it is the concrete block wall of the foundation that is moving. The picture below is a mock up of where the piers are being suggested for the more expensive quote.

The previous exterior picture is from the left side of this graphic.

Thanks

Your best bet is to get a structural engineer there to see what is going on and make recommendations.

I came across quite a few jobs where 1k repair estimate needed 5k in work because things were overlooked or the lack of experience whoever priced the job... and 5k estimate needed under 1k of work for the same reasons.

As the price difference goes it could be many reasons. Some like to lowball jobs to get a foot in the door and make it up later... some have more experience and know what is involved they will cover every aspect of it, etc

But IMO structural engineer is the best bet to start with.

To make a very long story short of my 2 story garage foundation issue... free quotes said we had major settling issues (piers quote came in over 20k and others said tear down), but the person we PAID to come look said it was a drainage issue that caused the block issues. The structure was sound (minus fixing one corner). The person we paid didn't just look around, instead he was digging down to see where the footings were located and etc. He cost a little over $100 an hour, but he saved us so much money in the long run! I highly recommend getting an independent inspection.

Where are you located?

Please post an overall photo. From the first photo it looks like this was an addition? It looks like two different foundation types. It is normal to have movement if this is true. How long have you lived here. When did the movement occur?

What's the story with the strip of carpet on the second photo? The movement from the base trim and corner of the drywall looks minimal, but when was this room finished (painted?)

The problem with companies that make a living on installing piers is that they would recommend installing new piers if your problem was a roof leak, if they could get away with it.

Hire an independent engineer yourself for a professional opinion.

The post above carlos229 is not the OP.

One thing I was going to point out about the difference in cost: If you divide the total cost by the proposed # of piers, you get $1600/pier for one contractor and $1700 for the other. So their rate per pier is not far off at all. I did the same thing with foam jacking my sinking driveway. Had estimates from $980 all the way to $2200. Each estimated an amount of foam plus a per-pound price if they went over. I calculated the cost if everyone used the same amount as the highest estimate, and the estimates came out within a couple hundred bucks of each other at that point. So I picked the guy I liked best. He wasn't the cheapest one but it didn't make that much difference.

Question is how many piers you need, and I can't help with that. I liked the idea of hiring someone who has no stake in the game to tell you want you need.

There are multiple factors into deciding pier size and spacing. This mechanical engineering article discusses helical piers and factors to consider. I cant read how many feet your wall is to make an estimate, I am not thinking 3 piers alone is enough for the one wall, in my opinion, that is too long a span between piers for the concrete to handle. Soil compression and pier type/size are also a factors.

Here is another article with info on the process.