Building on old double-wide site...smart or not-so-smart?

damselfish · October 21, 2015, 09:34:43 PM

First, let me thank you all for the great information that is on here. My husband and I used to read the board avidly, but stopped when we ended up buying land that already had a home on it.

Fast forward eight years, and we are thinking about building another home on the land as the first one has issues and would be hard to expand for various reasons.

There is a spot on our land where a double-wide used to be (the double-wide was repossessed before we bought). It appears to have a properly built up dirt pad, a flat concrete perimeter, and various flat concrete pads where the interior piers would have rested. It has its own electrical service and septic already in place and is in a good spot...short side facing south so maybe not so great for solar purposes, but a good spot other than that. There has been no obvious deterioration to the dirt pad or concrete in the last eight years.

We are considering building there, but we don't know how to evaluate what load the existing concrete will hold. I've done some googling and some searching on the forum hoping someone else has re-purposed a double wide site for a regular house, but haven't found any info.

Maybe the safe thing to do is throw up our hands and have someone come and bust out what's there and start over. I'd hate to do that, it seems wasteful. On the other hand, having a corner of a new house sink into the ground or something would also be pretty wasteful, right?

All thoughts welcomed!

DaveOrr · October 21, 2015, 09:44:12 PM

I would be worried that the foundation may not be up to snuff.
Are you in a frost zone?
What does code say about depth of footings?
You would be advised to dig down on the outside of the perimeter enough to inspect how deep the footings if any go down.

October 21, 2015, 10:21:45 PM

If they haven't heaved then they are deep enough for that site. If they aren't broken then they have potential. If you're still there then the soil is probably capable of supporting at least 2,000 lbs per square foot. How many square feet of footing is there and you have a rough bearing capacity.

rick91351 · October 21, 2015, 11:25:45 PM

Where is this located? Down south I think it might work..... Up north I almost bet that they would not allow it. Here bottom of the footing or footer is required at least 24" below the surface.

BTW what you bought is something I think anyone ought to be on the lookout for. Septic is in as well as the well and power and most likely the driveway. There is a bunch of $$$$ already taken care of.

However some of the mobile short cuts I have seen and heard about might be just best to rip it out and set the house the direction you want it.

damselfish · October 22, 2015, 09:25:35 AM

Thanks for all the replies. To answer some of the questions, we are indeed in a frost zone but not an extreme one. It is Southwest Missouri and the nearest large town (Springfield) has a code footing depth requirement of 18" so that is probably where we need to be.

There doesn't appear to be any frost heaving or cracking but we will re-check.

We will do some digging and measuring, may not be back to this thread for several days and then we will update, with some pics as well.

October 25, 2015, 09:02:38 PM

Well, my husband hit a concrete bottom edge only about 5 inches down. So it looks like pretty much a non-starter, I think.

We may have to consider having someone tear out that concrete then. I seem to have a general idea from googling it that concrete removal might be around $4 per sq ft plus dump fee.

rick91351 · October 25, 2015, 09:54:08 PM

Quote from: damselfish on October 25, 2015, 09:02:38 PM
Well, my husband hit a concrete bottom edge only about 5 inches down. So it looks like pretty much a non-starter, I think.

We may have to consider having someone tear out that concrete then. I seem to have a general idea from googling it that concrete removal might be around $4 per sq ft plus dump fee.

I would think that figure would be 'very light'. You would just have to get a couple bids when you get closer to build. I would guess a couple phone calls would put you more in the ball park. However there is no real hurry because I would not do anything until I was ready to build and was permitted. Then you would not be paying for the removal and then turning around and paying for the excavating for the proposed house when it could all be done in one trip or visit. Second thing the concrete can often be tore and and often used for fill and such. I have seen several jobs where old pieces of concrete have been used for walks and landscaping and look pretty attractive.......

Don_P · October 25, 2015, 10:33:38 PM

Is it cracked or heaved?

damselfish · October 27, 2015, 10:10:16 PM

There is no visible heaving (tilting). There are some cracks, maybe 1/4" across.

Here's a view looking across the pad to the south:

A straight-down shot of a typical section of the edge:

October 28, 2015, 12:06:38 AM

There is another reason just to leave it until ready to do something. What if you suddenly decided to find a double wide that size?

Don_P · October 28, 2015, 07:04:04 AM

Frost has no power without water. If the soil drains well then the footings really don't need to be below frost depth. It appears that is the case here. The next role of the footing is to spread the weight of the building out over enough area that the building doesn't sink, that is a judgment call but these seem to have proven they can hold a double wide.