Shortening cement piers in order to level house

[Will W]

I'm in northern Maine and am in the process of leveling my house (hopefully before the winter). It is supported on cement piers. Almost all are level, except for one corner of the house, which has risen 7". The piers around that one have also risen, although, not nearly as much. This is causing the rear of the house to lift and pivot at the roof, and unfortunately seperate at the sill.

I'm going to jack that corner of the house, shorten the pier in place, and then lower it back down.

As far as shortening the piers, I was going to try to create a fracture point by using my hammer drill with a 3/8 bit, and drilling around the circumference at the 7" mark. Maybe every 10 degrees or so. The holes would all intersect in the center. Then to make sure, I was going to score it with a diamond wheel. Then hopefully a gentle love tap with a hammer will seperate it.

Does this seem like a reasonable idea???

I'm taking preventative measures to make sure the piers no longer move after this.

[PeterD]

Have you addressed why these piers have lifted?

What is the diameter or shape of the pier?

I think I'd give serious consideration to having someone come in with a saw to cut them off. Probably be safer and easier in the long run...

[Will W]

quoted text -

There are 28 piers. They are all 1' in diameter, and they are spaced approx 10' apart. They are all cylindrical in shape. The problematic ones have been in a near constant pool/puddle of water in the weeks leading into the winter season. This has been happening for about twenty years. Over time the frost keeps pushing the column up a little each year.

I am taking affirmative action to prevent this in the future.

[Will W]

quoted text -

The more I think about it, I might try digging down beneath them, and hopefully lower them a little.

[dpb]

Will W wrote: ...[snip story of impressive case of frost heave]...

If you're going to the trouble of doing anything, my recommendation would be twofold --

1. Fix the drainage problem so the water doesn't pool at that corner
2. Fix the piers by resetting them at the proper depth for your area to combat frost heave.

When doing the later, there are newer techniques that tend to minimize the problem by forms which are slick so there's not a rough surface for the ground to "grab".

Being in an area which is neither so cold for such long periods nor wet, isn't nearly the issue here as in ME so don't have much (as in any) direct experience, but do recall a couple of articles in FHH over the last year or so. A search they could provide you some useful reading.

In all, I see very little to recommend the piecemeal solution you propose -- if a stop gap is the intent I'd probably simply take the one high one out and put in a temporary. For one year, can't be any worse than what you got (that is, even the surface isn't going to heave 7" in a year).

[dpb]

dpb wrote: ...

Sorry, that would be FHB...

[PeterD]

Personally, I don't like that idea... If you were to do that, I'd say rip the old ones out, dig new holes deeper and pour new (and larger?) piers as appropriate. I don't think the piers would be stable if you try to dig under then and drop them down.

[dpb]

As if they are now? :)

But the point is valid. There's no point whatsoever in stopgap measure that I can see other than simply removing the tall one and putting in the right sized one for the temporary. Rather than repeat, I'll reference my other response.