Discussion on Mobile Home Piers & Tie-Downs

Repair help for the do-it-yourselfer.
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Posts: 11
Joined: Mon Dec 23, 2013 10:51 pm

Sun Dec 15, 2019 9:00 pm

I apologize in advance for the length and volume of questions here, but those involved here are pretty anal about getting things right from the get-go.

1989 Single Wide Mobile Home (64' x 14') complete rehab and overhaul down to the bones. I've researched and read everything I can find on this subject including the Mobile Home Repair Manual recommended here in the forum.

I've tried with no success to hire a professional MH mover to Level and Re-Secure the Tie-Downs for this MH. They are either retired, out of business, won't return phone calls or backed up 2-3 months. So we are doing it ourselves. Extensive remodeling experience, but this leveling thing is a first. We purchased the water level and are learning how to use it. We can get the bottle jacks we need. We removed all the underpinning and gutted most of the flooring. This allows us to literally stand between the joists on the ground beneath, giving easy access to the piers.

Piers - 7 concrete block piers on either side. The existing piers are concrete blocks (15 1/2"x15 1/2") with wood shims. Some piers have settled and shifted in huge ways. Some of the wood shims are rotted away or worked their way out. Some of the wood top plates are split, rotted etc.. Luckily no cracked or broken blocks.

I would be shocked to find 1 single pier that is level.
  • Should we simply level on the existing piers? My gut says to jack it up and rebuild the piers, to remove the sinking and shifting effect.
  • With that being said, should we try to pour a concrete foundation for the pier? Or has anyone used the plastic PIER PADS now available? Is there a better choice for the pier than the concrete blocks?
  • On the other hand, these piers have already settled.... some several inches.
  • Has anyone used the plastic shims that I have seen available? They look like a great alternative, but it also seems like they would not allow for minor adjustment by tapping on the end of the wedge.
  • And if not a single pier is level where would you suggest beginning? At 1 end? Or in the middle?
Tie-Downs - 6 tie-downs on either side. We are located in central NC. (Zone I) when reading the HUD requirements for tie-downs. The chart says says 2 vertical and 4 diagonal for each side. I assume that means 2 roof and 4 frame?? Not sure.
Here we are still struggling a bit. I understand the difference between vertical and diagonal tie-downs, roof and frame tie-downs. And the different types of anchors. With the interior walls and insulation removed in most places I can see that each and every tie-down goes to the roof. So these would be concealed roof tie-downs. I don't see any tie-downs attached to the frame. The roof tie-downs seem to be vertical although its hard to tell since 3 out of 12 are folded up, that means no connection to the ground and ground anchor is missing. But some do look like they were installed at an angle pointing out. The ground anchors that are left appear to be Auger or Drive anchors with the tension bolts. The tension bolts are so rusted, they would have to be soaked in PB Blaster (or similar) many times, over a long period and they still might break when moved.
  • Should we simply try to tighten the existing straps, replacing tension bolts if any break?
  • Everything I read says to tighten them till "taught". Well that seems to have quite a variable. I mean they are rated for loads in pounds. I would have imagined the recommendation of using a torque wrench. I can see someone easily over-tightening or under-tightening
  • Several anchors looked like they have worked their way loose. None are ground level.
    • How close to the ground should they be? Slightly elevated, or sitting on the top of the ground? If they should be sitting on top of the ground, then they all have worked their way loose.
    • Should we try to get them back into the ground? If they are drive anchors I assume a sledge hammer would drive them back in. If they are auger, what tool is used to turn them? How do we know the difference?
    • Or should we remove and replace?
  • I believe most of what I read said the roof tie-downs are normally installed as vertical. Is there any harm in them being installed diagonally?
  • Should we add frame tie-downs to the existing concealed roof tie-downs?
    • The HUD chart says 2 vertical and 3 diagonal. How should they be spaced?
We are intended to add 3/4" plywood flooring along with sheet-rock walls and sheet-rock ceilings. And then there will be the new roof and siding with plywood sheathing. In other words.... lots of added weight. So if we wanted to add perimeter blocking, now is the time!!!
  • Should we add additional piers? If so how to determine the numbers of, and placement of additional piers.
  • Would those metal adjustable piers suffice? What kind of base are they generally installed on? At one mobile home parts store carrying these, there are 4 different types of top plates in the way they connect to the mobile home. Regular, Saddle, Flat Top and Clamp-on
  • I believe these should all be under the perimeter rim joist. How do you add those without getting in the way of the underpinning? If it was a concrete pier, the rim joist would have to sit right on the edge. If it was a triangular adjustable jack on an ABS pad, part of the whole pad would extend past the perimeter of the MH. Doesn't make sense.

Lots of questions here... Looking forward to answers and comments. Thanks in advance.
I would still hire a professional if there was one.
One day I will learn to say, "NO."

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Posts: 5682
Joined: Wed Feb 28, 2007 8:01 pm
Location: Weedsport, NY

Mon Dec 16, 2019 7:06 pm

As long as you have things open, I would auger a below the frost line pier and pour concrete piers and use blocks on them. Mine are 18" dia. 9 each side. (80' home)
I would contact your codes officer and get their input before going much farther. It is much easier to work WITH them from the start than have to redo your work.
There are a few types of tie down systems out there. I have both the straps & 2 sets of bar style.

When you get to the point where you can get proper support under your home, use your water level. I found it is easiest to start in the middle and and call the first pier "0". Move from pier to pier and measure the +/- difference in relation to the first pier. go through all the piers and record the heights on a paper "map" so you can see what has to go where. Once you can see what you need start adding shims or blocks where you need them. The advantage to below frost line footers is that you probably will never have to relevel the home again.

Level the home BEFORE you start rebuilding the home otherwise everything you do will be off level.

Once everything is level do your tie downs.

"If I can't fix it, I can screw it up so bad no one else can either."

Posts: 242
Joined: Tue Feb 26, 2008 8:33 am
Location: Anna, Tx

Sun Dec 22, 2019 5:40 pm

If you have any plans to sell your place - now or in the near future - tie-down requirements have changed - and it impacts financing.

Google : FHA/VA Mobile Home Permanent Foundation Retrofit

I had a kit installed at all 4 corners when I re-leveled the last time. I believe only two diagonal are "required".
Opportunity has a shelf life.

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