Poured Cinder Foundation

hugheslar · 12-28-2010, 04:27 PM

I am a structural engineer with over 35 years construction experience. I recently ran across a type of foundation I have never seen before. The basement walls appear to be cinder block. However, upon closer inspection there are no joints or mortar. I know this because there are cracks through the 8" thick foundation wide enough to see the internal surface. Also, the interior parging is flaking off in large amounts to see joints if they existed. The cinder itself is crumbling to the touch. The house was built circa 1900. Could this be an early form of a poured foundation, or perhaps panels? I have tried researching, but to no aveal. Poured cinder concrete - really?

Ron6519 · 12-29-2010, 12:07 PM

Pictures would help.
Ron

jcardoc · 08-19-2011, 11:52 AM

I know exactly what you are talking about. My home was built in the early 1900s. My town was concieved thru the Pennsylvania Rail Raod. Therefore coal cinder was never is short supply. My foundation is crumbling pretty bad. It does not appear that there was ever any kind of 'binder' mixed in. Clinkers and some rocks. I dug up along one corner of the house all the way to the bottom and it is litterally falling apart. Former owners stuccoed it, and it just masked the problems. I am not sure what to do to repair it. I am thinking about forming it, and pouring concrete against it. I will have to do it in stages, because I am afraind it might blow thru the wall on the inside of the basement. Anyone have any better suggestions?

Ron6519 · 08-19-2011, 12:03 PM

Quote:

Originally Posted by jcardoc

I know exactly what you are talking about. My home was built in the early 1900s. My town was concieved thru the Pennsylvania Rail Raod. Therefore coal cinder was never is short supply. My foundation is crumbling pretty bad. It does not appear that there was ever any kind of 'binder' mixed in. Clinkers and some rocks. I dug up along one corner of the house all the way to the bottom and it is litterally falling apart. Former owners stuccoed it, and it just masked the problems. I am not sure what to do to repair it. I am thinking about forming it, and pouring concrete against it. I will have to do it in stages, because I am afraind it might blow thru the wall on the inside of the basement. Anyone have any better suggestions?

I'd start a new thread on this if I were you. It's dated and the original poster couldn't even bother coming back.

Aggie67 · 08-19-2011, 12:17 PM

I don't have much info to go by, but pouring up against it isn't high on my list. If you're going to dig it out to pour it, why not just replace it?

With that said, you should hook yourself up with an engineer who can check your soil out and put together a workable DIY plan for you.

Side note: I did a structural inspection this morning on house in PA that was built in 1905, and had a nightmare foundation. It looks like back in the 80's somebody tried to dig out crawl space and turn it into livable space, but got half way through the digging process, and gave up. Now all the soil is washing into the void and the rest of the basement from under the crawl space footings. Really bad scenario. Coal bin had 3 of feet coal in it from god knows when, though.

jcardoc · 08-19-2011, 01:28 PM

I wish I had the resources to just replace it. However, cribbing up the house and rebuilding the foundation isn't possible finacially.
I think I am going to brace the wall from the inside and pour against it from the outside. The bearing walls are about a foot thick. I am only going to do 8' sections at a time. I think if I mix the concrete a little heavy on the portland, and keep it pretty wet, it will soak into and adhere to the existing wall. I am going to do it in 2 steps. 1st pour will be up to grade, second pour will be from the sill plate down. I haven't been able to find any ifo on exactly how this type of foundation was originally constructed. There are other old homes in the area that do have the same type of foundation.

AGWhitehouse · 08-19-2011, 01:35 PM

Quote:

Originally Posted by jcardoc

I wish I had the resources to just replace it. However, cribbing up the house and rebuilding the foundation isn't possible finacially.
I think I am going to brace the wall from the inside and pour against it from the outside. The bearing walls are about a foot thick. I am only going to do 8' sections at a time. I think if I mix the concrete a little heavy on the portland, and keep it pretty wet, it will soak into and adhere to the existing wall. I am going to do it in 2 steps. 1st pour will be up to grade, second pour will be from the sill plate down. I haven't been able to find any ifo on exactly how this type of foundation was originally constructed. There are other old homes in the area that do have the same type of foundation.

If you are planning on pouring concrete in sections at a time then replace the whole foundation wall using an underpinning style method. Knock out 6-8 feet of existing wall at a time, supported by temp. wood framing and pour a section of concrete. Jump 16' down the wall and repeat. at 50% completion you'll have conc-cinder-conc-cinder looking walls. The last 50% will be removing what's left of the cinder, doweling the existing concrete and pouring the remaining wall. Won't be a whole lot more $, but will be a much better end result because in your proposed approach your home would remain bearing on the crumbling cinder.

jcardoc · 08-19-2011, 01:41 PM

I never thought of that approach. Thank you for the idea!

AGWhitehouse · 08-19-2011, 01:41 PM

.....

AGWhitehouse · 08-19-2011, 01:42 PM

This is a visual to my description. I would recommend this process be done by professionals to ensure structural stability throughout the phases.