Orkney long house - concept drawings

[westbound]

2 hours ago, Iceverge said:

 

For our interest assign a nominal U value of say 0.15w/m²K per m² to the wall floor and roof of both designs and have a look at how much heat you loose in each design on a 5 deg day for both designs and post is the results. 

 

 

Of course...

 

So comparing our two fancier concepts (full height living space, wasteful 18m x 9m footprint, "big box" concept versus the coupled long house "bungalows"), using round numbers...

 

18 x 9m big box has (18 + 18 + 9 +9) linear metres of wall, 54 LM.

 

Coupled long house "bungalows" have roughly (14 + 14 + (4 x 5.5) + 10 + 10 + 4 + 4) linear metres of wall, 78 LM.

 

Assuming all walls were same height, "bungalows" concept is 45% more surface area/heat loss through walls, compared to big box...before getting to increased roof area.

 

Coupled bungalows could probably get away with lower walls (gabled roof at 45° for height inside), say 1.6m high externally vs 2.4m high (numbers based on round multiples of 400mm high ICF blocks).

 

54 LM x 2.4 m = 130 m2 of external wall in big box

78 LM x 1.6 m = 125 m2 of external wall in bungalows

 

Potentially about the same loss through walls between the two fancier concepts, assuming lower walls on bungalow and relying on high ceilings from gabled roof to keep the internals feeling spacious. 

 

Our smaller box concept is 14.5 x 8.5 m, and assuming it's same height as big box, is about 110 m2 of external walls, beating both of the others by ~20% (round numbers!) through walls.

 

Bungalows have roughly 180 m2 of roof, versus 160 m2 for big box and 125 m2 for small box, quite a big difference there, although U should be better (not by a lot though).

 

From a 5 metres rafter perspective, at 45° roof, don't want the width of a room to be larger than 7 metres.

 

Concrete needed for the 3 concepts:

 

(linear metres x height x ICF core width)

 

Big box = 54 LM x 2.4 m x 0.318 = 43 m3

Bungalows = 78 x 1.6 x 0.318 = 40 m3

Small box = 35 m3

 

Trench foundations at £300 per LM (guesstimate) mean bungalows would be £10k more than small box, internal walls ignored.

 

@Iceverge you've been really helpful at pointing a newbie to some good questions and context...sincerely, thank you!

 

 

 

 

 

Edited Friday at 11:12 by westbound

[Alan Ambrose]

Although the 'bungalows' option is less heat efficient, it does have the bonus of being an interesting design, and it does have the added bonus of being on one level - and for our demographically aging population, that's desirable.

 

So, I think it's good. Else we'll all end up in cubes with a bit of ornamentation on for effect.

 

 

[westbound]

The ICF blocks have an R-value of 30 (0.03 W / m²K) so we're aiming to go pretty strong on that side. Another advantage is that the only neighbour is directly to south (about 30 metres away) so the slightly dog-legged arrangement gives us and then privacy from the living area (which would be the largest spans of glass). Will see, exploring the big, sensible and bungalow designs with a surveyor next week.

[ProDave]

The coupled long houses thing is a local vernacular on Orkney.  At the time I questioned @Stones on his design and his reasoning for doing so was sound, and he has ended up with an efficient house built to that principle.

[westbound]

1 hour ago, ProDave said:

The coupled long houses thing is a local vernacular on Orkney.  At the time I questioned @Stones on his design and his reasoning for doing so was sound, and he has ended up with an efficient house built to that principle.

 

I read that blog about two months ago and wonder if that's where the idea came from 😂

[Iceverge]

12 hours ago, westbound said:

 

Of course...

 

So comparing our two fancier concepts (full height living space, wasteful 18m x 9m footprint, "big box" concept versus the coupled long house "bungalows"), using round numbers...

 

18 x 9m big box has (18 + 18 + 9 +9) linear metres of wall, 54 LM.

 

Coupled long house "bungalows" have roughly (14 + 14 + (4 x 5.5) + 10 + 10 + 4 + 4) linear metres of wall, 78 LM.

 

Assuming all walls were same height, "bungalows" concept is 45% more surface area/heat loss through walls, compared to big box...before getting to increased roof area.

 

Coupled bungalows could probably get away with lower walls (gabled roof at 45° for height inside), say 1.6m high externally vs 2.4m high (numbers based on round multiples of 400mm high ICF blocks).

 

54 LM x 2.4 m = 130 m2 of external wall in big box

78 LM x 1.6 m = 125 m2 of external wall in bungalows

 

Potentially about the same loss through walls between the two fancier concepts, assuming lower walls on bungalow and relying on high ceilings from gabled roof to keep the internals feeling spacious. 

 

Our smaller box concept is 14.5 x 8.5 m, and assuming it's same height as big box, is about 110 m2 of external walls, beating both of the others by ~20% (round numbers!) through walls.

 

Bungalows have roughly 180 m2 of roof, versus 160 m2 for big box and 125 m2 for small box, quite a big difference there, although U should be better (not by a lot though).

 

From a 5 metres rafter perspective, at 45° roof, don't want the width of a room to be larger than 7 metres.

 

Concrete needed for the 3 concepts:

 

(linear metres x height x ICF core width)

 

Big box = 54 LM x 2.4 m x 0.318 = 43 m3

Bungalows = 78 x 1.6 x 0.318 = 40 m3

Small box = 35 m3

 

Trench foundations at £300 per LM (guesstimate) mean bungalows would be £10k more than small box, internal walls ignored.

 

@Iceverge you've been really helpful at pointing a newbie to some good questions and context...sincerely, thank you!

 

 

 

 

 

 

 

I think you need to compare apples to apples. I did a rough calculation with the same floor areas and U values of 0.13 for the walls/floors/ceilings and 1.0 for the 40m2 of windows. 

 

The 221 m2 floor area (excluding the eves)  "Big Box" came out at 553m2 external area + 40m2 of windows and a peak heat loss of 2240W.

 

Adjusting the other design to 221m2 floor area it was 819m2 of external area with 40m2 of windows and a peak heat loss of 2900W. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited Friday at 23:40 by Iceverge

[Iceverge]

12 hours ago, westbound said:

From a 5 metres rafter perspective, at 45° roof, don't want the width of a room to be larger than 7 metres.

As I understand this its the horizontal distance so you could have a 10m wide house (2x5m) with 7 meter (ish) long rafters.