At last, we’re finally ready to put together the design for our house. A fully specified design, with every detail and system described, is well beyond the scope of this newsletter (not to mention the scope of my knowledge). But we can give a high-level schematic design, laying out the basic building systems and how they’ll work together to satisfy our exhaustive design criteria.
I think it would also be interesting to consider the opposite extreme. I visited the North Carolina Outer Banks a few years ago, and noted how transitory the islands and sandbars are compared to the houses and strip malls built on top of them. We usually think of the location a building is built on as a layer that is even more permanent than any of the building layers, but for a place like these barrier islands that naturally move on a timescale of decades or even years, but are still desirable places for people to live in or visit, it would be interesting to think about what construction methods are best for a building with just the right lifespan to be moved or replaced as the island has shifted.
Very thought provoking, thank you. A few thoughts:
- Gutters are a significant source of problems if not cleaned an maintained; instead why not use a design with overhangs and a properly graded and hard-landscaped building perimeter?
- A much cheaper alternative to masonry cladding would be something like fibre cement siding (e.g. HardiePlank); it's resistant to fire, insects, damp, and rot, and requires almost no maintenance. Granted, it's not nearly as attractive as masonry, so the preservation value would be lower, but it's much easier to install and replace as new technologies appear.
- Perhaps I missed it, but you didn't spend much time discussing the other elements of exterior walls. It would be worthwhile to consider techniques and materials for all of the layers:
- exterior cladding
- mounting system for cladding
- water / insect barrier
- structural components, usually with insulation
- vapour barrier
- service space
- interior cladding
To make modification easier as technologies and usage change, a "service space" for electrical, plumbing, and other services inside the structural layer (e.g standard softwood studs placed inside the vapour barrier) makes changes much easier and protects the service runs from moisture and temperature changes.
- While I agree that wood burning fireplaces are a good idea for longevity (notwithstanding the climate issues), I would worry about the chimney construction, cap durability, and roof transition design. Debris accumulates around chimneys and can lead to roof failure.
- On that note, a roof height and design that makes access easy would encourage regular maintenance.
Re: eaves vs gutters, I agree, blocked gutters is a major potential failure point. It's a question of what's more likely to occur, gutter blockage causing problems, or the grading/exterior drainage getting messed up and causing problems. My choice was based on a guess of the latter, but this is arguable (especially since drainage problems around the base of the house would arguably be more visible).
I didn't discuss the full wall assembly. I think the majority of these items are very likely to be replaced many times (ten or more) over the house's lifespan (I'm imaginging that basically everything other than the exterior wall, the foundation, and the structural frame will be totally ripped out at various times in the home's life). So our decisions about what they are are less important than making sure we can easily replace them (and that our more permanent elements will work with them). But other folks may draw this line differently (in particular, several commenters have made a pretty good case case that insulation/energy performance needs to be a much more central concern).
Re: fireplace, agree, this probably needs to be rethought a bit.
Paying attention to chimney location can pretty much solve the accumulation of debris.
The end of a gable would be best, though centralizing the heat source is most energy efficient. I'd put it there or just to one side of a ridge beam, where there's 2-4 times the opportunity for leaks, but it's at least out of the way of structure and won't catch debris.
I would caution against choosing the area around London. It is a mild climate now, but climate change has the potential to disrupt the North Atlantic Current (https://en.wikipedia.org/wiki/North_Atlantic_Current) and plunge the British Isles into a northern Canada type climate.
"Unreinforced concrete" in your foundation can mean a lot of things. Modern concrete has very different formulation from ancient concrete, and it matters; for example, modern concrete deteriorates if chloride ions get into it. So if you're going to use concrete, you have to make sure you get the chemistry right, and that probably means you're not going to be using anything you can just order from a random supplier. You need "advanced concrete" in the sense of having real control over the properties.
For that matter, not all reinforcement is corrodable metal. You could put a bunch of fiberglass or something in your foundation concrete, although admittedly future repairs might fail to maintain that.
Why a crawlspace and not a full usable basement? Even when you don't need to get below a frost line (and I do think you'd be a lot better of building somewhere where it doesnt' freeze at all), a basement is nice to have. You're already going to be excavating like crazy anyway.
It seems strange to try to fireproof steel framing with concrete or brick masonry (with bolts through it!) rather than the more traditional gypsum plaster. Plaster is easier to apply, definitely easier to repair, probably less technology-intensive, and actually cools the structure as it calcines in a fire. And you can easily buy gypsum with very well characterized fire resistance in both plaster and panel form today. You could of course then bury the plaster in interior masonry walls if you wanted a thicker layer around it. You could even use firebrick.
I think your brick exterior walls are gonna fall apart. It seems backwards to rule out any and all organic polymers, but then to be willing to rely on having somebody regularly maintaining the wall. Somewhere in your 1000 years, there's almost certainly to be a 100 year period of nearly total neglect. You don't seem to be treating cost as important, so maybe interlocking masonry that would hold together even if it didn't have mortar? Would stone or something be better than brick?
You could stick a superficial insulation layer on the outside of the wall where it belongs. It will fail, and need to be replaced, but you can probably design the wall to be more or less OK with or without the insulation in place. The insulation won't be pretty, but if future people demand pretty, then they can rip the insulation off and use the base wall. You'll meet energy efficiency standards now, and reduce wear and tear for a while, and it may be easier to survive if the power goes out.
If you build the house in an urban area and expect the area to stay urban, where are you going to be getting the wood for those fireplaces? Fireplaces only work as a "collapse of civilization" alternative if you have a large dedicated woodlot. And chimneys have their own problems. Oh, and new fireplaces are ILLEGAL to build in the urban area where I live, and I imagine in others too, and for very good reasons. Can you come up with passive design elements that will keep the building more or less habitable even with no heat at all?
I'm also unsure about urban locations in general; they tend to get redeveloped.
Re: concrete, yep, the super long-lifespan, slow curing mixes are pretty carefully formulated and different than normal concrete. The linked paper goes into some detail on what they used.
Re: plaster vs brick/concrete, I think this is a pretty good suggestion. My thinking on preferring concrete or brick is a vague sense of it being more durable and replaceable than gypsum, but I’m actually not sure that that’s true.
Re: wall durability, my concern about polymers is them failing somewhere that can’t be repaired or even noticed, and that they seem especially susceptible to decay. I agree that accommodating a long period of total neglect is important, I’m just not sure of a better option. I’m reluctant to use something extremely specialized/nonstandard, which would include mortar free masonry. I considered using all stone masonry instead of brick, so I could be convinced this was a better choice.
Re: chimney/fireplace, this is probably true, I’m probably over-indexing it’s usefulness, though I still think a home should have its own heat-generating capability that requires a minimum of support infrastructure. Open to suggestions here.
Re: urban areas, I agree this is a tough needle to thread. But the most important thing for a home to stay in use is it for to be maintained, and for it to be maintained it needs to be somewhere people want to live. Drive around any rural area in the US and you’ll see a long parade of homes that are abandoned and falling apart because no one wants to live there. The same is true for cities, but I think it’s on the whole less of a risk there.
I thought of the open fireplace as well, which many people have brought up. I think the romantic appeal bumps it higher up my list than the valid critiques would have it, and maybe the same's happened in your assessment, Brian.
But the irreducible fact is that through most of the world you're going to need heat for some part of the year, we need heat to cook, and the open hearth has been the most common and flexible heater throughout history all over the world. In a pinch you can heat yourself or food, and do it with whatever fuel you can get to combust. No source of timber? Use peat. Or dung. Or twisted fiber. Or in a truly apocalyptic scenario, scavenge furniture and such from the detritus of the collapsed society around you like post-Roman England did.
But the problems of an open fireplace are real. So how about a wood-burning stove (one that doesn't require specialized fuel like a pellet stove)? For longevity you'd want to stay away from anything complex or proprietary, but a steel or masonry box with a door inside of another steel or masonry box would be very simple to make and repair. With a properly designed baffled flue, combustion should be greater than 75%. That efficiency can be boosted by various more complex add-ons, some of which could be installed in a way that allows them to be replaced or discarded at the end of their life.
Emissions will still be higher than an oil furnace and much higher than a gas furnace, but wood is the ultimate renewable resource when grown and harvested responsibly.
Jan 5, 2022·edited Jan 5, 2022Liked by Brian Potter
I am very skeptical of the exterior wall/insulation choices. Modern living temperatures are substantially higher than those in medieval buildings, leading to increased energy loss and higher water saturation.
Wherever you have a warm, moist living interior and an exterior at freezing temperatures, water will tend to migrate into the exterior. If the walls are porous and the dew layer falls inside your brickwork, that's a very bad situation where freeze and thaw cycles over days and seasons will damage the masonry. Maybe not be substantial in a place like London, where freezing cycles are relatively rare, but a fundamental drawback in many places of the inhabited Northern hemisphere.
The energy consumption of the building cannot be ignored, and past trends, in a Europe or US densely covered in trees, cannot be extrapolated into the future. It's good that we have fireplaces as a fallback, but the building should also have extremely high thermal insulation, close to passive house standards, made of very hardy materials like AAC. If the future will be energy rich, it won't matter, but we don't see that yet.
Maybe try something like the free online tool Ubakus to figure out a better exterior wall choice from both the humidity and energy waste aspects.
I agree the exterior wall design needs some figuring out. My choice was based on a combination of historical performance, and the fact that modern builders designing specifically for durability also use it (I was influenced by the work of John Simpson Architects here), which suggests to me that thick masonry can be made to work. My sense is that if you choose brick with a sufficiently high S_crit you can avoid most freeze/thaw issues. I’m willing to be convinced a different assembly would be better, though I think anything that relies on something polymer-based to maintain the building envelope is probably right out.
I agree energy performance is important, since all else being equal people will prefer a house that’s less expensive to heat/cool (especially in a world where energy is much more expensive), though I would caution not to over-index on it.
Jan 7, 2022·edited Jan 7, 2022Liked by Brian Potter
I was thinking mortared AAC as well, but to use it for the vertical structure as well as enclosure. Your point about decoupling the functional layers is very good in general, but that makes it a good principle to start from, while I think you may have slipped a bit into dogma on it. Buildings that have lasted centuries decouple performance layers (or have had those layers decoupled), but I can't think of any that don't also have a fundamental layer that at least partially fills several roles. Masonry, for instance has usually provided both structure and cladding, as well as often some insulation through mass.
Thick AAC is impervious to decay at much lower cost than using SS, and doesn't require fireproofing. At the scale of a house it will do all the same structural work in a way that's much simpler to understand and not muck up down the line - shear and wind are pretty much built in. Repairs require no specialized masonry skill, and if specialized AAC materials are not available for repairs and modifications any old masonry products will do.
I'm not sure about differential expansion, but assuming that's OK, my favored wall assembly would start with the same double-wythe lime-mortared brick exterior with heares tying the wythes together. Regular rowlocks would tie the rear wythe back to the AAC wall across a 1" air gap for thermal and moisture break. Any AAC reinforcement would be fiberglass.
At 17-21" this would be thick, but also efficient and durable to all forms of damage. It would be very moisture resistant, but could dry to either side as required. It's not even all that thick compared to historical walls, but if differential expansion really isn't an issue, one wythe of brick would work fine.
This is an interesting idea for the wall assembly (is there any good information on expected AAC service life?) But I don't think AAC is a good candidate for the structural frame, the major reason being that you can't really span with AAC - as far as I know, AAC floor panels basically just act as formwork for a layer of reinforced concrete on top (see here, for instance: https://www.aerconaac.com/structural-design.html )
I think the best alternative to using stainless frames would be a concrete frame using stainless or basalt rebar - similar benefits to the steel frame with the added bonus of fire resistance. The main drawbacks are legibility and durability (I foresee the concrete frame accumulating cracks, chips, spalls, and holes over it's lifespan in a way that would be difficult to repair easily), but I'm open to the possibility that you could design it in a way to minimize these problems.
(edit, I see now you intended the AAC to just be vertical support, not horizontal. Possible, though I still think a full-frame system is preferable to a beams-bearing-on-walls system)
I was assuming AAC block because it stands on its own, and as you noted I specified using it for the vertical assembly. You're completely right about spanning, and there's no way I'd use it for that - I don't even like the idea of using AAC horizontally for regular construction! It seems very much to me like the manufacturers of a specific product stretching to say their product can build a whole house, when it's really not good for that.
Legibility is exactly why I think a masonry wall is preferable to a frame because the principles for loads from wind, settling, earthquake, etc. are all inherent to the assembly itself. They're robust, redundant, and obvious to the naked eye. In any frame system, the connections are key. If a couple bolts are compromised, or an angle brace is removed, the whole thing becomes much more susceptible to racking, and the >right< way to fix that might not be obvious to future caretakers.
As much as I love your SS beams, they're tough to attach to, and I can't help myself from considering cost at least somewhat. So what would you think of a hardwood/SS flitch beam?
I think Gypsum is soft enough that it would only serve to structurally decouple the wood from the steel. Once again, though I'm a new tech fan I'd lean on the old ways: big wood to protect the steel. Heavy timber doesn't require the same fireproofing because it doesn't catch the same way as light frame. Fire failure might even be better than just the steel S or W. You were going to have to wrap those with something anyway, because your fire solution of brick doesn't address the horizontals.
Jan 5, 2022·edited Jan 5, 2022Liked by Brian Potter
We should consider the value of the building as a piece of architecture. Design with a great architect and it is very likely that the intrinsic value of the building helps it to make the 1000 years. Imagine Le Corbusier built your house, your house would be preserved indefinitely even if the repairs were costly and materials would need replacement
I agree about the importance of “cultural value” as a mechanism for keeping a building around long-term (I dive into this in part II). But it’s tricky to ensure that this happens - lots of culturally valuable buildings haven’t survived, even buildings by famous architects.
It is March 2024, in about 5 years me and my oldest will be building a small place for him to live. As much as I like this. I will not be in a position to construct this financially . BUT that being said, I read the whole thing instead of sleeping and took me over 45 min to read fully rereading what was necessary to understand it better. I wish I could do this. I ended up here from reading the files of my ancestors in residential school and one of them was asked after graduation to do a questionnaire asking if they are using their education what job they are doing , if they are married and have kids and where they live and do they own their own home and what kind of home is it, he said balloon house so I went to find what one was. And ended up here. I only went to have a smoke an hour and 45 min ago. Now I have been on this page an hour. Thank you for many ideas that some of which I can incorporate
any structure you build large and durable enough is likely to be used as a fortress in times of war.
The only long-lasting constructions are those with continuous use- castles and hostels, sometimes resteraunts and spas. The only reason other buildings have survived is as cultural icons or practically uninhabitable structures.
For these reasons, i will be going with a different approach- short sections of enormous quansit hut arches angled for a sloped roof to allow ventilation and updrafts to reduce moisture, overlaid by concrete, to form several hundred feet wide and 5-8 thousand square feet floorplans, all built into hillsides underground but above flood plains and with clear drainage to the front.
The front of the structure will slightly protrude from the hillside and be sloped, consisting mainly of glass with a stone foundation facing at the bottom where an outwardly sloping base will incorporate drainage along with utility functions. Internally the structure will incorporate several large, thick, fiberglass reinforced (which is not susceptible to corrosion) spacing walls with cutouts for doorways and utility spaces, all of which will be brought together by composite lumber. That way it will not be subject to extended bombardment in an attempt to exterminate the inhabitants and the building if burned out can be rebuilt and repurposed.
Interior design is an intricate process that involves a myriad of considerations, from conceptualization to execution. It begins with thorough research and analysis, where designers explore the client's needs, preferences, and the functional requirements of the space. This stage often involves conducting site visits, surveys, and interviews to gather pertinent information.
This long lifetime building design makes basically no economic sense in worlds where the future turns out to be seriously scifi.
For example.
1) Earth is taken apart to build a dyson sphere.
2) Digital minds running on computers
3) Drexler style nanotech, tiny robots arrange the atoms any way you want.
4) Future giant particle accelerator makes a black hole that destroys earth.
The building might still have historical value in some of these worlds. And if "preservation as a historical curiosity" is something you are aiming for, sure go ahead.
Solar panels are a new construction material, whose energy output offsets its cost, maybe even pay for themselves. Their reinforced tempered glass construction withstands hail beyond what slate can, so even if their output degrades and the occupants choose not to replace them to collect free energy from the sun, they remain a good roofing material. I think photovoltaic panels will remain with our civilization in the centuries ahead like stainless steel or unreinforced concrete, even though more advanced and longer-lasting materials exist. Sized correctly (12lb 100W panels, not the crazy 4’x8’ drywall sized sheets meant for cheap solar farms) they are easily transportable and easy to replace.
Solar panels will power induction cooktops, heat pumps, hot water systems, water purification, and their output can be stored in batteries or shared with a local grid.
Thus you can trade away the chimney and all its structural, drainage, and maintenance headaches. I might suggest an inbuilt roof anchoring system to keep the roof safely serviceable.
just came across this series - fascinating! one way to preserve a building given changing local value is to make the building moveable. We've all seen the pictures of the historic house being moved down the street right? Its seems many of your value concerns over time could be addressed by assuming the building would be moved 2 or 3 times in it's 1000 year life. Your proposed structure over the foundation would lend itself to being more easily moved.
I think it would also be interesting to consider the opposite extreme. I visited the North Carolina Outer Banks a few years ago, and noted how transitory the islands and sandbars are compared to the houses and strip malls built on top of them. We usually think of the location a building is built on as a layer that is even more permanent than any of the building layers, but for a place like these barrier islands that naturally move on a timescale of decades or even years, but are still desirable places for people to live in or visit, it would be interesting to think about what construction methods are best for a building with just the right lifespan to be moved or replaced as the island has shifted.
Very thought provoking, thank you. A few thoughts:
- Gutters are a significant source of problems if not cleaned an maintained; instead why not use a design with overhangs and a properly graded and hard-landscaped building perimeter?
- A much cheaper alternative to masonry cladding would be something like fibre cement siding (e.g. HardiePlank); it's resistant to fire, insects, damp, and rot, and requires almost no maintenance. Granted, it's not nearly as attractive as masonry, so the preservation value would be lower, but it's much easier to install and replace as new technologies appear.
- Perhaps I missed it, but you didn't spend much time discussing the other elements of exterior walls. It would be worthwhile to consider techniques and materials for all of the layers:
- exterior cladding
- mounting system for cladding
- water / insect barrier
- structural components, usually with insulation
- vapour barrier
- service space
- interior cladding
To make modification easier as technologies and usage change, a "service space" for electrical, plumbing, and other services inside the structural layer (e.g standard softwood studs placed inside the vapour barrier) makes changes much easier and protects the service runs from moisture and temperature changes.
- While I agree that wood burning fireplaces are a good idea for longevity (notwithstanding the climate issues), I would worry about the chimney construction, cap durability, and roof transition design. Debris accumulates around chimneys and can lead to roof failure.
- On that note, a roof height and design that makes access easy would encourage regular maintenance.
Thanks again, very interesting!
Re: eaves vs gutters, I agree, blocked gutters is a major potential failure point. It's a question of what's more likely to occur, gutter blockage causing problems, or the grading/exterior drainage getting messed up and causing problems. My choice was based on a guess of the latter, but this is arguable (especially since drainage problems around the base of the house would arguably be more visible).
I didn't discuss the full wall assembly. I think the majority of these items are very likely to be replaced many times (ten or more) over the house's lifespan (I'm imaginging that basically everything other than the exterior wall, the foundation, and the structural frame will be totally ripped out at various times in the home's life). So our decisions about what they are are less important than making sure we can easily replace them (and that our more permanent elements will work with them). But other folks may draw this line differently (in particular, several commenters have made a pretty good case case that insulation/energy performance needs to be a much more central concern).
Re: fireplace, agree, this probably needs to be rethought a bit.
Re: roof height, agreed.
Paying attention to chimney location can pretty much solve the accumulation of debris.
The end of a gable would be best, though centralizing the heat source is most energy efficient. I'd put it there or just to one side of a ridge beam, where there's 2-4 times the opportunity for leaks, but it's at least out of the way of structure and won't catch debris.
I would caution against choosing the area around London. It is a mild climate now, but climate change has the potential to disrupt the North Atlantic Current (https://en.wikipedia.org/wiki/North_Atlantic_Current) and plunge the British Isles into a northern Canada type climate.
I actually thought about this, but decided that figuring out what’s going to happen with the Gulf Stream would be too much effort
"Unreinforced concrete" in your foundation can mean a lot of things. Modern concrete has very different formulation from ancient concrete, and it matters; for example, modern concrete deteriorates if chloride ions get into it. So if you're going to use concrete, you have to make sure you get the chemistry right, and that probably means you're not going to be using anything you can just order from a random supplier. You need "advanced concrete" in the sense of having real control over the properties.
For that matter, not all reinforcement is corrodable metal. You could put a bunch of fiberglass or something in your foundation concrete, although admittedly future repairs might fail to maintain that.
Why a crawlspace and not a full usable basement? Even when you don't need to get below a frost line (and I do think you'd be a lot better of building somewhere where it doesnt' freeze at all), a basement is nice to have. You're already going to be excavating like crazy anyway.
It seems strange to try to fireproof steel framing with concrete or brick masonry (with bolts through it!) rather than the more traditional gypsum plaster. Plaster is easier to apply, definitely easier to repair, probably less technology-intensive, and actually cools the structure as it calcines in a fire. And you can easily buy gypsum with very well characterized fire resistance in both plaster and panel form today. You could of course then bury the plaster in interior masonry walls if you wanted a thicker layer around it. You could even use firebrick.
I think your brick exterior walls are gonna fall apart. It seems backwards to rule out any and all organic polymers, but then to be willing to rely on having somebody regularly maintaining the wall. Somewhere in your 1000 years, there's almost certainly to be a 100 year period of nearly total neglect. You don't seem to be treating cost as important, so maybe interlocking masonry that would hold together even if it didn't have mortar? Would stone or something be better than brick?
You could stick a superficial insulation layer on the outside of the wall where it belongs. It will fail, and need to be replaced, but you can probably design the wall to be more or less OK with or without the insulation in place. The insulation won't be pretty, but if future people demand pretty, then they can rip the insulation off and use the base wall. You'll meet energy efficiency standards now, and reduce wear and tear for a while, and it may be easier to survive if the power goes out.
If you build the house in an urban area and expect the area to stay urban, where are you going to be getting the wood for those fireplaces? Fireplaces only work as a "collapse of civilization" alternative if you have a large dedicated woodlot. And chimneys have their own problems. Oh, and new fireplaces are ILLEGAL to build in the urban area where I live, and I imagine in others too, and for very good reasons. Can you come up with passive design elements that will keep the building more or less habitable even with no heat at all?
I'm also unsure about urban locations in general; they tend to get redeveloped.
Re: concrete, yep, the super long-lifespan, slow curing mixes are pretty carefully formulated and different than normal concrete. The linked paper goes into some detail on what they used.
Re: plaster vs brick/concrete, I think this is a pretty good suggestion. My thinking on preferring concrete or brick is a vague sense of it being more durable and replaceable than gypsum, but I’m actually not sure that that’s true.
Re: wall durability, my concern about polymers is them failing somewhere that can’t be repaired or even noticed, and that they seem especially susceptible to decay. I agree that accommodating a long period of total neglect is important, I’m just not sure of a better option. I’m reluctant to use something extremely specialized/nonstandard, which would include mortar free masonry. I considered using all stone masonry instead of brick, so I could be convinced this was a better choice.
Re: chimney/fireplace, this is probably true, I’m probably over-indexing it’s usefulness, though I still think a home should have its own heat-generating capability that requires a minimum of support infrastructure. Open to suggestions here.
Re: urban areas, I agree this is a tough needle to thread. But the most important thing for a home to stay in use is it for to be maintained, and for it to be maintained it needs to be somewhere people want to live. Drive around any rural area in the US and you’ll see a long parade of homes that are abandoned and falling apart because no one wants to live there. The same is true for cities, but I think it’s on the whole less of a risk there.
I thought of the open fireplace as well, which many people have brought up. I think the romantic appeal bumps it higher up my list than the valid critiques would have it, and maybe the same's happened in your assessment, Brian.
But the irreducible fact is that through most of the world you're going to need heat for some part of the year, we need heat to cook, and the open hearth has been the most common and flexible heater throughout history all over the world. In a pinch you can heat yourself or food, and do it with whatever fuel you can get to combust. No source of timber? Use peat. Or dung. Or twisted fiber. Or in a truly apocalyptic scenario, scavenge furniture and such from the detritus of the collapsed society around you like post-Roman England did.
But the problems of an open fireplace are real. So how about a wood-burning stove (one that doesn't require specialized fuel like a pellet stove)? For longevity you'd want to stay away from anything complex or proprietary, but a steel or masonry box with a door inside of another steel or masonry box would be very simple to make and repair. With a properly designed baffled flue, combustion should be greater than 75%. That efficiency can be boosted by various more complex add-ons, some of which could be installed in a way that allows them to be replaced or discarded at the end of their life.
Emissions will still be higher than an oil furnace and much higher than a gas furnace, but wood is the ultimate renewable resource when grown and harvested responsibly.
This is a good suggestion.
I am very skeptical of the exterior wall/insulation choices. Modern living temperatures are substantially higher than those in medieval buildings, leading to increased energy loss and higher water saturation.
Wherever you have a warm, moist living interior and an exterior at freezing temperatures, water will tend to migrate into the exterior. If the walls are porous and the dew layer falls inside your brickwork, that's a very bad situation where freeze and thaw cycles over days and seasons will damage the masonry. Maybe not be substantial in a place like London, where freezing cycles are relatively rare, but a fundamental drawback in many places of the inhabited Northern hemisphere.
The energy consumption of the building cannot be ignored, and past trends, in a Europe or US densely covered in trees, cannot be extrapolated into the future. It's good that we have fireplaces as a fallback, but the building should also have extremely high thermal insulation, close to passive house standards, made of very hardy materials like AAC. If the future will be energy rich, it won't matter, but we don't see that yet.
Maybe try something like the free online tool Ubakus to figure out a better exterior wall choice from both the humidity and energy waste aspects.
I agree the exterior wall design needs some figuring out. My choice was based on a combination of historical performance, and the fact that modern builders designing specifically for durability also use it (I was influenced by the work of John Simpson Architects here), which suggests to me that thick masonry can be made to work. My sense is that if you choose brick with a sufficiently high S_crit you can avoid most freeze/thaw issues. I’m willing to be convinced a different assembly would be better, though I think anything that relies on something polymer-based to maintain the building envelope is probably right out.
I agree energy performance is important, since all else being equal people will prefer a house that’s less expensive to heat/cool (especially in a world where energy is much more expensive), though I would caution not to over-index on it.
I was thinking mortared AAC as well, but to use it for the vertical structure as well as enclosure. Your point about decoupling the functional layers is very good in general, but that makes it a good principle to start from, while I think you may have slipped a bit into dogma on it. Buildings that have lasted centuries decouple performance layers (or have had those layers decoupled), but I can't think of any that don't also have a fundamental layer that at least partially fills several roles. Masonry, for instance has usually provided both structure and cladding, as well as often some insulation through mass.
Thick AAC is impervious to decay at much lower cost than using SS, and doesn't require fireproofing. At the scale of a house it will do all the same structural work in a way that's much simpler to understand and not muck up down the line - shear and wind are pretty much built in. Repairs require no specialized masonry skill, and if specialized AAC materials are not available for repairs and modifications any old masonry products will do.
I'm not sure about differential expansion, but assuming that's OK, my favored wall assembly would start with the same double-wythe lime-mortared brick exterior with heares tying the wythes together. Regular rowlocks would tie the rear wythe back to the AAC wall across a 1" air gap for thermal and moisture break. Any AAC reinforcement would be fiberglass.
At 17-21" this would be thick, but also efficient and durable to all forms of damage. It would be very moisture resistant, but could dry to either side as required. It's not even all that thick compared to historical walls, but if differential expansion really isn't an issue, one wythe of brick would work fine.
This is an interesting idea for the wall assembly (is there any good information on expected AAC service life?) But I don't think AAC is a good candidate for the structural frame, the major reason being that you can't really span with AAC - as far as I know, AAC floor panels basically just act as formwork for a layer of reinforced concrete on top (see here, for instance: https://www.aerconaac.com/structural-design.html )
I think the best alternative to using stainless frames would be a concrete frame using stainless or basalt rebar - similar benefits to the steel frame with the added bonus of fire resistance. The main drawbacks are legibility and durability (I foresee the concrete frame accumulating cracks, chips, spalls, and holes over it's lifespan in a way that would be difficult to repair easily), but I'm open to the possibility that you could design it in a way to minimize these problems.
(edit, I see now you intended the AAC to just be vertical support, not horizontal. Possible, though I still think a full-frame system is preferable to a beams-bearing-on-walls system)
I was assuming AAC block because it stands on its own, and as you noted I specified using it for the vertical assembly. You're completely right about spanning, and there's no way I'd use it for that - I don't even like the idea of using AAC horizontally for regular construction! It seems very much to me like the manufacturers of a specific product stretching to say their product can build a whole house, when it's really not good for that.
Legibility is exactly why I think a masonry wall is preferable to a frame because the principles for loads from wind, settling, earthquake, etc. are all inherent to the assembly itself. They're robust, redundant, and obvious to the naked eye. In any frame system, the connections are key. If a couple bolts are compromised, or an angle brace is removed, the whole thing becomes much more susceptible to racking, and the >right< way to fix that might not be obvious to future caretakers.
As much as I love your SS beams, they're tough to attach to, and I can't help myself from considering cost at least somewhat. So what would you think of a hardwood/SS flitch beam?
Oh, I actually like the flitch beam idea - not sure how you'd get enough fire resistance though (layer of gypsum between the steel and the wood?)
I think Gypsum is soft enough that it would only serve to structurally decouple the wood from the steel. Once again, though I'm a new tech fan I'd lean on the old ways: big wood to protect the steel. Heavy timber doesn't require the same fireproofing because it doesn't catch the same way as light frame. Fire failure might even be better than just the steel S or W. You were going to have to wrap those with something anyway, because your fire solution of brick doesn't address the horizontals.
This might be of interest to you as well! https://www.realdaniabyogbyg.org/projects/the-minico2-houses-the-maintenance-free-house-tradition
Thanks for the link! Interesting project.
Great here is another one. https://lethgori.dk/brick-house-project/
We should consider the value of the building as a piece of architecture. Design with a great architect and it is very likely that the intrinsic value of the building helps it to make the 1000 years. Imagine Le Corbusier built your house, your house would be preserved indefinitely even if the repairs were costly and materials would need replacement
I agree about the importance of “cultural value” as a mechanism for keeping a building around long-term (I dive into this in part II). But it’s tricky to ensure that this happens - lots of culturally valuable buildings haven’t survived, even buildings by famous architects.
It is March 2024, in about 5 years me and my oldest will be building a small place for him to live. As much as I like this. I will not be in a position to construct this financially . BUT that being said, I read the whole thing instead of sleeping and took me over 45 min to read fully rereading what was necessary to understand it better. I wish I could do this. I ended up here from reading the files of my ancestors in residential school and one of them was asked after graduation to do a questionnaire asking if they are using their education what job they are doing , if they are married and have kids and where they live and do they own their own home and what kind of home is it, he said balloon house so I went to find what one was. And ended up here. I only went to have a smoke an hour and 45 min ago. Now I have been on this page an hour. Thank you for many ideas that some of which I can incorporate
Very interesting thought experiment.
I was surprised you added a fire place.
Given the public sentiment against air pollution and climate change these will likely be banned in the next decades.
Building codes in many countries and regions already prohibit the construction of these.
On top of this, fire place are often a cause of housefires, so this would not help with the longevity.
slate dislikes hail.
any structure you build large and durable enough is likely to be used as a fortress in times of war.
The only long-lasting constructions are those with continuous use- castles and hostels, sometimes resteraunts and spas. The only reason other buildings have survived is as cultural icons or practically uninhabitable structures.
For these reasons, i will be going with a different approach- short sections of enormous quansit hut arches angled for a sloped roof to allow ventilation and updrafts to reduce moisture, overlaid by concrete, to form several hundred feet wide and 5-8 thousand square feet floorplans, all built into hillsides underground but above flood plains and with clear drainage to the front.
The front of the structure will slightly protrude from the hillside and be sloped, consisting mainly of glass with a stone foundation facing at the bottom where an outwardly sloping base will incorporate drainage along with utility functions. Internally the structure will incorporate several large, thick, fiberglass reinforced (which is not susceptible to corrosion) spacing walls with cutouts for doorways and utility spaces, all of which will be brought together by composite lumber. That way it will not be subject to extended bombardment in an attempt to exterminate the inhabitants and the building if burned out can be rebuilt and repurposed.
Have you considered alternative concrete reinforcement methods for the foundation? Something like FRP, fiber-reinforcement, or stainless steel rebar?
And I really appreciate your work here. Fascinating ideas.
Interior design is an intricate process that involves a myriad of considerations, from conceptualization to execution. It begins with thorough research and analysis, where designers explore the client's needs, preferences, and the functional requirements of the space. This stage often involves conducting site visits, surveys, and interviews to gather pertinent information.
One good way to defend a house against war and social change etc (if we are assuming a future not too radically different from the present).
Put it somewhere really remote, and make it last without maintenance. Bury the house into a mountain a kilometre beneath the Antarctic ice.
Then destroy all records indicating it's existence.
The idea being that it sits unnoticed and undisturbed for the entire 1000 years.
This long lifetime building design makes basically no economic sense in worlds where the future turns out to be seriously scifi.
For example.
1) Earth is taken apart to build a dyson sphere.
2) Digital minds running on computers
3) Drexler style nanotech, tiny robots arrange the atoms any way you want.
4) Future giant particle accelerator makes a black hole that destroys earth.
The building might still have historical value in some of these worlds. And if "preservation as a historical curiosity" is something you are aiming for, sure go ahead.
Solar panels are a new construction material, whose energy output offsets its cost, maybe even pay for themselves. Their reinforced tempered glass construction withstands hail beyond what slate can, so even if their output degrades and the occupants choose not to replace them to collect free energy from the sun, they remain a good roofing material. I think photovoltaic panels will remain with our civilization in the centuries ahead like stainless steel or unreinforced concrete, even though more advanced and longer-lasting materials exist. Sized correctly (12lb 100W panels, not the crazy 4’x8’ drywall sized sheets meant for cheap solar farms) they are easily transportable and easy to replace.
Solar panels will power induction cooktops, heat pumps, hot water systems, water purification, and their output can be stored in batteries or shared with a local grid.
Thus you can trade away the chimney and all its structural, drainage, and maintenance headaches. I might suggest an inbuilt roof anchoring system to keep the roof safely serviceable.
just came across this series - fascinating! one way to preserve a building given changing local value is to make the building moveable. We've all seen the pictures of the historic house being moved down the street right? Its seems many of your value concerns over time could be addressed by assuming the building would be moved 2 or 3 times in it's 1000 year life. Your proposed structure over the foundation would lend itself to being more easily moved.