Gabions as Cladding
I’m in zone 5 (though I think it will eventually be more like zone 4) and hoping to build a pretty good house. We’re still in the very early design phases. The program is 3 bedrooms, 2.5 baths, and a 2 car attached garage that will function primarily as a woodshop. The site is decently sized for a city lot at 6000 sf, but not a lot of room once you consider the setback requirements – about 1900 usable sf of land for building.
In talking with my architect, he’s suggested the possibility of using gabions as cladding for the exterior. It’s an interesting idea, and certainly unique. I think the regular grid of the cages and the somewhat random/chaotic texture of the stones makes for an interesting appearance when done well.
Before we make any choices, I’m trying to think through what it might mean to use gabions in this context. How would they perform as a cladding? Would they provide sufficient UV protection to the wall assembly behind it? Are there complications in trying to detail a window or door if Gabions were utilized? Do they offer any particular performance or ecological benefits? Are they ‘greener’ than other options in some way? What about pests or insect considerations?
Hoping some members of GBA might be able to shed light on my questions or – perhaps more importantly – propose other considerations that I should be accounting for in my decision.
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Adam,
The gatekeeper for this idea is whatever building code you are under. Gabions would not fly under ours here in B.C.
- Could you make them work? Possibly.
- Do they perform the functions usually associated with cladding? ? No.
- Would the detailing be a nightmare? Quite certainty.
The sole reason to use them is aesthetic. They have enjoyed a certain popularity in design periodicals over the past few years. If it's something you feel would enhance the architecture of the house then it's maybe worth pursuing, but there is no compelling practical reason other than that.
Thanks Malcolm. It sounds like other materials might satisfy our needs without the additional complexity. From what you're saying, it sounds as if all that detailing would make the construction process more involved and raise the probability of errors occurring at some point along the line.
I do think it would look very cool (especially w/ the right fill), but it doesn't sound like they would be as easy to use in this context as they are for an outdoor wall.
Adam,
I don't mean to put you off it it's something you would like to do. If you wanted to go ahead I would treat them much as you do other open-claddings. That is as being essentially decorative, with the wall and flashing designed to work as though they weren't there, and the gabions being independent of the structure and wall assembly behind. That would avoid most of the complexity.
Malcolm,
I want to be realistic about acknowledging the limitations or downsides of the choices I might make with this house. I also want to be open to the idea that other solutions might also be very suitable, more simple to implement, and offer aesthetic benefits on par with something like a gabion-clad wall.
Adam,
If I wanted to use gabions, my own preference would be to incorporate them as an integral part of the architecture, and in a situation that celebrates their properties as structural elements, not a veneer which could be done in other materials. I think this building does that well.
https://www.archdaily.com/919889/toca-do-urso-brewery-superlimao-studio
I’ve never use a gabion walls for cladding on a house; I’ve used them as retaining walls. Having said that, since gabion walls are extremely air and water permeable, I would think you need to ask an engineer, probably using them only as cladding, with a regular structural wall in place, and a great seal and moisture mitigation plan in place.
I would imagine you could build wire cages 18”-24” wide and fill them with stones, and I imagine there are not that many folks who would build them, but I’ve seen picture of buildings with them, and they look beautiful.
Hi Armando. I agree with you - they would certainly need to be used as a cladding only. I would expect some other wall assembly would be doing all the work, and essentially the gabions would be sitting in front of all that.
I can't imagine how the window details would work, other than making the windows set to the outside of the wall assembly and completely separate from the gabions.
I've looked into some companies that make gabion cages for 'veneers', but even then it's 12" of material in front of the wall itself.
I got to think about how the Taos Pueblo people in NM build their windows and doors recessed deep into the wall, creating shading in the process. So I Googled for a Pueblo façade that would show you their style.
With that in mind, I Googled buildings with gabion cladding, see attached pics. I believe you can build a wood wall assembly, even with outsulation. Install your windows and doors normally, and waterproof over the wall with a fluid applied WRB. Use the gabion as cladding attached with a brick SureTie or MasonPro screwed to the wall and a wire hook or wire tie-down to the gabion cage. They also have ties for concrete, metal and CMU walls. Maybe an engineer would have better ideas to tie gabions down. Good luck!
Armando, do you think that there would be any considerations around wall assembly and gabion cladding? Presumably, they are sitting on the ground, but also tied into the wall. If I did a double stud wall with 2x4, do you think there is any concerns around the framing members being somehow inadequate?
Also, since you mentioned fluid applied WRB - what do you think the impact of an 8" thick gabion would be in terms of UV exposure? Do you suppose they sufficiently block enough sun to avoid degrading the WRB over time?
I would think the gabion would need to sit on a concrete foundation and be tied to the building structure. This would prevent differential settlement issues. The level of anchorage would depend the seismic zone. At a minimum it would be 1% of the dead load.
As for the WRB & UV - I think an additional layer would be needed to protect the WRB from UV & compression from the Gabion System.
I agree that a gabion cladding needs to set on a brick ledge. Most fluid applied WRB can be exposed to the elements from 6-12 months, and some offer permanent UV exposure in open-joint cladding applications. I assume that with gabion walls, much depends on the rock size and how tight is formed.
From Wikipedia: "A gabion (from Italian gabbione meaning 'big cage'; from Italian gabbia and Latin cavea meaning 'cage') is a cage, cylinder or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, military applications and landscaping." When architects use it they generally mean a rectangular cage filled with ornamental rocks.
I'm working on a house right now where the architect had specified gabions. We got all the way to the point where it was time to build the gabions and after some discussion we decided to go with other materials.
The appeal of gabions is that they allow you to do stonework without using concrete, and concrete is a major producer of greenhouse gases. Gabions can sit on the ground without a footing so no concrete is needed for a footing. Whether they are green or not has to be answered with "compared to what?" They're probably greener than a retaining wall of the same size made of poured concrete, but they do involve moving sizable quantities of materials which will consume a lot of energy.
The issue that killed the idea was that we just couldn't find a sub-contractor interested in bidding on the project. Nobody had ever heard of gabions, and in the current environment everyone has plenty of work and just isn't interested in bidding on something outside their comfort zone.
The client had never really been sold on the aesthetics. The metal cages are pretty utilitarian. The idea is that the beauty of the rock hides the cage but it's hard to guarantee that happens. It's not helped that when you do a Google search for "gabion" about half the hits include the word "inexpensive" or "cheap" in their title, and a lot of the pictures you get are utilitarian retaining walls filled with riprap along the side of an interstate or the like.
Some of the other practical issues: we couldn't find a local supplier of gabion cage, which meant the material would have to be ordered and shipped. That always creates the risk of running out mid-project and having the project grind to a halt. The plan was to use the gabions as cladding from grade to the bottom of the first floor. An immediate problem was that the cage material came in 3" increments, and we never did figure out how we were going to fit it around doors and windows. The minimum practical gabion thickness is 6", which would have made it protrude out past the siding, creating a shelf at the top that would catch rain and direct it back toward the house. The house is on a wooded lot with a lot of rodent presence and the gabions seemed to me that they would create a lot of rodent habitat, with openings just the right size for a mouse to get in.
So we scrapped the idea and went with veneer stone instead.
Thanks for sharing your experience as someone who almost used them in a project. You raise some interesting considerations for how it could be difficult to even find someone interested in doing the job. I didn't know 6" gabions were possible - thinnest I could find were 12".
The consideration for water management is also a good one to factor in. I have wondered about this part -- Gabions are so thick, they would presumably block a lot of water just by having a big pile of stones in front of a structure, but they have a lot of open spaces in them as well.
Herzog and de meuron used gabions for a winery and addressed the critter issue by using tighter mesh cages at the bottom, filled with smaller rock. In that case, it was to discourage snakes. I think that would be a must for any residential project that did employ them.
The 6" thick gabions would have had to be connected to the building with ties, they wouldn't be free-standing. Which adds another layer of complexity if you're trying to use them as open cladding.
I wanted to follow up on something you mentioned. Regarding the gabions directing water back towards the house. Was this something you saw, or more the observation that the shelf formed by the top of the gabion would be obstructing water from flowing down and away from the wall assembly?
It seems like there would be potentially some water that would flow backwards, but other water might just as likely flow down or forwards. I suppose if one was really meticulous, they could try to direct the flow of water. I also would imagine that gabions with a gap between the wall assembly would drain very well.
The architect I'm working with has the gabion walls projecting out partially from the green roof, which does raise a little concern, but that concern is by the 4" or so of rock that water would have to go through to hit the WRB.
It was a a hypothetical concern, we never got to the point of installing the gabions.
I agree that with a gap water flow shouldn't be a problem. The problem then is how you keep them from falling away from the wall. If they are touching the wall, I don't see how you can control water flow. Water likes to form a stream and follow surfaces and if the surface it happens to be following is the wall of a house, bad things happen.
What little I've seen of details for doing a gabion 'veneer' seems to suggest that the cages are tied to the wall and/or there is some type of post creating rigidity.
Assuming for a moment that the gabions could be stood off the wall by 1/2" or so, it seems like that would at least mitigate some of the issue. You would still have some points where the wall and gabions tied together, but I'd think the amount of water flowing from a the basket to the attachment hardware to the WRB would be relatively low?
I looked at gabions a few years ago for a project. I found and considered https://gabion1.com/stone_cladding.htm They are in the Southern California Area, so close to the project. This mfg sees to make more architectural grade gabions. Project fell thru-
I am not sure what trade we would have gotten to install them.
I've thought that landscapers might be the ones to do the work, since they tend to be the ones with the rocks.
It's not obvious to me how the details would work if using a stick framed wall. With a CMU block wall, it makes a bit more sense, but with wood it just seems like you'd have some real challenges connecting the gabions to the wall assembly, and you'd have to do a lot of planning to thermally break those connections.
Sorry, the appeal of this idea eludes me. I would only think it appropriate in a place with little rain and a threat from fires. But I do like the notion of using a smaller mesh to keep out critters. I'll remember it when I'm cleaning out the shed snake skins and rodent nests from my 8 foot high stacks of firewood. Snakes love to get up near the roof where it's warmer.
I would also not take a job where I had to stack something that hard and heavy around windows. Surely you could protect the glass with plywood -to a point.
Herzog and de Meuron architects spec'ed gabions on a winery project many years ago and discovered that snakes really, really like them. I believe the solution was to have an audio recording of raptors playing near the gabions to keep the reptiles scared.