How do I find out what is causing my basement floor to crumble

Here's a link:

https://www.ehow.com/how_12166128_fix-crumbling-cement-floor.html

here is info, Sharon, about why this could be happening and you will need to call someone who does foundation work to check it out

https://www.myfoundationrepairs.com/foundation-crumbling-chipping-flaking/

Hi Sharon, often crumbling concrete is a sign of a moisture problem. I would contact a couple of contractors to get their advice about what the problem might be. Usually contractors will provide a free consulation in the hopes of getting work, so get two or three estimates and lilsen carefully to what they are saying and advising and think through if it makes sense. Also, you might check with neighbors to see if any of them have had a similar issue.

Take a look at your gutters and downspouts system, are they effectively moving the rainwater away from the house? Does your landscaping slope away from the house?

Moisture is the usual problem when concrete crumbles in a basement.

A product called Quikrete makes a patching compound for concrete, but first solve the water problem.

ref:https://www.moneypit.com/how-seal-crumbling-concrete-floor/

Usually it's a sign of a moisture problem. Heavy rains can raise the water table and the floor absorbs moisture. Starts to crack and peel. Hydrostatic pressure from underground water can actually seep into the basement thru the concrete. You can get a foundation company to look at the situation and give you recommendations. They should provide a free inspection. What you can do is take sheets of aluminum foil and tape them over the floor in a few spots with duct tape. Leave it for 24 hours. Then remove the foil and see if there is any moisture on it. If you do choose to coat the floor use a slurry of Portland cement. Pour it over the floor and spread it with a squeegee. It basically will level itself. Make sure the floor is clean.

Sounds like a moisture issue so you might check outside around the house and see if you have any pooling water, any downspouts too close to the foundation and the like. Once you fix the moisture, you can fix the basement.

This happened in my friends detached garage. William is correct, it is from water seeping thru. She cleaned out her garage and used the self leveling cement problem solved.

You have probably had some shifting with the supporting ground beneath and are now having some foundation issues. I would call a foundation company (or 3 for consistency) and get an review. They will give you an estimate and cause of problem. I had it done when I noticed a crack after living here quite a while,. They didn't charge anything and both companies said I had nothing to worry about, it appeared to be here for a long time. They also checked to see if the floors were level on the interior of the house. It gave me peace of mind.

Types and Causes of Concrete Deterioration

https://www.cement.org/docs/default-source/fc_concrete_technology/durability/is536-types-and-causes-of-concrete-deterioration.pdf?sfvrsn=4

You can check this comprehensive post about the certain causes https://www.hunker.com/13401272/what-causes-concrete-to-crumble

You have water under your foundation it needs to be sealed before the cement was put down

Here's a post that might help https://www.bobvila.com/articles/cracks-in-the-basement-floor/

Hello,

It could be Damp rising or too much sand in concrete mix. Call in a Builder to help. Get a few quotes to compare costs and time etc.

I agree with John, it sounds like it was an unsealed slab, and you have water rising into it causing spauling. https://www.youtube.com/watch?v=7PdsCptbGQ0

Do you have any obvious areas where moisture has begun to creep into the basement?