My wife and I recently purchased a 1920’s Bungalow. The home was redone but for the life of me I can not figure out why contractor did not redo the floors. The floors are original to the house and are separated, cracked and I find my furniture needs to be leveled because the floors are uneven and warped. Three questions:

The unevenness of the floors; the floor dips in areas and is uneven. What caused this?
How big of a job is it to pull up the old flooring and lay down new?
Obviously it will take a floor contractor. Any idea on cost per sq. ft

It will vary from area to area. I can only tell you what I am getting in my town. you will be looking at $7.75 per sf. to tear out, level and install new flooring. Then there is material at $4-5 per s.f. and finishing at $5.75 - $6.25 per s.f.

I know there are guys who do work for less. But I use a dustless system and try to offer premium service and charge accordingly.

Most flooring pros give free estimates. Your old floor MAY be repairable. And if so, a better option than total replacement. But only a qualified professional can make that determination. Get at least three opinions.

This might not make a differnce, but I think it can add value to save old features of a house.

If it ends up costing the same, or maybe even a little more, having the original 20's flooring brought back to life will be plus. People love vintage and periord correct details, especially when it comes time to re-selling old houses.

But somethimes you have to start over if the flooring is so badly damaged. It sounds like your floors are in pretty poor shape and you might not be able to save them.

The floors dip in areas and is uneven,What causes this?
Not surprised for a 1920 construction.

How big of a job is it to pull up and lay down new?
It's a huge job,you're not just talking about replacing the wood floor,but also leveling the subfloor..

Any idea on cost per sq ft?
Well you'll have to factor in the prep work along with(tear out and preparing the sub floor)plus the install and sand & finish price..
Are those floors in such bad shape that they can't be resanded and finished?

QualityFloorCo must have been a politician in a past life. He answered all your questions without saying anything, lol.

The irregularities in the flatness are caused primarily by settling of the house over the years, joists warping somewhat as they dry out, and other things related to the age of the house. It is unlikely that you will be able to correct this without removing the hardwood; but you could try to shim from underneath, provided you have no finished ceiling. It is usually more cost effective to remove the hardwood, sand down high areas, pack low areas, refasten the sub-floor. I generally also try to convince the home-owner to have us install new plywood underlay as well, since the old floor boards are very dry now and have lost a great deal of their nail holding capability.

A break-down of costing based on our company's pricing structure:

1: remove and dispose of existing hardwood: $2.00 per sq. ft.
2: general leveling and re-fastening: $1.50 (allowance)
3: install new plywood underlay (3/8th inch): $2.50
4: supply (3/4 by 3 1/4 select and better grade red oak as an example), install, and finish (brown stain plus 4 cts commercial water-base finish : $10.00 - $11.00 depending on scope of work.

Hope this helps.