900 sq ft. . Douglas fir beams resting on rock cairns.
Cemented cairns. Cairns resting on surface.
100 yrs old. Some of the posts are just 3ft logs
Resting on rocks. House is level except corner
Where the post is undermined. 2 inches low in
Corner. Crawl space is enclosed with wood but
Mice get in.

1. What type of 20 ton bottle jacks and how many?

2. I want a cement footing around entire house
To keep mice out and cement/brick wall in places
Where snow builds up .
3. It is very damp in crawl space. Moldy and
Smelly. Should I open crawl space doors on hot
Summer days. I live in rainy vancouver.

20 Ton Low Profile Horizontal/Vertical Bottle Jack | Princess Auto

This is type of jack I was considering

 

20 ton is probably overkill but it certainly will do the job. Especially with older homes I like to jack from several locations to spread the load and strain instead of attempting to lift from only one location. Most often I use a handful of 2 & 5 ton jacks.

The problem with a 20 ton jack is finding a tiny spot underneath the house that can support 20 tons. Often I take 4x6 timbers below and run cross wise (6" being vertical) across the joists I want to lift and put two or three jacks along the length of the timber, usually only 3 or 4 feet apart because even a timber that size will flex too much under the weight of a house if you try to support it in one spot unless you're only trying to lift one or two joists.

If you want a cement footing under the whole house I would consider hiring a house moving company. Tell them what you want to do. They can come in and jack the entire house and leave it supported on cribbing. Then you can do all the footers and new foundation walls. When your work is done the house movers come back and lower it onto the new foundation. Considering the enormity of the task having a house jacked like that is pretty reasonably priced.

Especially if you will be working under the house I would open it up and maybe even have a blower shooing air under the house. It's not fun working in a wet or damp crawlspace. And the more damp the more insects you have jumping on you when you try to work. Before working don't forget to shine a light around underneath the entire space to insure that you are alone...

 

Thanks for the detailed answer. The joists are resting
On douglas fir logs so id be lifting log beams. I might
Build some piers out of cinder blocks and lift off them.
I guess I will work on one beam at a time with three
Five ton jacks four ft apart. Trial and error.

 

To do this right I agree with Dane.
The best way would be to have the whole house lifted.
Trying to pore a footing in sections, one at a time is a really bad idea.
Got some pictures?
This is not a great DIY job.

 

 

It looks like there has already been some jacking and posts added under there. Hire professionals to lift the whole thing. Doing it in sections may lead to settling as it's difficult to build a section of foundation wall under a house and have it support weight without lowering the house down onto it. You may find that you work on a section and that it's not supporting weight until you pull out the section next to it and the house flexes and settles down. Each section you do moves and sinks the house a bit more causing trouble with doors & windows sticking or not fitting, uneven floors and cracked walls. Far better to just have pro's raise the house and build a level, proper footer and foundation and set the house back down onto it.

 

6by6's are for front porch and side addition both of which need rebuilding.
Main foundation seems fine though the cairns seem primitive.

I just want a skirt that keeps mice out . Noise out. And doesnt mind snow
Piled against it for couple months in winter. Plus aesthetics.
Most of the weight of house is on the beams and skirt wont add much
To foundation.

 

Excluding the corner you say needs to be leveled, you don't have to raise the house just to install block underpinning. You can remove the wood/metal underpinning, dig and pour a footer, install your block and then fill/cover any gap at the top with wood or aluminum.

 

You could do a lot to dry out the crawl space by:

1. Installing rain gutters and downspouts (having 8' extensions), to carry water away from the foundation walls.

2. Correct the ground sloping towards the house to slope away from it (on the pictured side/corner), creating a gentle swale that carries water around the house instead of dumping it against the foundation. If you're in a high rainfall area, a French drain with perforated pipe just below grade in the swale will help immensely to move water before it gets to the foundation. With an outfall to daylight, of course.

 

Good advice, guys. The grading is bad. Anyway, appreciated!