this window going to be trimmed?

Here is another:



Layout your floor plan, including locations of door and windows, then work on elevation drawing showing where the windows will fall in the broad walls or gable walls. What size are the windows?

Once these locations and sizes are known you can compare the frame design to the window locations and see if they will fit.

In both of the above pictures, how are you going to hang window shades or curtains?
These things have to be thought of or the wife won't be happy, with a window in the bedroom that can't have a shade or curtain on it.....

Then you can see if an sill to post brace can be used or not..... and how long it can be....

Jim Rogers

From what I have observed that type of brace (post to sill in corners)is common in traditional english frames its often curved. You see it also in Normandy france where they have 2 or 3 (echarpes) paralel to each other so it becomes a distinctive visual design element in the corner of the frame as well as structuaral. The german ones (streben??)do go from sill to plate I think there is a picture in the historic timber frame tfg book?
Cheers Jonathan

Yes Derek, I meant the so called tension braces that go from the upper third of the post to the sill plate. They are just as futile in tension as knee brace so perhaps the timber framing community needs to come up with a new name. Do you really not peg any of your braces, even your main tie beam -post knee braces? As far as windows and doors getting in between the frame's strength and its architecture, I would much rather sacrifice the window placement in exchange for a more dominating frame, cant we find another place to put a window with these wonderful spatious timber frames we build. Besides I think people are a little window crazy these days ,many people having almost complete walls of windows(kind of excessive). That is just my opinion though and we all know how useless they often are. tb

In the old English book on timber framing a brace that goes from plate or upper timber to post is called a hanging brace.
A brace that goes from sill to post is called a standing brace.
A brace that goes from horizontal timber to horizontal timber, in a corner for example is called a lodging brace.

Examples of braces in a new MA barn:

This could be called a "hanging brace":



This could be called a "standing brace":



This could be called a "lodging brace":



This is truly a "knee brace":



Jim Rogers

I'll ask my German timber framing friend what they are called when he gets back from Germany next week.

Jim Rogers

Derek, I am just curious what type of infill do you use for your frames and how has it proven itself over time here in the more variable climates of diverse America??? tb

Hi Derek
in reality does it really matter what you call it?
cross cultural terminoligy gets complex and confusing

I got some photos of real laerge knee braces, some of these are about 10 foot long.







I saw some knee braces day before yesterday they were about 2 foot either end, on an 1750/1795 forge/wheelwrights building. They were bolted up to the tie bam, and across to the post. No jowl post, no teasle mortise and tennon (possibly stub ones to locate for the bolts) still had the tie beam dovetail into the wall plate though.

Those standing braces on olde englyshe fraymes are usualy heftier than Jims example and enter the post about 2/3 the way up.
Cheers Jonathan

PS Derek do you have any idea who built that barn in your pictures? Were they german/french/swedish/scotish/polish decsent or whatever? Those "standing braces" do seem to be on the extreme side. Are there similar ones nearby?

Heres a photo of a pair of standing braces in a restored suffolk shed (garage) built about 1750 possibly earlier. I dont recall exactly how they were fixed in looks like peged barefaced tenon rather than 20d spikes. I also dont recall the arrangement where the brace is crossed by the girt wether its 1/2 lapped or what? What does 20d mean? This restoation was not my work BTW