Review of Boxabl SIPS Prefab House
The company Boxabl has created a metal SIPs (structurally integrated panel) house that has caught a lot of folks’ attention.
The main reason it has gone so viral is that it promises it all – fast, easy, cheap, resilient, and healthy.
My job as a Building Biologist is to review homes for durability, indoor air quality and resilience to mold.
It may be cheap and fast, but is this home a durable and healthy home?
First, is it “eco-friendy”
The basic structure of this house is a steel and styrofoam (EPS) structural panel. This is very safe even for those with chemical sensitivities. That part has practically no offgassing and I am a big fan of SIPS.
They also use MgO (magnesium oxide) board on the interior surfaces which is generally safe option as it has extremely low or no offgassing in my experience.
It’s not clear how that is attached to the walls in this case, it’s likely glued on, which could be a problem for offgassing. (More on in the inherent risks of MgO against steel below).
The flooring appears to be glue down vinyl, though they have described it in different ways. The countertops and tabletop are laminate (which is a melamine plastic glued onto a substrate which is almost always MDF). And the interior cabinetry is conventional (which is typically particleboard and laminate).
These three elements will contribute to offgassing – plasticizers, and glue from the vinyl floor; glues and formaldehyde from particleboard based cabinets; and glues and formaldehyde from MDF based laminate countertops.
While this is not high in offgassing per se, at least according to conventional wisdom, it absolutely could be too high in VOCs for those who are sensitive to formaldehyde.
At this time the interior cannot be customized and it includes all the interior finishes other than the bed and sofa. They do plan on offering customizable interiors in the future.
Even though it would be quite easy to choose your own healthy floor and cabinets in theory, it would likely be difficult to remove the already glued down vinyl.
With just a little more effort and planning, they could reduce offgassing significantly by choosing better cabinets, countertops and floors.
(Though keep in mind we do not know the exact materials or brands used in the Casita so I am making some very educated guesses based on videos and what is most typical and economical right now).
Is it a durable design?
In general, metal SIPS are very resistant to mold because as long as the wall remains laminated they are immune to condensation problems. Moisture cannot get into any wall cavity to find a cold spot to condensate.
If they are well connected and well sealed then they could also be durable against leaks. The waterproofing will depend on how well the seams are connected. I owned a metal SIPS trailer (Camplite) that was very leaky!
There are a number of concerns I have with this house:
- There is a clear negative lap at the bottom of the first piece. It’s not just an exterior trim detail, it’s integral to the design. It’s risky in my opinion to have a negative lap that is only help together with caulking. I would suggest a liquid membrane or tape + caulk would be better there.
- It’s nice that it unpacks quickly into a full livable house but how are all those seams waterproofed? I do not think we have enough information on that right now.
- Because it’s done almost entirely in a factory we would need to see a detailed factory tour to see if this is a good design. There are so many details I would want to see including how the windows and all seams are waterproofed.
- The house, like all prefabs, needs to be seen in person, especially during installation, to see if there are any areas vulnerable to water. My prefab post goes over the due diligence needed here.
- MgO and steel have not gone well together in the past. In Denmark, massive problems (and lawsuits) resulted when salts naturally leached out of MgO board and corroded the metal in the buildings. It’s not clear, even in recent tour videos of 2022 if the MgO is placed against the metal or if the SIPs are metal-foam-MgO.
- The bottom of the house is metal presumedly, so that, in my opinion, should definitely not be placed directly on concrete on directly on any type of ground like soil.
- The website says that Boxabl “doesn’t use lumber or sheetrock” and in an email they said “we do not use wood or materials that can rot or mold”. But in multiple videos, wood appears to be the framing of the edges of the SIPs. Hidden wood in a metal-based house is a problem for hidden mold (potentially) in my books. Even the window rough openings are framed with wood – what happens when a window leaks?
Is this a reliable company?
Still in development
When I first wrote this we didn’t know if this is a reliable company yet. As I discuss in my general prefab post I never go with the prototype of a prefab. They commonly have problems.
When I first wrote this blog post, the company still needed to raise 10 million dollars to be in full production. As of mid 2022 they do have a factory set up in Nevada and are still expanding into full production.
As of September 2022, no individual customer has yet received a Boxabl, and some put down their deposit almost two years ago. They will not be producing homes for individuals until the second factory is done.
They are a lot more established since I first wrote about them, but I am still wary of all prototype home models.
On the fundraising page it says “early investors get a discount”. When someone asked what the discount is they responded “It is possible there will be a discount. We haven’t announced it yet.”
In one of the videos, the rep states that you could install this without a foundation or permit. That sounds ill-advised.
It did not sounds like the reps actually know what the floors are made of in early videos.
Elon Musk Involvement
It definitely adds legitimacy that Elon Musk was living in one (and now uses it as a guest house). But it’s unclear whether he is backing the company or not. His area of expertise is not in construction but it would be great if he did lend his mind to making this a better built home than what it looks like. It has great potential to solve the problem of lack of affordable and healthy housing around the world. But in my view this house has not proven itself yet.
Customer Reviews of Boxabl
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Carla Bonita Fox says
If steel foundation cannot be placed on concrete, what can you use as a foundation?
not on a concrete slab but up on concrete or wood beams.
Charlotte Wolter says
Thank you for an intelligent review of Boxabl’s prototype. While I’m not overly concerned about off-gassing issues, I appreciated that your review covered a wide range of possible problems and unanswered questions. I wish them well, if they can move beyond the prototype stage to sellable homes, and if they answer questions, such as those you raised.
Their web site struck me as more of a solicitation for investors than a serious sales offering. Also, my years as a technology reporter taught me to examine carefully the language used in SEC filings. I found little there that confirms sales to anyone. Sales to an entity, such as FEMA, likely are contingent on actual delivery and, after that, acceptance by the buyer. We shall see if any of that happens.
Will K. says
@Charlotte Wolter – Regarding your careful SEC search examination, did you miss the part where Boxabl completed and delivered 155 units to the federal government/a military base in northwest Florida (back in May/June 2022) for $9.5 Million(?)
I absolutely disagree that any Musk involvement would be a benefit. The guy is a psycho out to destroy civil society, is a practicing racist and has zero business integrity. This would be a huge negative for me.
Mike Montague says
Thanks for looking into Boxabl. As you’ve said, there are many concerns that can’t be reviewed without an in-person inspection. My question is about snow load and to a lesser degree, wind load. Have they published anything that addresses this issue?
Boxabl has not made 1 penny yet in revenue, due to the fact that they do not have the proper permits to ship them to customers. Yet they have taken millions of dollars from buyers and investors. Boxabl claims they had a 9 million dollar contracted order with the government but there is no proof of that. Also, they are not mold proof houses. Do a little research and you will figure that out for yourself. Also, the owners have had a questionable past. Do your research before buying or investing! Theranos part 2!?
There is no mold proof house is absolutely right. I have seen mold growing *in* foam on multiple occasions. That is why I’m stressing that those areas of concern need to have solutions (and maybe they do, but we need more info at best).
Toni Taylor says
Here’s their Government contract;
Mike Montague says
I read the SEC filing. In its Valuation section (page 24, paragraph 3) there is a sentence that “…the federal government has placed two purchase orders totalling $9.2M.” It goes on to talk about the related COGS and expenses expected to be nearly double that amount.
Also see Notes to the Financial Statements Note 8 – Commitments and Contingencies – “the Company signed two purchase agreements with a customer to sell 156 Casitas units, for a total contract price of $9,245,574.” It does not mention the customer by name.
You can read about the 9 million dollar order in their stock offering, I think it was FEMA. If you read carefully however, you will discover that each of those units were produced at a loss, I think it was about 5-8 thousand each.
Will K. says
@ John says – How much research have you actually done on Boxabl(?) At the time of your post, Boxabl had already completed and delivered 156 units to the federal government (to a military base in northwest Florida) in May of 2022, for $9.2 Million. I was actually able to find the following link in less than 60 seconds via Google…
A Hill says
I’m very taken with the idea of a house that can be delivered so easily, for the price of a casita.
However….I absolutely do not want to live in a house that I can’t work on myself, that has synthetic features that will age badly, and that has an overall aesthetic of artifice and sleek modernity (just not my thing, is all). Still, I’ve been considering whether I could live with that last aspect of the Casita, given it’s affordability factor.
Only, doing my due diligence in terms of trying to learn more about the details of this product has led to less and less confidence in the company’s ability to spend my precious home-buying dollars wisely. For one thing, the easiest, most obvious questions are not being answered by their website, and there is no obvious way to connect with someone who can answer. That is irresponsible, for a company that wants a big chunk of cash. Also, looking at their contract that you agree to when you reserve a Casita, they repeatedly state that they make no promise that you will ever actually receive a Casita. That’s probably some kind of legal standard in a situation where the production is still being figured out, but…nope. Why would I make a promise like that? Especially since they also state that you promise to buy one? Sounds like they reserve “backsies” for themselves. Again, this might just be standard contract stuff that doesn’t actually work out in the real world the way that it sounds on paper, but nope.
Also, the product is so trendy. The basic Casita is bound to be vastly improved upon in all sorts of ways. If you buy the basic model now available, won’t you have Casita-envy/regret in a years’ time, when they start to offer the enticingly expanded options they hint at on their website? I’m imagining myself settling for the basic Casita, only to find that in a year or two, I could have had something more flexible and customized. In any case, the only way I could live in a Casita in my state, would be if I ordered, say, the basic, plus the blank room or two bedroom add-on they don’t yet offer but plan to offer, and put them together to make a house big enough to qualify as a house here.
Then there’s the whole, prototype issue. Not just with the end product, which you know is absolutely going to have issues, but also with every aspect of production itself. The factory is new, the team is new, the product is new. There will be bugs to work out. The lack of depth or thoroughness of their website leaves me in doubt as to the foresight and understanding of/experience with their customers’ needs. Really want this to be the simple answer to my own housing problem, but it’s not looking likely.
Yep, I agree with all of that!
I also had first thoughts on how to make repairs and change out broken appliances or marred flooring…. are materials and appliances modular enough to be easily replaced.
A fun comparison would be of similar products. They’re in Vegas and they’re not producing any actual product. There are at least two area companies who seem to be. I just noticed this one in the desert; I live nearby: Far Out Tiny Homes https://bit.ly/3SbxCcF
Will K. says
@Bdl – What(!?) Why would you spread such misinformation(!?) If it’s due to some kind of jealousy issue, I could see how a competitor would be jealous, given how BOXABL not only has an amazing product but also how BOXABL is “actually” producing their amazing folding homes as I type this, and has actually been building since 2021. In fact…BOXABL…is getting ready to open and ramp up production in their SECOND factory shortly(!)
Will K. says
@A Hill – How would being an early adopter/owner of an early model Boxabl Casita be any different than buying most any other consumer good/s(?) There isn’t a single consumer product that doesn’t go through some kind of change/upgrade over time. Another really nice/awesome thing about a Boxabl, is that they are modular and can be re-folded… so if f one were to buy a Boxabl and outgrew (ie) the Casita model, one could simply add on an additional unit/s.. And as if those options weren’t compelling enough, if one were so inclined, one could actually refold their Boxabl and sell it to someone else, and purchase a larger/more advanced Boxabl, and set it up on the same property just as easy as the first model. The portability and versatility of a Boxabl, is absolutely game-changing and the company is onto something huge, as far as modular/prefab housing is concerned!
Prototype of a modular home/trailers is definitely a problem if you are in the building industry you know this kind of thing will have problems, almost certainly. I have already pointed out a number of areas that don’t look finalized and look like they will have problems.
You’re obviously working for the company!
Janis Bell says
This is a great review! I went onto the investor’s page to see if I could get more information and if someone would call me. One of the owners wrote me and answered some of my questions about liability. I thought they were naive to assume that a metal SIPS building with wood and MgO board could never mold, even if flooded (this claim was in a promotion) and rather than seriously look at that possibility and consider their liability, they discarded it as impossible.
First off, the SIPS will not be 100% covered in metal because there are going to be cuts for the plumbing and electric. Dust will get into these places unless they are very well sealed, which I doubt they will do. All it takes for some mold in these dark places is a bit of dust and some humidity.
Their concept of building houses like cars is catchy but just think of all the lemons that come off the assembly line? And all the things that break over the first few years? Building four houses in a day means assembly line quality and assembly line errors. You are so right to guide people to a more established product.
Yeah I have seen mold growing within the cells of EPS. Wish I had photos because apparently, most people don’t believe this. But even if it doesn’t mold it could still possibly have problems with water or with the MgO corroding the steel that would still be an absolute pain and might not be fixable.
Michael S says
I contacted them today. They do factory tours in Las Vegas. It would be nice if someone could get out there and demo this for us.
I will contact them and see if they can customize certain parts in regards to the points your raised.
They seemed very helpful and responsive.
It’s not something I would look into further.
What would be better than steel? Is it just rigid foam ? What kind of glue?
Kimberly Nicholas says
Good to know People don’t have time to get scammed. We are already trying to secure affordable housing
There is so little information about this company available. When I Google questions re this casita the same sites and videos come up with the same lack of information. I can’t find a way to contact anyone. How can I consider sending money for a purchase if I can’t speak to anyone. I need to know what the total height of two casita’s one on top of the other and I can’t find the answer anywhere online nor a way to ask anyone.
I wouldn’t go with something that new that we don’t have enough info on
Will K. says
@ Judy – How is it you are unable to contact Boxabl(?) They are a legit company located in Las Vegas, Nevada and are also available/very transparent on nearly all major social media platforms. I’m not sure how much easier it could be to find and contact them, seeing how a 30-second Google search (using the search term “How to Contact Boxabl) returned the following information……
“Boxabl – Overview, News & Competitors | ZoomInfo.comhttps://www.zoominfo.com Headquarters: 5345 E N Belt Rd, North Las Vegas, Nevada, 89115, United States ; Phone Number: (702) 500-9000 ; Website: http://www.boxabl.com ; Revenue: $9.2 Million”
“Please send us a note with your name and best contact number to [email protected] and we will respond to you as soon as possible. Thank you for your patience and for your interest in Boxabl.”
Investor BE WARE. Elon must confirmed that he DOES not live in a Boxable. So the company Boxable posting a picture of Elon Musk and 2 or three news articles on their website is disingenuous at best.
What we know so far:
NO EXACT DATE for shipping
NO ONE who actual took delivery on a model
NO latest news
I think this is a scam because the Casita model was shown to Dr Ben Carson way back in the early years of the Trump Administration, and till this day NOT ONE person has taken delivery on a Boxabl that I know of yet.
I hope they are HONEST
I hope they are not a scam
I wish them the best, but they need to have better EXACT information
Correction. Elon Musk DID have his Casita delivered. Confirmed by him personally. Unless you know better than Elon himself, I would put that one to rest. Ob the other note, no one claimed that Elon Musk actually lives in one he received.
Please stop spreading FUD for no reason.
Actually they DID deliver to the government a large order – they lost money on each however. read the docs they had to provide to sell stock.
Cynthia Macri says
When you add up the final cost of the Boxable Casita, it becomes comparable to the cost of a tiny home. Plus, unlike tiny homes that can be moved, Boxable homes require a permanent placement, which means you need to own land. What land owner is going to be ok with a permanent fixture on their property — even if it’s in the middle of nowheresville? IMO the Casita is great for those adding a second dwelling (ADU), and if enough are built, then they may make a fraction of a dent in the current housing crisis. Most ADUs will be rentable properties, which means people are still subject to a landlord’s restrictions: No pets, no smoking, no parties, no…no…no. As someone who has two dogs, finding housing that allows dogs is near impossible. So, even if you are lucky to land yourself an ADU, landlords still have all the power in deciding who can rent. That’s status quo to our current situation. And, interestingly, I’ve been searching for tiny homes to rent — they’re comparable to rent prices in homes in the middle of the city because they’re trendy!
Regardless, hopefully Boxable will offer off-grid models as well. And while I don’t like the shoebox layout of a tiny home, the Casita’s interior isn’t the nicest either. Maybe Boxable will eventually offer an upgraded model that can be mass produced to keep the cost down.
To Americans who complain that they can buy a house for less than the cost of a Tiny Home, Canada is a completely different market. Canada’s the second largest country in the world with a population 1 million less than the state of California. You have options we don’t because most of our population is concentrated in just several markets, so the demand always usurps the supply. Sure, there are affordable places to live here also, but who wants to live in the middle of nowheresville? Check out these two recent listings in Toronto- — sold for over asking:
So, yeah, $100,00+ for a tiny home is a bargain.
personally a fixed tiny home is my preference that is attached to sewer. I do not have a desire to live in a portable tiny home. Thus Boxabl is a viable option for people like me.
Will K. says
@ Cynthia Marci – I’m not sure how much research you have actually done on Boxable and/or where exactly you’re getting your information, but Boxabls are actually designed in such a way, that if a Boxabl owner were so inclined, they could actually refold their Boxabl and move it and/or sell it to someone else who could move it to an entirely new/different location. I’m not sure why, but there is a surprising amount of bias and misinformation here in the comment section on this page. Does anyone actually perform any actual, non-bias, professional research here, or is it just one big “sour grapes” free-for-all(?)
Thanks so much for the great work you are doing! I have referred to many of your articles over the years when moving and renovating.
I am seriously considering buying a Boxabl (on the wait list already!) as we are downsizing and relocating. I was planning to replace the countertops and floors with nontoxic options however, our budget just may not allow for that in the first year.
We plan to seal the cabinets with sealer from Green Building Supply. I wonder if the floors and counters can also be sealed? We have an Austin Air filter so we hope that will help a bit in the meantime. My sensitivities have greatly improved over the years with my holistic healing practices, but still pretty cautious.
Would love to get your thoughts on this, or any other recommendations on a budget.
Many blessings to you,
PS: Also curious to hear your thoughts on EMF with the steel walls. I am sensitive to emf, so don’t have wifi or smartphones. However, I wondered if living in a home made of metal would be ok? Maybe even protective?
Hi, I don’t cover EMFs but I do have a few articles on mitigating offgassing.
Rachael Bonsignore says
I was just watching some YouTube videos on Boxabl houses and my big question was, of course, how well do they perform? I decided to google “Boxabl houses and condensation”, and your article came up! You are just the kind of person I would want to hear from on this! I soaked up what you had to say about it like a sponge.
Great to hear your positive view of metal SIPS panels, and also your concerns about how waterproof the seams are. Like you, I was also interested in how much off gassing there is inside, so your comments were very interesting to me.
On one of the videos, I believe a founder of the company said they did all kinds of tests, including tests on mold and water resistance. I would like to see the results of those tests. But the real test we would like to see the results of is the test of time. How has one of those units done outside in the field.
Good job, Corinne. I would like to post this article in the Facebook mold groups.
Thanks Rachael! Yes please share, I had not got around to sharing it on FB yet.
“In one of the videos, the rep states that you could install this without a foundation or permit. That sounds ill-advised.” Yeah, that sounds really irresponsible to promote or attempt. Sure, some places still don’t have zoning regs in place, but most do. Seems like you’d be folding right back up and moving on, if a planning board, city/town manager or city/town council caught wind of your new, unpermitted dream home. And thanks for caring about offgassing and building health: so pleased to see this topic getting the attention it absolutely needs!
Yeah, metal right on the ground would be a no from me!