Although schooled as an engineer, I don't see myself ever producing a detailed frame design along with structural calculations and joinery details. But when planning a timber frame home, some basic frame layout is part of the floor plan process.

I'm planning a small (1,800 sf +/-) timber frame home and the schematic design consists of three ‘boxes;’ a central entry core with a small wing to one side and a larger wing on the opposite side. To make it easier to visualize, just consider a small square with a rectangle on either side.

When laying out a preliminary framing plan (simple grid), I treated the three boxes separately; but moving forward it seems wrong to have columns immediately adjacent to one another. (the corner columns from two of the ‘boxes’)

Question – is there any reason or situation where it would make sense to maintain the three boxes as separate structural systems? (for a novice, it is much easier to consider each box separately) Or would a real frame designer eventually remove the adjacent columns and design the overall framing plan as a single structure, not three separate boxes?

Ordinarily, treat the whole structure as a complete structure, unless you want to do some sort of a double, banded post and beam system, which would be really interesting to see, but maybe not the traditional look you might be referencing.

For your first timber frame, especially if you are using as is or hewn material, I would recommend working off of centerlines for all of your layout, and try to have all of your components relate to each other in some way. All layouts in the house divisible by 18", for example, also provides a nice framework within which to design. If there is a mathematical underpinning logic to your design, then mistakes in the field are minimized because you have set up an early warning system for your spidy sense, if you know what I mean. If you are used to seeing nothing but 15's and 30's and 36's and suddenly you are getting measurements of 28's and 32's, you instantly know that something is not right.

Of course, the details of the design will be driven by your available materials, so, sometimes, the 3 box system might be the way to go. If none of your timbers are big enough to deal with the loads, and you are going to have to laminate anyway, then individual boxes start looking viable. And, if you already have a mish mash of material, then maybe you can't even utilize a nice clean mathematical grid either, but that might be a 2nd or 3rd timber frame project, instead of a 1st.

Cheers, Chuck

Work on the frame and the house layout / use at the same time. I disagree with Chuck on setting up a grid and blindly using that to design a frame. Yes, there are efficiencies to be gained by running everything on 4x8 sheets, or 32" modules, or 3 apples, whatever - but to me - overtly grid houses don't make good homes. Let your use and traffic patterns and feeling of each space help drive the design.

For your question - it may make sense to build 3 small frames - and in the end they may look like 3 small frames but be connected through walls to stiffen up the entire structure. Nothing like buttressing a core against its wings.

As to adjoining columns - are there walls between? Do the rooms feel balanced with the posts in both rooms? Do you see from 1 room to the other and does it bother you that the posts might be redundant? Do you want to sit or walk through a space and have it feel 'complete' and balanced? Much is in the eye of the beholder... and proportion, use, traffic flow, ceiling heights, and piece size can be variables that make or break a specific design.


And - for corner or 'redundant' posts - often where a small wing abuts a larger wind - I'll size a corner post to be 2"+ larger in 1 direction (so 8x10 or 8x12 or 10x12 etc.) and push that rectangular shape to cover the transition / corner between 2 spaces. Nothing like having the corner of a post touch the corner of your plaster / drywall / wood sheathing and have that post shrink away a bit so you'll forever be looking at a small air space between wall and post...


I think Frank Lloyd Wright said "A doctor can bury his mistakes but an architect can only advise his clients to plant vines."

Change that to "A doctor can bury his mistakes but a timber framer can only advise his clients to hang some cove molding (and blame the architect).

thanks to both for your replies. I'm somewhere in between the two extremes; my compulsive side does start off every plan based on a 4ft by 4ft grid and I manage to keep the framing plan and almost all partitions to that grid. But as soon as doors / windows or bathroom fixtures and kitchen cabinets become involved, the grid becomes mostly pointless. I'll be happy if I can just keep all foundation walls, and framing layout on the grid and let the architectural details fall where they may.

RE: my original question - I must have been dreaming. While it is certainly much easier to plan 3 independent boxes; there is no way that I could justify actually building the home that way. Assuming I move forward with this plan, I will just take it as far as I can (detailed floor plan , schematic frame layout) and then hand it off to a real frame designer to integrate the 3 boxes into a unified whole.