(very long, sorry.....)

The biggest argument against ceiling heights other than 8ft in stick built houses is that 8ft is standard and anything different causes problems (from material ordering to framing 'standard practices.')

In the timber frame world, almost nothing is considered 'standard' so any arguments against other ceiling heights would need to be based on actual problems, not just because its different.

For a conventional timber frame home (if there is such a thing), is there any 'break-point' where increased floor to floor heights begin to cause problems? Obviously, 8'6" should not call for a drastically different frame design compared to an 8ft ceiling. But is there some point where the typical frame design, bracing details, etc. become invalid and a whole different approach needs to be taken?

Preliminary plans are based around a one and one-half story structure. (is that the correct term when there is a second story over half of the building footprint, but the other half is only a single floor?)

I've read a few opinion pieces against the common 'great room' concept with its double height ceiling. I agreed with the author's premise that I'm building a home, not a church and that the benefits of increased ceiling height can be achieved with just a couple of extra feet, not an entire (missing) 2nd floor. Taken to its extreme, you could not alter the basic 8ft floor to floor structure at all; if the great room has no floor above it. Just remove the drywall ceiling over the great room and open up the room to the underside of the pitched roofline.

My idea is in between the two extremes. If the first floor ceiling height (at perimeter walls) was 9'6 or 10', and the great room area was open to the underside of the roofline, that would provide the impact of wide open space without building an 'empty second floor' over half of the house.

Visually, that works for me; but what about structurally? If the entire first floor is now 9'6" or 10' tall, how much of an impact does that have on frame design (and construction) compared to an 8' ceiling? Is it just a matter of ordering longer columns, (and maybe beefier bracing) or does the whole frame design become significantly more complex (and expensive)?

There are some additional side benefits to the raised floor to floor heights, particularly if normal ceiling heights are used in the 2 story section of the house. If the kitchen / guest bath / laundry room / mechanical room section of the first floor has an 8ft ceiling, there would be a very useful space between the first floor ceiling and 2nd floor that could be used for forced air ductwork, and all sorts of other utility routing. The value of this space would offset some of the costs of a taller structure.

This brings me back around to the original question - is an extra two feet of floor to floor framing just a minor incremental change; or does it require a significantly new approach?

Thanks

storey and a half means that the sidewall hieght is approx 12 ft, so at the sidewall you have full ceiling downstairs and half hieght upstairs. doesn't matter how much floor is covered on the second floor.
I would think that as you increase the hieght of the second floor, your downstairs braces would get longer, and i think we are talking in the 1/3 of post length here. for example, a 9 foot cieling would go with a 36/36/50.91 brace.

It's good to have some of the main floor open to the second floor, I prefer to get that open area in conjuction with the staircase/chimney rather than leave half the second floor open to below.

Hi Toluca and Mark,

This is a dissertation topic !

Very few vernacular buildings have any form of bracing found on the ground (1st) floor with these components generally being found on the upper (2nd) floor. A sure giveaway sign of an old building is the height of the wall plate which tends to be driven by available post height with this lying somewhere between 10 and 12 feet. The mid (girding) rail is just that - it tends to be set half way between u/s ground sill and t/o wall plate with upper floor joists sitting on top of that rail thereby resulting in quite low headroom on the ground floor (typically 7 ft) with a disproportionately high upper headroom of about 10 ft to underside of collars.

As with everything in life one occasionaly comes across a building that turns everything upside down and this is the case at The Olde Bell in Henley on Thames, Oxfordshire (dendro dated to 1325) where the lower floor headroom [underside sill to top of floor] is 8 ft with an upper floor headroom [top of floor to to top of wall plate] being 10 ft above which soars an open crown post roof.

Good question !

Regards

Ken Hume

toluca

Your question seems to directed mainly at the timber frame design itself. While there may or may not be impacts of floor to floor height on the timber frame, here a couple other things to consider for the project as a whole (which maybe you already have, in which case feel free to just ignore this).

How are you going to enclose the frame? If you are thinking of a conventional stud wall construction, then you will still have to deal with the standard lengths of 2x material as well as the standard sheet size for whatever sheathing you intend to use. If not a stud wall, then what are standard dimension for the material you do intend to use? Not everything has a standard size and maybe you can avoid them, it seems the majority of them do in the construction industry.

Will the interior walls go to the underside of the floor above? Will those consist of stud framing and drywall? Again, those have standard sizes to deal with and may mean more cutting and more waste.

How will the additional 2 feet of height impact the budget? The longer posts may not be much expense, but you will have 2 more feet of exterior wall construction, siding, interior wall construction, wall finishes… That can all add up in a hurry.

Do you have room for the additional stairs it will take to get up the extra 2 feet to the second floor?

I think the whole 2 story tall great room space is a personal preference. Some people like it, some don’t. It will make the home more expensive for the square footage you get. With that 2 story space, you are paying to build most of the house without getting that second floor space to use. If you like the big vaulted space and can afford it, I say go for it.

Finally, do the proportions of the spaces still work? Depending on the overall size of the house and the design, a 9’-6” to 10’-0” ceiling may be preferable. Does this impact the size of the doors and windows in the space? Does a standard 6’8” high door look odd on a 10’ high wall to you? Does an 8’ high door look better? Do the windows need to be taller to be in proportion with the taller walls? These things will increase the cost. Again, these are things that will all depend on what feels right to you and what works with your budget.


Just a few thoughts. Good luck.