If you could design your Timber Frame so that all of the internal walls were none load bearing, in theory you could remove all of them and just leave yourself with a large open floor space!

In practice, very few people would want to have a full floor area made up of one large open space. - We DO generally tend to split our floor areas up into a number of rooms.  - However, what I am talking about here is the "theory". - If you get the idea of what I am going to be saying, you may be able to use the ideas to make your "design and build" process easier, quicker and cheaper.

Due to the fact that standard floor joists can only be used for limited "spans" (up to around 5m), the way we tend to design houses is to have at least one or two load bearing walls on the ground floor. - That way joists can span "load bearing wall to load bearing wall" across any width of house.

The difference between timber frame and traditional build is that, if you use blockwork for your internal walls, then, whether you want them to be or not, all of your ground floor walls are at least "theoretically" load bearing. – They will normally have foundations underneath them (or at least a slab thickening) and they will be capable of carrying substantial “superimposed” loads (i.e. the weight of the first floor and al the furniture etc). – Because of this ability to carry the loads, Architects and Designers tend to use shorter joist lengths and run joists between load bearing walls. – Once the designer has drawn these shorter joists, and the house is built, then making any changes to the floor layout in the future is made much more difficult.

Use Steel or "glue laminate" beams.

(Note: glue laminate beams are timber beams made up of strips of timber which are glued together which create a beam which is stronger and able to span greater distances than a standard floor joist)

Imagine a rectangular house, say 15 m frontage and 5 m deep. You can easily divide the 15m up into three sections by using 2 steel / glue lam beams running “front to back”, sitting on the front and rear external walls.

These beams could actually, in theory take the place of your load bearing walls. – One set of joists would span between the end wall and the first beam, another between the two beams, and the third would run from the second beam to the other end wall. 

Using this method, joists would usually sit and be securely fitted onto the “flanges” of the steel beams, or be set in joist hanger from glue lam beams.

All the weight of the upstairs floors and furniture would pass through these joists and beams, onto the external walls and down to the foundations.

If you design your floor layout using this technique, you will not only  gain the maximum long term flexibility of the floor plan, but you will also remove the need to have foundations under any internal wall. – This could save you literally thousands of pounds on the cost of your project. - You could then either use the whole area as one wide open floor space, or divide it up as you wish. 

Theoretically, if you didn’t like a particular room layout, you could just strip all the internal walls out and start again!!

If you tried to get the same flexibility from a “Traditional Build” floor plan design you would usually find it very hard to do. – Traditionally built houses tend to have foundations and solid downstairs walls, then, often the upstairs walls are timber stud. – Using blocks of bricks on the ground floor makes it a much harder job to get any flexibility when it comes to making any changes in the future to the layout.

Moving up a floor to the first floor layout:

To get the same “open space” flexibility on the first floor, you need to think about the roof structure.

If you use a standard roof truss structure, and say, we are still use the 15m wide by 5m deep house design mentioned earlier, the normal way for your roof trusses to span would be front to back, (giving you 2 gables at either end of the building).

The trusses, spanning front to back create the same effect at the steel beam and joists on the lower floor. – In other words, they allow you to create a completely open and flexible space to create a floor plan design of your choice. – You can then position your walls in pretty much any position you want. - This is why many traditionally built houses have block walls downstairs and timber "stud" walls upstairs. - The trusses give the builder the chance to build quicker, get a more flexible layout and save money.

If the span from front to back is too great for a standard roof truss to span, you can consider placing a supporting wall running somewhere along the centre of the floor area, from left to right (to cut down the length of the span).

Creating an open floor area on the first floor is actually just as easy to achieve in either Traditional or Timber Frame projects. - But by opting for a Timber Frame, the design process is made simpler and quicker:

1) You dont have to worry about foundations or slab thickenings.  Apart from (possibly) one or two load bearing walls,

2) You can just draw all you internal walls where you want them, then, if you change your mind, you can just rub them out and re position them.

3) You don't need to make as many calculations ffor Building Regulations for foundations (because there are fewer foundations!)

4) You save time and money by not having to dig and pour as many foundations

5) There is less chance of having a long term settlement problem with a poorly constructed foundation

In other words, using timber frame makes the floor plan design process for the ground floor and first floor more flexible, simpler and quicker (and therefore also possibly cheaper). - PLUS it gives you the potential to make a lot of other savings of time and money during the project and gives you less chances of problems later.  

And moving up to the loft / attic:

Attic trusses are basically “beefed up” standard trusses with a “hole in the middle” (instead of lots of timber struts).

When they are all set along the length of a building they create a “corridor” shaped space which can then be spilt down into rooms. – This either allows you to use the attic space immediately as part of the “habitable” part of the house, or to easily change the space from “attic” to “rooms” in the future.

A couple of things to bear in mind when you include attic trusses in your design:

1) Although they are stronger than standard trusses, they still have limited spans. – They can span quite significant open spaces (9m plus), but if they exceed their design limits, then, to be able to use them, you may need to provide support from underneath, part the way across the span. –  In a timber frame project, this would normally be in the form of a supporting "structural timber stud"wall.

This is where the “timber frame versus traditional build” aspect of the build would come into play. – If you build traditionally, you would tend to build that supporting wall in block or brickwork up through both the ground and first floors.

Building a brick or blockwork wall is easier on the ground floor than it is in the first floor. - It is usually more labour intensive on the first floor (getting the materials to the correct place). - It is therefore more expensive and takes longer.

Once you have built a brick or block wall on the first floor, you will also restrict you possible future redesign options because you will always have to take into account "that damn solid wall that’s holding up the roof”!

If you find that, due to the length of the span, you DO need a supporting wall for the attic trusses, then by building the whole structure as a timber frame, it can present a far smaller problem:

a) In actually building it: The panels will come up the same way as the normal panels, they will just be heavier and more substantial.

b) If you want to change the layout in the future: You can usually quite easily make some "structural" alterations to the "structural" panels. – Taking some studs out and adding strengthening studs back in (note: make sure planning and building regs are ok with whatever you do).

2) It is worth giving thought in your initially planning, to what your possible attic conversion could be used for in the future. – If you could one day possibly think of creating a couple of bedrooms and a bathroom from the space, you may need to remove some of the existing attic trusses, which will weaken the structure as a whole. - It may be worth you thinking about adding extra "strengthening" trusses in the locations where you could possibly want openings in the future (see your designer about this). - adding extra attic trusses now wont cost much (about £100 each plus labour) but may save you thousands of pounds later.

There are some things that you will have to consider when designing your floor plan (whether you use timber frame or traditional construction), which will restrict the “future flexibility” of your layout that are nothing to do with the structure itself: