One way I've seen it done is with these.
http://www.strongtie.com/products/connectors/LSTHD-STHD.asp?source=holdttcat#gallery

A few years ago we had a tornado touch down near here.
It took a modular home right off the foundation and set it on the ground completely off the foundation intact a few feet behind it sitting flat on the ground.
It never even broke a window or hurt the shingles or the vinyl siding.
Right behind it was a 50' long garage. All that was left was a slab. The whole building and everything it disappeared.
Tools, boat and trailer ECT. gone.

 

Do those go into the foundation? These houses only have the sill plate bolted down, nothing is directly connected to the foundation. There must be something besides the weight of the house joining the sill to the house, no?

 

Depends on local code; https://www.dli.mn.gov/ccld/ManufacturedBulletinsFoundation.asp

Google the manufacturer....

Gary

 

My brothers modular home is bolted to the poured foundation in the conventional manner. Foundation guy was give a specific set of plans for the bolt locations. The house installer just craned the sections into place over the bolts.

 

That's how I assumed these were made until I started looking into it further. The sill plate was already on the foundation and bolted down before the houses were delivered. So they must have connected the plates to the bottom of the house somehow or just left them unattached. I can't see how that could have made it passed the local inspectors for four houses. :huh:

 

Looked in the basement and see no connections on the 10 foot section of rim joist that is visible. Looking at old pics, there are also no visible straps from the outside. I'm extremely confused.

 

They used wood screws, special screws, lag bolts, or nails- really need to read 1-13 (different builders with similar attachments), again; https://www.dli.mn.gov/ccld/ManufacturedBulletinsFoundation.asp

Gary

 

Gary, I'm looking at those, but they're not very clear to me. I see no ties or attachment plates of any kind. I imagine I would see a lag bolt or any big bolts. So I'm thinking they were just screwed, but where would the screws be? Diagonal through the rim joist into the sill? That doesn't sound strong enough. I appreciate the help.

 

Yes, they all pass code minimums. A normal stick framed floor has solid (or engineered) wood joists that are toe-nailed to the sill plate (which is bolted/nut/3"square washer- around here for seismic) and rim joist also toe-nailed; #23, 26; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_6_par013.htm?bu2=undefined

Page 9- "Floor Framing"
and pp. 24-- Fig.11; http://www.awc.org/pdf/WCD1-300.pdf

They leave the bottom rows of siding off to toe-nail, then add them- "Sill plate"; http://books.google.com/books?id=Kp...Q6AEwCTgU#v=onepage&q=attach new modular house to foundation sill plate&f=false

Gary

 

Thanks Gary, I guess that explains it. So they could do it from the outside as well and no fasteners would be visible from the inside?

 

You should see/feel some toe-nail ends of fasteners through the sides of the joists running perpendicular to the sill plate. The rims are fastened on the exterior, can't see those unless you are superman- or an alien that got your superpowers 25 years (and a 1/2 day) faster than superman from same planet.... lol.

Gary

 

None are visible on the 7 joists that are still exposed. The rim joist appears to be tripled up if that matters.

 

Perhaps the engineering page shows the detail of attachment, as it has been approved to meeting minimum code.

Gary

 

Not sure if your still interested. I had a mod installed on a superior wall basement in ny in 2014. The sill plate attached to the superior walls through carriage bolts. Then every 2 foot I believe is the distance was metal strips they go across the width of the sill plate I think they are 12 inches could be longer. After the house is dropped the metal strips are bent up and attached to the mod rim joist. That's why mods are missing the bottom two rows of siding when they are dropped. The strips prevent the house from being pushed in the wind and the weight keeps it on the foundation. That's why mods can be separated and moved by certain companies if they are 2 pieces. In high wind areas there are a few other things that have to be done to attach it to the foundation but the majority of the country that is how they are done unless there is higher building codes the international code.

Hope that helps. Also I saw the comment on the house being picked up and dropped. Some of the builders of mods tell you about the safety of them. As they are built to be moved and go down the highway at 55 without falling apart so whey are sometimes considered stronger then traditional homes for that reason.

 

I mentioned in the first post that the new houses on my block were using straps, but the old houses didn't. That's what made me question the whole thing. I'm thinking they may have used OSB that spanned from the sill plates that were bolted to the foundation to the rim joist. The sheathing on the house didn't go all the way down which left room to attach a strip of OSB. Don't know if that would be sufficient.