Foundation Piering experience? Costs?

[HardDrive]

We have a corner of our house that has settled quite a bit in the past 60 years. We are going to have the area in front of our house torn up during a major remodel, and I was thinking it might be time to tackle the foundation issue. Its not moving much, but.....I'm neurotic and I want it dealt with.

The questions:

1) Can foundation piers be put in without heavy equipment? We have a very steep piece of property, the access to the front of the house is very narrow and 12 feet above the sidewalk below. Getting anything bigger than a Bobcat or a very small digger in here is not an option. Bottom of the foundation is at least 5-6 feet below the surface.

2) What is the cost per pier? I did a bit of research, and it looks like the piers go every 6 feet. Me thinks we would need 6-8.

3) I envisioned just stabalising things. We have plaster on the inside, stucco on the outside. I gotta imagine that trying to raise it is going to lead to some costly cracking or chunks falling off. Is this correct?

Any thoughts welcome. Thanks.

[ckissick]

I'm a geotechnical engineer, so tackling your problem is exactly what I do for a living. I wish I lived closer so I could take a look at it. Post some pics, and maybe PM me so we can discuss this over the phone. There's a lot to discuss.

But to answer what I can, yes, pier holes can be hand-dug on a steep slope. Jacking the house back up to level is recommended; just repair any cracking afterward.

You should do a floor-level survey to measure exactly how out of whack your floor is. To do so, follow these steps:
1) Make a map of your floor plan.
2) Buy about 50 feet of clear 1/4 inch flexible tubing. Tape one end along the lenth of a yard stick.
3) Get a 5-gallon bucket, Fill it with water about 3/4 full. Put it somewhere in the middle of the house.
4) Put the other end of the tube into the bucket of water, and suck on the tube until you get full siphon, with no air bubbles.
5) Now, if you hold the yard stick upright right next to the bucket, the water level inside the tube will be the same as in the bucket. Let's say it reads exactly 20 inches on the yard stick.
6) Start moving the yardstick/tube around the house and recording changes in the water level inside the tube, and map the readings on the floor plan. If the floor is perfectly level, it will always read 20 inches. If, however, the reading where you say the floor has settled reads 17 inches, the floor has dropped 3 inches in relation to the center of the house. (It could also read 23 inches, depending on which way the yardstick is set up - it doesn't matter.)
7) With all your data, you can construct a topo map of the floor. This will also help when it comes time to jack the floor up. Of course, you need to take into account differences in floor thickness, such as where you go from a hardwood floor to a carpet.

I can't quote costs from here. You need to call a local geotech company and have them take a look. But first, as I said, post some pics and PM me so I can guide you in the right direction.

[ckissick]

I'm a geotechnical engineer, so tackling your problem is exactly what I do for a living. I wish I lived closer so I could take a look at it. Post some pics, and maybe PM me so we can discuss this over the phone. There's a lot to discuss.

But to answer what I can, yes, pier holes can be hand-dug on a steep slope. Jacking the house back up to level is recommended; just repair any cracking afterward.

You should do a floor-level survey to measure exactly how out of whack your floor is. To do so, follow these steps:
1) Make a map of your floor plan.
2) Buy about 50 feet of clear 1/4 inch flexible tubing. Tape one end along the length of a yard stick.
3) Get a 5-gallon bucket, Fill it with water about 3/4 full. Put it somewhere in the middle of the house.
4) Put the other end of the tube into the bucket of water, and suck on the tube until you get full siphon, with no air bubbles.
5) Now, if you hold the yard stick upright right next to the bucket, the water level inside the tube will be the same as in the bucket. Let's say it reads exactly 20 inches on the yard stick.
6) Start moving the yardstick/tube around the house and recording changes in the water level inside the tube, and map the readings on the floor plan. If the floor is perfectly level, it will always read 20 inches. If, however, the reading where you say the floor has settled reads 17 inches, the floor has dropped 3 inches in relation to the center of the house. (It could also read 23 inches, depending on which way the yardstick is set up - it doesn't matter.)
7) With all your data, you can construct a topo map of the floor. This will also help when it comes time to jack the floor up. Of course, you need to take into account differences in floor thickness, such as where you go from a hardwood floor to a carpet.

I can't quote costs from here. You need to call a local geotech company and have them take a look. But first, as I said, post some pics and PM me so I can guide you in the right direction.

[ckissick]

Wow, my computer is really acting up. I was lucky to only post two times.

[HardDrive]

Thanks Charlie.

Wifes B-day today, and I won't have time to post photos till tomorrow.

[lm6y]

Glad you posted this. I'm looking at the same idea. I need to replace a few rotted joists, so I'm going to pier it while I'm there. I'm gonna cheat though. I'm ripping up the floors then digging the holes by hand. I'm going to follow this closely.

[dad911]

Hmmm... Not sure I would DIY without soil testing and an licensed, sealed engineering repair plan. Any obvious repair is going to raise red flags when you go to sell the house, and you will need the documentation then anyway.

[HardDrive]

Originally Posted by lm6y

Glad you posted this. I'm looking at the same idea. I need to replace a few rotted joists, so I'm going to pier it while I'm there. I'm gonna cheat though. I'm ripping up the floors then digging the holes by hand. I'm going to follow this closely.

I am still insanely busy, haven't taken the photos yet.

But THAT was actually where I was going with this whole post. Because outside access is so limited, and because we have a worthless 'concrete over dirt' floor that is not attached to the outside walls, I was thinking it would be WAY easier to take up the carpet, knock out the floor next to the foundation and place the piers from inside.

[lm6y]

This house is well over 100 years old, and was a three room mine shanty to begin with. Add that this side of town is a swamp, and you have rotting floor joists. Every house in this block has sandstone blocks under the center span joist. They sink over time.