Thank you. The floor is about 12 year old. Does $3000 to clean and seal floors and wall for a 700 soft area sound reasonable?( For 2 coats of a water based epoxy seal. )Thanks in advance.
I am two decades past my experience with that. And my father and I did the work so I cannot judge cost to hire.
I don’t like the idea of a water based product to stop water. It could work fine, but I would search for competitive pricing.
I would spend $300 on a quality dehumidifier first and see if that solves your problem, it I had the basement.
I would follow Thackey’s recommendations with one exception. The other method prep the floor other than acid wash is to rent a diamond tip buffing wheel. It goes on a floor buffer typically used for removing and applying wax. This is what I did prior to having a professional 4 part epoxy applied. The diamond wheel removes about 1/16” of the concrete surface. This gives you the best surface prep so that the epoxy can adhere to the sanded surface. However, it is very messy and a respirator(not a nuisance mask) is a must. It also takes a lot of strength to handle the buffer when it starts across the floor. It was the toughest rental piece of equipment I have ever used, and I’ve used many.
$3.75 to $4.00/square foot sounds about right to apply an epoxy finish. If you are flexible with color it may save you if they have some material left over from a previous job. I had my kennel floor(130 sq ft) done for $500. I used a left over color. I had another bid for $800. Another for $1500. Make sure they put enough grit in the top seal coat so it is not slippery. Most of these companies will bid a two car garage for $2000-2500 to give you an idea. That is the bulk of their homeowner work.
After 12yrs your floor is about as cured as it's gonna get, and a good etching should suffice. The process would typically involve 3 cycles of > etch/rinse, etch/rinse, etch/rinse.
See the product's directions for acid %s, etc.
I've used the following on my own basement, and have been satisfied with the cost/benefit result.
It's a 1200 SF space, with moderate foot traffic and occasional furniture rearranging.
After etching (i use UGL Drylok Etch) is finished and the floor is *thoroughly* dry:
Two coats of a product called Epoxy-Seal, mfg. by SealKrete .. ~5 gal @ $35/gal
Followed by two coats of Clear-Seal, same mfg .. ~4 gal @ $30/gal (the clear coat goes further)
It's been 7 yrs since mine was applied, and still looks great, imho.
The few times something heavy/sharp has been dropped and caused a ding, I do a light spot sanding and the touchup applies/blends seamlessly.
With occasional ding maintenance, I can't see needing a do-over here for at least another 3ish years, and even that would only be as above: light sanding/color/clear.
A big caveat is that I wouldn't use SealKrete for a garage/shop floor .. there you're looking at a major materials expense for industrial duty epoxy.
But for your likely purposes, and assuming no environmental conditions out of the ordinary, it should prove satisfactory.
So for ~700 SF DIY: etching supplies $20, color coat $100, clear coat $100, misc cleaning brushes etc $30 = ~ $250 DIY +/- 20%