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Loadbearing glass bricks

more light, fewer windows
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(+12, -1)
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I think it would be good to be able to build houses out of glass instead of concrete bricks. Okay, so glass bricks do exist already, but these are all reported as non-loadbearing, as far as google can see.

So, why are current glass bricks not loadbearing? Some of them are hollow, but that isn't the full story, because some are solid. It may be that they can't take the load, but I hope that's not it. I like to think that the glass blocks are able to slide out from each other, as they have relatively flat surfaces at the top and bottom, and don't key well with mortar.

If so, the solution is to cast the blocks with complementary humps and dints. A bit like lego-bricks, but less pronounced, and as a continuous curve rather than toggles.
Typically, you'd build with the bumps facing up. And you'd build in the traditional half-offset brick mode.

I don't know whether you'd be able to get away without mortar. Any subsidence and cracks may be a serious problem. Some sort of yielding material might help, but if a crack does occur it may be fixable using a windscreen repair system.

You may say that glass is expensive to manufacture, needing a lot of heat. But so do clay bricks! And the concrete used gives off additional CO2 during preparation into the bargain. Also, glass can be recycled - the UK has a surplus of green bottles. Grinding them into aggregate for road-surfacing just isn't that impressive. Shiny green bricks though would be some real upcycling.

Loris, Nov 04 2008

Buckling Design of glass elements under compression http://www.glassfil...y/13/article821.htm
"Glass, a material that has been used for a long time in windows as a filling material, has much to offer in this regard due to its very high compressive strength and transparency." [zen_tom, Nov 04 2008]

Glass bottle wall http://en.wikipedia.org/wiki/Bottle_wall
Prior art [8th of 7, Nov 04 2008]

Bottle house http://en.wikipedia...ve_Bottle_House.jpg
Recycle ... [8th of 7, Nov 04 2008]

polystyrene walls http://www.iom3.org...-based-brick-fa-ade
[williamsmatt, Nov 05 2008]

(?) Glass Houses Glass_20Houses
by [UnaBubba] [hippo, Nov 05 2008]

Room built of load-bearing clear bricks, no mortar http://www.prweb.co.../02/81592/Igloo.jpg
[ldischler, Nov 05 2008]

Laminate house http://www.ultimate...tv/article.php?id=6
Built of vertically laminated glass panes [Loris, Nov 06 2008]

foam glass http://www.foamglasinsulation.com/
[afinehowdoyoudo, Nov 08 2008]


       I first this was a newly discovered tongue twister. Say vocally "LoadBearing Glass Bricks" 10 times without giving a gap.
kamathln, Nov 04 2008

       //It may be that they can't take the load, but I hope that's not it.// True engineering spirit, precise, and based on reasoned calculations and careful experimentation. I did a google, and found someone who's thinking along your lines, only with additional facts.
zen_tom, Nov 04 2008

       I'd like a house built out of such bricks. [+]
Srimech, Nov 04 2008

       Walls of glass bricks are commonly over 2 metres tall, so they must be load bearing to some extent.
hattiel, Nov 04 2008

       Glass technology has changed out of all recognition over the past 20 years. This may be possible soon.
wagster, Nov 04 2008

       Would you be able to throw stones? [+]
ed, Nov 04 2008

       unmodified glass will sag over time, not sure if this would be a factor, also seems like an energy intense, low R, high disaster danger material.
WcW, Nov 04 2008

       //energy intense, low R, high disaster danger material.//   

       Sums up 99% of HB ideas.
MikeD, Nov 04 2008

       It's an obvious tagline.
normzone, Nov 04 2008

       The outer wall of a building does not have to be load bearing. Skyscrapers are built on metal frames. So you could have some kind of frame supporting a glass wall on each floor.
Bad Jim, Nov 04 2008

       Would you be satisfied with a metal or wood frame with glass filling in the gaps ?
FlyingToaster, Nov 04 2008

       //You've given me a wonderful design idea, [Loris].//   

       I'm glad to be of service. If it pans out, I hope you'll show us pictures.   

       //unmodified glass will sag over time//   

       It seems you're thinking that glass is a liquid. Current opinion seems to be that it isn't.
In some ways that's a pity, actually - if it were the structure would be self-healing.

       //...energy intense, low R, high disaster danger material.//
I've already touched on energy usage - although as zen_tom points out I've not done exhaustive research. Glass just has to melt, while clay bricks are fired for several days - admittedly at a somewhat lower temperature. I'm also assuming we're using recycled glass, which is cheap, plentiful (dependent on colour), and doesn't require mining infrastructure.

       If by 'low-R' you're referring to insulation, then according to the references I've looked at, glass seems to beat brick. And I don't think there's anything in particular to prevent incorporating small voids to improve insulation further.   

       Regarding the danger element - I think we can assume it would go through some thorough testing just like all building materials.
Loris, Nov 04 2008

       //So you could have some kind of frame supporting a glass wall on each floor.//   

       Windows, you mean?   

       //Would you be satisfied with a metal or wood frame with glass filling in the gaps ?//   

       I'd prefer them to be essentially a replacement for fired clay bricks. Otherwise - they pretty much exist already.
Loris, Nov 04 2008

       It would probably make more sense to build the structure with a metal frame and then just fit in large double-glazed units, which would be far more thermally efficient than glass bricks.   

       Walls - and buildings - have been sucessfully constructed using unmodified glass drink bottles and a fairly standard mortar for the jointing.   

       It is not recorded if the constructor was actually responsible for emptying all the bottles beforehand, but if that were the case, it might account for the poor quality of some of the jointing .....   

       "In 1960, Habraken designed the WOBO (World Bottle) for Alfred Heineken. The WOBO is a stackable beer bottle capable of building a bottle wall. Initially developed in response to the the lack of affordable building materials and the inadequate living conditions plaguing Curacao's lower-class, the WOBO is a pioneering example of industrialized recycling and adaptive reuse of materials."
8th of 7, Nov 04 2008

       // It seems you're thinking that glass is a liquid. Current opinion seems to be that it isn't.//   

       Hear hear. Halfbakers everywhere must unite to debunk the liquid glass hypothesis. Some years ago, an individual realized glass had no crystal structure, examined some medieval cathedral windows, noted that the panes were fatter on the bottom, and deduced that glass was a liquid which had begun to flow over time.   

       The hypothesis was incorrect, as can easily be percieved by noting the fact that obsidian is natural glass, chemically identical save for a few impurities. If glass were a liquid then the obsidian stone tools found in the archaeological record would surely have all become unrecognizable puddles by now... seeing as how medieval glass is hundreds of years old, and the stone tools are by and large thousands, or even millions of years old. So, Glass is not a liquid.   

       Unfortunately, glass does shatter under pressure, so there would likely be a very significant upper limit to the possible weight applied to such a structure, and shifting foundations could destroy the whole thing.   

       All the same, an interesting side question would relate to temperature control:   

       In the southwest, using structures with solid walls of a certain thickness will allow the heat from the day to be slowly conducted through the walls, and not reach the inside of the building until nighttime. Likewise, the cooling from the night slowly conducts in, and arrives during the day time. Glass bricks would allow for temperature to be conducted in a similar way, but would also allow light to be radiated through almost instantaneously... doing... uhh... what?
ye_river_xiv, Nov 04 2008

       where clay bricks are used it is very rare for the internal surface not to be lined with plasterboard either mounted to the inside of the bricks or sitting adjacent on a metal frame, this is called a cavity wall system and is prevalent in most domestic construction. the internal lining would reduce the effectiveness of see through walls (if this is one intent of glass brick idea)   

       this cavity and inner layer also improves the thermal performance. masonry has low R-value but clay bricks contain small air pockets which improve thermal performance. there is also a thermal mass effect whereby core fillling concrete blocks creates a lag effect for thermal transmission allowing heat to be released diurnally (at night). double glazing is the same principle. insultated interlayers are used in modern glass to improve thermal performance, this would be difficult for moulded form. interlayers are glued between two already cast sheets of glass.   

       in terms of installation glass bricks would be very heavy and difficult to move. they would also be subject to chipping due to brittle nature. mortar joints are reqd to be weatherproofed, this could be a silicone type seal but this is environmentally unfriendly and expensive.   

       the system you are describing on a performance/erection basis is better done with polystyrene, refer link. include sustainability in your criteria and you are back to mud.
williamsmatt, Nov 05 2008

       sp. nocturnally
pertinax, Nov 05 2008

       //allow light to be radiated through almost instantaneously... doing... uhh... what?//   

       Well, wouldn't it behave rather like an unusually robust greenhouse? In that case, it might be more usefully employed keeping, say, [wagster] warm in the West of Ireland than steaming up [UnaBubba] in Queensland.
pertinax, Nov 05 2008

       // I did a google, and found someone who's thinking along your lines, only with additional facts.// Marked for over-long tagline.
MaxwellBuchanan, Nov 05 2008

       //in terms of installation glass bricks would be very heavy and difficult to move. they would also be subject to chipping due to brittle nature. mortar joints are reqd to be weatherproofed, this could be a silicone type seal but this is environmentally unfriendly and expensive.//   

       All that is also true of clay bricks though. For sealing I'd consider epoxy resin. (I think that's probably what windscreen repair systems I've already mentioned are). As you can already buy glass with bubbles in, I don't think putting bubbles in for insulation purposes will be an issue.   

       //...the system you are describing on a performance/erection basis is better done with polystyrene, refer link.//   

       The critical word in your link above is 'façade'. That's not a structural building material. Also it's not even slightly translucent.   

       I must admit I was a bit put aback by zen_tom's comment. I'd have thought he'd be familiar with the Bakeries raison d'être by now.
Loris, Nov 05 2008

       Sorry Loris, it was just a gentle bit of jibery aimed at a sentence I found genuinely funny in the bakery context - no harm intended - as it happens (not that it's any consolation) I think it was something in this idea that led me to thinking about dry-stone walling, which developed into an idea of my own - In that one, I suggested concrete, but glass might make an excellent alternative - in fact, reclaimed, semi-translucent glass (or for more colour, the brightly coloured but generally opaque Byzantinian smalti) might make exceptionally economic houses due to the (literal) greenhouse effect - plus, semi-translucent or almost-opaque glass, as well as being relatively cheap to produce (probably, facts again) means that you don't need to worry about walking around naked indoors.
zen_tom, Nov 05 2008

       Some of those privacy arguments were aired at length in [UnaBubba]'s "Glass Houses" (see link)
hippo, Nov 05 2008

       <loris> you are right the polystyrene is a facade system. I was trying to point out, most masonry or block in domestic construction construction is a facade system, with internal framing behind. concrete blocks are infill usually (ie. non-loadbearing) and when they are loadbearing, must be core filled (meaning filled with steel reinforcing and concrete).
williamsmatt, Nov 05 2008

       In the UK I believe most new brick buildings have cavity walls, having an inner wall of breeze-block, an outer wall of brick, and between them a 'cavity'. In new builds the cavity nowadays is usually part-filled with insulation of some kind.   

       For a glass-brick wall to transmit light obviously all the main components have to be at least translucent. I like the idea of combining both walls into one block (with a sheet of small bubbles forming the cavity). However, that's probably stretching the term 'brick'.
Failing that, you could use a transparent or translucent insulation system, like nanogel or kalwall. Or perhaps bubblewrap.

       Perhaps there's an alternative system. Glass brick on the outside, double glazing on the inside. That might just qualify the whole wall as 'window' if it helps it pass the regs.
Loris, Nov 06 2008

       Glass is surprisingly strong in compression. Torsion or shearing stress, not so. To counter this and still use glass, you could introduce fibreglass.   

       Glass is also very smooth. Mortar is going to be a problem. The fact the mortar can't exert shearing stress on the glass brick will result, not in shattering bricks, but rather a gradual slide of your walls outward. There are certain geometries that will preclude this, however. [edit] as seen with the icehouse in [ldischler]'s link, (although there might be some fusion of bricks. i.e. mortar)   

       The big difference here, surprised no-one has said it, is that bricks are "sponges". Lots of air. A brick is a hard, strong sponge. A solid glass brick is all glass.   

       The closest you get to a *real* glass brick at the moment is ---- Silica Aerogel. Added advantage of silica aerogel, lots of light, very little infrared/heat, very little weight/stress.
4whom, Nov 06 2008

       After a bit of online research I've found that the reason for cavity walls in the first place was because of bricks porosity. Rain can soak through solid brick walls, basically. So originally the cavity was where water could flow down and out a drain in the bottom. Retrofitting insulation can cause problems under such circumstances.   

       Given this, it may be that one doesn't need a cavity system in glass walls in any case, provided the seal between bricks is good enough. (Although I still like the idea of having glazing on one side for insulation purposes if necessary.)
Loris, Nov 07 2008

       Foam glass blocks would work well for this. Already available as insulation in some parts of the world. No reason (except maybe cost) they couldn't be used as the bulk of a building.
afinehowdoyoudo, Nov 08 2008

       fantastic - after the year I've had at GirlGuiding we'd love this!
po, Nov 08 2008

       what if you were naked inside?
andrewdudex, Nov 09 2008

       An appeal to container makers would be of benefit. Containers made in uniform shapes and colors, designed to fit directly into professionally pre-designed buildings, would be great for developing nations especially.   

       Unique containers are part of the marketing and branding plan for companies. Makers convinced that the "green" aspect of the designs, as well the fact people would buy more of the product to collect building blocks, would be a sales asset, not a liability.
Sunstone, Feb 20 2010


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