Posted: 4/20/2026 3:34:22 PM EDT
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I have a 125 year old house with a stone foundation and dirt floor. We get a little bit of water seeping in after rain events. I plan to pour concrete this summer and have dug out at least 75 buckets of soil so far to level the floor and plan to remove at least 50 more buckets to put in some tile lines under the concrete before I pour. There is a drain line that outlets by gravity so I do not need a pump but will have a sump where all of the drain lines meet to flow out the existing drain line. I also plan at least 2-3 inches of stone under the whole floor to aid with drainage. My question is, do I want to pour with fiberglass fibers in the concrete or should I use wire mesh? I also plan to seal the concrete with a garage floor type of sealer when done. The basement will be used as storage and a small workshop until I build the big workshop in a few years. |
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Use both! Seriously! About 15 years ago I was faced with a similar situation, an old barn with a dirt floor and a stone foundation. The contractor said fiber alone would be fine. He was very wrong. The resulting disaster saw the same contractor ripping up the floor and doing it over again just a month later when it cracked and heaved, in some places as much as six inches! Three years ago I built a new shop building. The concrete guy was ready to do mesh and rebar only. I asked for fiber as well (it's a very modest upcharge) and he had no problem with that. So far that floor is 100% perfect. The funny thing about the fiber is that, after about a week or two of curing, the fibers near the surface will poke up and the floor will be "furry", for lack of a better word. The solution to this is to get one of those propane weed burning torches and simply burn them off. One does have to be careful to remove or protect all flammable materials and to ensure good ventilation. You can try scraping the floor but that tends to simply all more fibers to be pulled up out of the surface of the concrete. Another thing I did wrong with the floor 15 years ago was not installing Sikaflex-1c-SL control joint sealant immediately. That let the control joints trap all kinds of nastiness. For the shop I filled the control joints about a week after the pour. They do not capture dirt, sweeping up is easy. Do not seal or cover the floor for at least a month or three, possibly more depending on the humidity level in the basement. You WILL get bubbles in your coatings (urethane sealer, epoxy, etc.). I waited three months and still wound up with sections of urethane sealer flaking. This problem is going away in two weeks when the flooring guys show up to polish my shop floor. Having a polished concrete floor is going to be glorious! And it's half the price per square foot of professional epoxy. Lastly, strongly consider erecting forms around your stone basement walls and encapsulating them in concrete. |
"Cogito, ergo armatum sum."
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Thanks for the info. I plan to pour 3-4' thick . I will definitely add the vapor barrier. Can I do control joints with a circular saw with a concrete blade and how far apart should the joints be? Should I be fine pouring right up to the stone foundation walls or should I install an expansion joint material where the wall and floor meet? https://www.lowes.com/pd/Reflex-Rubber-Concrete-Expansion-Joints-Common-0-5-in-x-4-in-x-60-in-Actual-0-4375-in-x-3-9-in-x-59-9-in/3365434?store=560&cm_mmc=shp-_-b-_-prd-_-bdm-_-ggl-_-LIA_BDM_000_PRO-_-3365434-_-local-_-21001912536-_-&gclsrc=aw.ds&gad_source=1&gad_campaignid=21001912536&gbraid=0AAAAAD2B2W9_LsQu_lvwkpX7mJr0xhwMt&gclid=CjwKCAjwwJzPBhBREiwAJfHRnWvIsvadXidcsmzzjMnPSL2Ye9EkC4xaihoe2oxbb1oilAP53rIdthoC6q4QAvD_BwE |
I would use expansion strips, wire, and fiber. gotta be sure  Sounding like a future "buried in the house" episode.  Pro tip: Don't let the feet stick up out of the floor. |
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Patriot
Q-Tard
“We’re surrounded. That simplifies the problem.” - Chesty Puller, USMC
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Good point on the expansion joints. Because the slab and walls will not be sitting on a common footer, it would probably be best to do this as a floating slab, with the expansion joint mechanically disconnecting the slab from the walls. I'd go 4" minimum. 6" would be better. You can use a circular saw to create the control joints, but it is difficult to maintain a straight, neat line. For control joint design guidelines just do an internet search for "concrete control joint spacing". |
"Cogito, ergo armatum sum."
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I just cut up my 1961 ranch homes concrete basement floor to re do some plumbing. There was no rebar or wire in it and has been perfectly fine all these years. It did crack but never moved, just hairline cracks. No expansion joints neither. I would do just mesh and vapor barrier. Then add the control cuts. You can cut them with a regular circular saw and concrete blade when the concrete is still under a day old. I did my slab last year maybe 8 hours after the pour. It just makes a hell of a mess with dust. I used a nice chunk of steel as a straight edge. I kind of held the bar and pushed the saw at the same time. I made very nice cuts that look like perfectly straight, the one cut is 40' long! I don't think I have ever seen expansion joint material in any modern basement since the temp swings should always be very minimal, but it wouldn't hurt, imo. |