My mother asked me a rather odd question (well, odd for the fact that she asked me–I’ve never built so much as a birdhouse). She wants to know if it would be possible to build a second story onto a mobile home that is not on a foundation.
My reply was, foundation issues aside, I don’t know if the walls could even support anything other than the roof currently on them.
She then returned with a plan I have no response to at all, so I post it here:
Suppose eight concrete columns were pored around the building to a depth greater than the frost line (Would they need to be that deep? Bedrock is only a foot or so down, there’s very little soil in the area). The house is jacked up at one end, a steel beam is placed between the two columns, then the building lowered onto it. The same is done for the other three pairs of posts. The end result is the mobile home on a steady base.
Now suppose those columns continue up out of the ground and over the present height of the walls. Again, beams are placed between the columns, over the building (roof removed). Could a second story be built with the majority of its weight now being taken up by the columns running around the perimeter?
Frankly, I don’t know, so I ask you.
A bit of information: The area is Franklin County, in central Maine; the building is 15 feet by 70 feet; the budget is flexible, but ideally no more than $100,000.
I believe the idea also includes something about the upper story being wider than the lower (going out to the edge of the columns), and the recess made below being a wrap-around porch.
Ok, first of all, you can’t do anything like this until you get a building permit. There’s no way in heck yer gonna get those planes approved unless this column design is approved by a liscensed engineer. We’ve got pretty strict building codes in this country which is why we don’t get those building failures like you see in places such as Turkey,
That said, the columns are gonna need some rebar (steel reingorcing bars). You’ll get a fair amount of flexure (bending) and CMU is only strong in compression, not tension. I’m not sure how the floor of a mobile home is designed but you’d have to make sure the beams support the mobile home in the same place it would be supported on the ground. and then there’s the issue of stairs. Are the stairs going to be internal so you can get between the structures or are you gonna have an exterior staircase. Anyway, you’ll need a structural engineer to design.
On top of all this, the proposed structure is gonna be ugly as sin. I think with the budget you’re talking about, you could get something designed and built that woudl look a lot nicer than mobile homes on columns…
There’s a house for sale for under $100,000 that she’s considering buying, but that would necessitating leaving the property she’s currently on and is rather attached to. Thus this scheme.
Only the lower story would be the mobile home, the upper story would be constructed. She’s looking for three more bedrooms and second living room. She wants a spiral staircase put in, from the current living room to the new one she wants above it.
From looking at how it’s resting on the ground now (on cinder blocks at eight points–that must be where she got the number), I’d guess bars across the bottom in the same places would work.
Honestly, I don’t think it would look that bad (At least not the way I’m picturing it. The columns would appear simply to be unusually large porch posts), I just don’t know if it would be structurally possible. As for licensed engineers, she spoke with one before about building a conventional foundation under it and he quoted $25,000, so I really don’t think $100,000 will get very far unless something odd like her plan is done–at least not in this area.
There’re far stranger houses around here than what she’s planned. They appear largely homemade and quite rickety. How would these have gotten building permits? (What, exactly, are building permits? As I said, I know nothing about construction.)
For about $10,000 couldn’t she buy a used mobile home, put some money into ripping out/converting, and connecting the two? Maybe a small passage?
Alternatively, if she wants to stay on the same property, even a new double-size trailer should be well within her budget. Get rid of the old one.
Finally, still on the theme of getting rid of the existing trailer, she should be able to get a two story cape cod factory built home (modular as opposed to a trailer) built and installed for under $100,000.
Could a new house be built on the lot while the current trailer stays put?
I used to work for a company that designed bridges - the enginnering alone will cost a bunch - I can’t imagine anyone having stock plans for a trailer-on-a-shelf, and I doubt that the planning commission will rubber-stamp anything so bizarre.
By the time she’s done with the enginnering and the concrete work, she’ll have spent as much as a custom house completed to at least the exterior walls.
And, if the question of frost line vs. bedrock is still open, I suspect she hasn’t talked to anyone with any expertise in the field. (and no, I don’t know either)
It could be done, obviously. Given enough time and money, anything can be accomplished. The local zoning board would have to approve the “building”.
As others have said, it would be cheaper to rent storage and a small appartment (to live in during construction) and build a conventional structure. You may get a basement out of the whole deal too, for less.
Its an interesting idea, but I think youll find the cost will outway its niftyness.
This thing has custom written all over it and you pay a premium for custom engineering, building, materials, labor, etc.
I grew up spending a large amount of time in a neighbor’s house, which was basically a big amoeba.
They’d started with a trailer that had a nice big kitchen, breakfast bar, a decent sized bedroom, bathroom and fullsize tub/shower, and a back deck off of a wide sliding glass door. The deck wrapped around a doughboy pool.
The decision was made to expand around the trailer, using the side opposite the pool. Doing so conserved the existing kitchen and bathroom. They were able to save the money that they would’ve spent on a new kitchen and bathroom, and spend it on other things. They laid foundation alongside the trailer for a large living room and a large utility/laundry room. A ten foot wide panel of the trailer wall was cut away and sealed ( framed by 10x10 beams for added support) to serve as a door between the trailer’s small “living room” and the living room addition, along with a couple of steps down from trailer to addition.
Also, over the top of the trailer, they built a loft that served as storage and bunk sleeping for their three sons. You accessed the loft from a staircase in the laundry room half of the addition.
It was a pretty slick cusomization, and it served their needs for space on a tight budget quite well. No plumbing to mess with (aside from washer/dryer hookups) or purchase/installation of appliances (aside from a gas furnace, housed in the loft). Just some basic wiring and the construction.
Other issues, such as engineering, aside, it may be that there is no building permit system in place where she lives. In many parts of the USA, particularly rural areas, there are no codes or inspections required. Where I’m building all you need is a septic system that meets the requirements. There are no other inspections. Yes, you need a permit, but no structural or design codes.
If she’s really wedded to the upstairs/downstairs idea, it’d be a lot easier to just dig a hole, stick a trailer in it, fill in around it, and put another trailer on top. You could maybe set it perpendicular to keep the weight on the ground instead of the other trailer, which wouldn’t hold it.
The lot is about ten acres (it’s not been surveyed or anything like that, at least not in the memorable past). Not all of it is usable, a good chuck of it is protected wetlands and the rest is very heavily forested. I’d say two buildable acres.
Just to restate a third time (as many of you seem to be constantly missing this point): this is not two trailers, one atop the other. This is one “trailer” with a second story built onto it–you know, with wood and nails and such. Also, to make it clear this is not The Long, Long Trailer we’re talking about, which is why I’m hesitant to use the word–it conveys entirely the wrong image. It’s seventy feet long, the walls are made of wood and the roof is asphalt shingle. Moving it here required a very large truck, a crane, and closing the road.
Yes, a spiral staircase. I’m not sure why that’s surprising, with space at a premium, I’d say either a spiral or Dutch staircase would be the most logical, and with Dutch staircases being murder to climb, the choice seems already made. Plus there’s a number of places not too far from here that sell them.
There’s a modular home show this weekend in Augusta that I thought I’d check out, but to be such a rural and over-all poor state, things are incredibly expensive.
There are no apartments to be rent. The closest place that has apartments is Farmington and, being a university town, nearly all of them are single room and already taken.
“Utility connections” meaning what? The septic tank can’t be moved, it’s in the only area of the property that perks. Drinkable water is 150 feet down, drilling another well would cost a sizable amount. The power and phone lines could be moved, no problem there. There’s only one area with a southerly line of sight over the trees, so the satellite dish has got got be there.
She doesn’t want to leave for many reasons. There’s the family of beavers that live in the brook on the south side of the yard. There’s the family of the deer that live in the woods on the west side of the yard. There’s the monster of a moose that comes every autumn and stays either in the west woods or in the woods across the street. There’s the snapping turtle that lives in the brook and comes up every few years to lay eggs in the driveway. Then there’re the baby turtles that have to be picked up and taken to the brook lest the hawks eat them. There’re the raccoons that live in the east woods that come out at night and eat what seed the birds didn’t eat that day. There’re the squirrels that eat the cherries from the cherry trees and crabapples from the crabapple trees. There’re the field mice that run through the tall grass of the floodplain. There’re the frogs and toads and dragonflies in the pond’s cattails that eat the bugs.
Moving away from the constant company of the animals would take much adjustment.
Your big problem is the fact that there is no foundation. Once you start to talk about piers to support beams to carry a second story, you are talking enough enginnering and concrete work to build a very large conventional foundation - go see the modular homes, talk to someone who knows the geography - is that really bedrock, of a thin shale shelf just below ground?
Your current proposal is to essentially build a bridge 1 story high, and deck it with a house. The cost is in the height - building horizontal is always cheaper than building up.
Is there a wall in the existing structure which could be opened? I.e. put a new house right next to the existing structure, connect them, and maybe just leave the well and septic systems intact?
Once the new structure is complete, open the common wall - if you have 2 acres you should have another 20X70 chunck adjacent to the existing structure.
And as far as the permit process - maybe you wouldn’t need enginnered plans,
but how well would you sleep with several tons of concrete, wood, etc. sitting overhead WITHOUT knowing how well it will handle the next storm?
The existing structure is not on a foundation. The second one will have to be. The means the first structure will be floating in relation to the second one. Not good. Even if you ty walls together you could still get shifting and heaving and such from the first structure that is floating.
She would have to have a foundation put in under the first one to prevent that.
Or have very loose connecting points (expansion joints) between the two.
Ok, I’ve followed the dicussion for a while now and I think I can summarize things. Your mom won’t move and she is unwilling to change the existing layout of her property. She’s decided that building large concrete pillars to support “wood and nails and such” is the only option. You, apparently, agree.
We’ve heard a bit of discussion as to why this idea could be a problem. You’ve refuted most of them. It appears that you are simply looking for validation for her idea.
So, to answer your original question; yes, pillars could be built to hold a second story. I have no idea how much it would cost to build a structure like you describe. Contact a structural engineer for further details.
