Critique my floorplan please

[Square Feet]

22 hours ago, ETC said:

https://www.dualchas.com/our-journal/dualchas-video

Thanks for this. There's lots I really like about Neil's own house (and some that I don't 😂).

I'm not surprised to hear that they are associated with Mary Arnold Foster as their designs have a similar feel. 

I really love what they are doing and the new approach to Highland architecture. I'm hoping it will work just as well here in the south of Scotland.

[Tetrarch]

One consideration will be some kind of shading. I know you're in Scotland but you will have have massive solar gain for most of the day

 

Also the TV may have glare problems during the afternoon, so it may be mechanical shading required rather than just photo-resistant glazing

 

Regards

Tet 

[JohnMo]

12 minutes ago, Tetrarch said:

One consideration will be some kind of shading. I know you're in Scotland but you will have have massive solar gain for most of the day

Don't underestimate solar gain, it can be painful even in northern Scotland. Consider the less obvious westerly setting sun as much as the southern. 

[Square Feet]

Yes it bothers me alright. I have been thinking, but I haven't come up with an effective solution yet. I'm not blind to the issue though.

[Gus Potter]

On 05/10/2026 at 16:52, Gone West said:

I've never heard of my type of house construction being called space frame. I always called it a timber I-beam portal frame. IIRC the idea was later used by a company called PH15. A space frame to me is the type of frame used in old, light weight, racing car construction, but I could easily be wrong.

You absolutely technically correct about the space frame! I'll try and reason out my thoughts.  I do like your example of the racing car, same applies to certain types of boat construction.. solid timber, ply and plenty glue.  

 

On 05/10/2026 at 17:01, -rick- said:

I'm more familiar with it being a version of a portal frame too. But it both came to mind and your images came up in response to searching 'space frame buildhub'. I could easily be wrong about what @Gus Potter is thinking of here. In any case, I can see your type of build being a good way to build something like this (with the exception of the big windows on the long wall being a difficulty)

You also not wrong and again technically correct. 

 

For a bit of context. I was delighted to be invited by @Square Feet to get involved right at the early planning stage of this project. My brief is roughly be the SE. 

 

@Square Feet Now referred to as SQ. The brief is fabric first, high levels of thermal performance, eco friendly all on a very tight budget. The house has to be elegant, play to the outstanding views, be functional for example. The budget does not easily allow us to just make the house bigger to solve design issues!

 

Now lots of the materials we are thinking about using are for example hemp, wool based products and internal lime plaster. We need to take cognisance of the fact that some of these don't have the best fire ratings for example. The walls are going to be thick and that introduces structural issues around bracing the building against sideways sway under wind loading. We also have to be very careful to avoid condensation within the walls, could be a disaster if we don't set this up right. 

 

SQ and I have had a fair bit of correspondence initially. Then we had a preliminary design meeting for a day, just to meet face to face is very important. Our last meeting was structured so that it included me giving a one to two hour introduction to the basic structural design concepts, call that a "structures lecture". The objective is to allow SQ to see, follow and appreciate the types of things we need to do structurally so we can actually marry up the insulation etc with a structure that is not going to fall down, crack or protest later. 

 

The walls are going to be thick. If we want to use say Hemp and achieve as close as we can to passive house standards. The easiest way for me to describe this to SQ was to call it a space frame. It's not entirely correct, technically,  but it's probably the easiest way to explain some of the basic concepts to a first time self builder. If I do this it means they have a basic understanding of SE stuff and this enables them to make better informed decisions. It removes some of the uncertainty that self builders encounter, gives them confidence. 

 

The house is going to rest on some ground that may have problems. I've plumped for a ground bearing slab at the moment. The slab is thicker than what you may often see. But on balance I feel it will allow me to reinforce locally without complex thickening at the edges or internally where I have point loads. While we use more concrete on the face of it, it makes it more buildable, easier to set out and arguably more carbon efficient, just due to the simplicity.  

 

The house is not heavy, single story. The design is very early stage. But I knocked up the detail below, just to explore for myself, not least, how I would fit all the materials together that SQ wants to use. CAUTION! The detail below is a concept to promote discussion, I know it will have flaws in it so do not copy!

 

 

To explain the above. The inner timbers are vertical load bearing (the roof load). The outer timbers carry the vertical load from the cladding. The cladding vertical load is transferred back to the slab edge as the ply gussets are glue with a structural glue. 

 

The inner timbers are clad with structural ply, to resist the in plane wind loads (looking into the page). The glued ply gussets are rigid moment connections, unlike a standard truss used as a wall element.  The sheet of more breathable ply on the outside also acts as a stiffening element, but if push comes to shove the ply can act compositely with the vertical timbers. 

 

The ply plates turn the wall element into a compound element so the wind suction and internal pressure loads get shared by the inner and outer timbers, then if I need to I can also increase the effective area of the timbers by utilising the ply, the ply turns the timbers into a structural Tee member.

 

But in summary, yes it's not a true space frame, but close. We might say it's a version of the Larsen truss concept.. not really. Most familiar to folk will be the concept of using Posi joists as the vertical wall element or a flat timber truss, like on a flat roof, but as a wall element. But we only have the slab edge so we need to be a bit more crafty. 

 

To summarise. Technically you are all correct.  I've used loose language. Once SQ and I get into the detailed design then we can come up with a name for this kind of bespoke construction that takes into account the types of materials we want to use and their nuances.  

 

But to finish I can tell you all, both SQ and I very much appreciate all your comments, every day is a school day!