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!

 

 

 

 

 

 

[Tetrarch]

17 hours ago, Square Feet said:

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.

 

Don't know if that was a deliberate pun or not, but blinds are definitively the most effective, but also the most costly option. Not to keep banging the drum but a south-facing room in full sun is almost unusable. In my previous house we had a south-facing garden and our kitchen diner was out of bounds during the summer. Only by shutting the curtains could you keep the temperature reasonable. After a few years I also had a removeable shade sail over an outside pergola to mitigate the sunlight which worked fairly well

 

My new place has 17sq m of vertical glass and 6m of rooflights. This summer was a challenge despite having full blinds on all the verticals, I actually covered two of the rooflights with some leftover PIR insulation panels to stop the solar gain - this is despite solar-control glass and the main glazing being east-facing

 

From your design, none of your openings are too large, so curtains would be cheaper, but you could consider some external shading as an alternative

Regards

Tet

[JohnMo]

12 hours ago, Gus Potter said:

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.  

 

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!

 

 

 

 

 

 

Seems a lot of complexity and possibly high labour costs, for someone on a tight budget.  I wanted something similar but in the end went Durasol (now Ecobrix), really easy, made from recycled material. It was very cost effective. With service void it gives a wall U value of 0.14.  But you could lime plaster direct and have a fully breathable high mass wall that is airtight, leave out the service for a slightly higher U value.  Add additional external insulation if you need to increase the U value.  

[Square Feet]

54 minutes ago, Tetrarch said:

 

Don't know if that was a deliberate pun or not, but blinds are definitively the most effective, but also the most costly option. Not to keep banging the drum but a south-facing room in full sun is almost unusable. In my previous house we had a south-facing garden and our kitchen diner was out of bounds during the summer. Only by shutting the curtains could you keep the temperature reasonable. After a few years I also had a removeable shade sail over an outside pergola to mitigate the sunlight which worked fairly well

 

My new place has 17sq m of vertical glass and 6m of rooflights. This summer was a challenge despite having full blinds on all the verticals, I actually covered two of the rooflights with some leftover PIR insulation panels to stop the solar gain - this is despite solar-control glass and the main glazing being east-facing

 

From your design, none of your openings are too large, so curtains would be cheaper, but you could consider some external shading as an alternative

Regards

Tet

Yes some sort of solar pergola/brise soleil was what I have been thinking. I will make a separate thread on that though as it will get lost in here.

[-rick-]

22 minutes ago, JohnMo said:

Seems a lot of complexity and possibly high labour costs, for someone on a tight budget.

 

Building a larsson type arrangement is definitely not the cheapest option. An I-joist portal could be constructed for less labour (maybe higher material cost) and preserve the deep walls. Probably needs to be more on the slab vs overhanging it though. Two people + a telehandler could likely stand the portal up in a short period of time with temporary bracing and then you have to board it.

 

Edit: but any time savings from doing that might be wiped out if you have to do complex details around big windows.

Edited 8 hours ago by -rick-

[Square Feet]

19 minutes ago, -rick- said:

 

Building a larsson type arrangement is definitely not the cheapest option. An I-joist portal could be constructed for less labour (maybe higher material cost) and preserve the deep walls. Probably needs to be more on the slab vs overhanging it though. Two people + a telehandler could likely stand the portal up in a short period of time with temporary bracing and then you have to board it.

 

Edit: but any time savings from doing that might be wiped out if you have to do complex details around big windows.

Of the famous 'pick 2 of 3' I would go for cheaper and better before quicker. 

My funding isn't all in place and there will be a significant gap between the tranche that will fund the wind-and-watertight shell and the tranche that will fund the interior fitout. So taking longer to get things right and save money isn't a huge problem.

[-rick-]

1 minute ago, Square Feet said:

Of the famous 'pick 2 of 3' I would go for cheaper and better before quicker. 

My funding isn't all in place and there will be a significant gap between the tranche that will fund the wind-and-watertight shell and the tranche that will fund the interior fitout. So taking longer to get things right and save money isn't a huge problem.

 

Agree, though if you are paying for help in any form, then quicker is usually cheaper too. Simpler also = quicker.

 

In terms of performance I expect you can get exactly the same performance from either option.

 

I think it would be very difficult to build any wooden structure solo. Two pairs of hands minimum, so either there are two of your with a fairly unlimited time budget or you are paying for help/asking for favours (which have a limit). Then having a simpler structure that can go up quickly is a huge benefit.

 

Building out of ICF as John suggests is much slower but a lot of it could be done single handed with only lintels, etc, needing a second pair of hands. But then you have to do the roof. Portal style, you build each frame on the ground then stand it up (and brace it). Repeat. Then you board. Single storey makes things a lot easier.

 

One point with the portal style is that I have a feeling (but not at all sure) that you would be able to avoid the need for a big long beam along the ridge of the roof to hold the roof up as each frame section can be self supporting. You just need to brace them against movement. This could be a large cost saving (big glulams are not cheap or easy to install)

 

This really isn't an area I can say much more about. Gus is the expert. However, my main concern from this thread is that finances are really so extremely tight that all decisions really need to be made on a cost first, performance second basis. Not saying you can't get a high performance shell, but a lot of the conventional approaches to achieving that don't really consider cost as a primary factor.

[Square Feet]

I am hoping to build a lot of the panels/frames of the structure myself in an onsite shelter of some sort and then pay people to help me erect it. Hopefully that will mitigate the issue of paying more in wages if it takes longer. 

I don't earn much more than minimum wage and in the gig economy that is further reduced by not getting sick pay, holiday pay etc. It's more cost-effective for me to build as much of this as I am able rather than work my job for the equivalent of something like a tenner an hour to pay someone hundreds a day. Gus is going to design it with that in mind.

[JohnMo]

Just to give you a sense of scale, our walls are 70m long and extend to 3.5m tall at the front of the house and 2.4m at the rear. Front is quite complex with many direction changes. The walls finished took me 4 weeks to build with a assistant helping me. That is fully built and insulated ready for the roof, windows and doors to be fitted working in NE Scotland in December. Total cost worked out at the time was £7500 from memory in 2020, including paying for the assistant.

[Gone West]

2 hours ago, -rick- said:

Two people + a telehandler could likely stand the portal up in a short period of time with temporary bracing and then you have to board it.

Ours started off like that, then the infill frames were craned in. IIRC the SE said the limitations of this system is that the roof angles can't be shallow.

 

[-rick-]

41 minutes ago, Gone West said:

Ours started off like that, then the infill frames were craned in. IIRC the SE said the limitations of this system is that the roof angles can't be shallow.

 

Infill frames around where windows are? A requirement that could be designed out with some thought.

 

I think I've seen (online) something done whereby you build every frame the same, stand them, brace them (even board them). Then come back and infill support structures around windows (cutting the required i-joists then adding lintel support in one operation). Do it that way and you get a protected shell in very short order and then cut in access. But it might be my memory confusing this for something else.

[Nestor]

3 hours ago, Square Feet said:

I am hoping to build a lot of the panels/frames of the structure myself in an onsite shelter of some sort and then pay people to help me erect it. Hopefully that will mitigate the issue of paying more in wages if it takes longer. 

I don't earn much more than minimum wage and in the gig economy that is further reduced by not getting sick pay, holiday pay etc. It's more cost-effective for me to build as much of this as I am able rather than work my job for the equivalent of something like a tenner an hour to pay someone hundreds a day. Gus is going to design it with that in mind.

I like this approach and for me a most enjoyable part of the build. Myself and help from my Dad, 75 years old stick built my self build. This is half of it. 

[Gone West]

2 hours ago, -rick- said:

Infill frames around where windows are?

I didn't explain myself very well. They put up the end frames and a couple of frames in the middle using muscle, braced them, and then used a crane to drop in the intermediate frames. We had some dormers, so some of the frames were odd shapes.