Need advice how to fix this mess: soil under the footings is soft

[rogerius]

We had the hole for the house foundation dug couple days ago and was a big surprised to see water coming out in the trenches. I say surprised because the house location is on top of the hill. Looks like there are a few small springs there, but really in top of the hill? The bad think is that the most of the soil which we found is sandy-clay and in contact with the water the lower trenche (walk out basement side) now is a pool of mud. The forecast call for more rain for next days so we are worry now.
We are thinking to clean the trenches by removing another foot of clay/mud and then add the geotextile and a foot of 3/4 compacted stone. Not sure if this is the best option so we are looking for any suggestion/advice. Below are couple picture of the mess...

Thank you.

 

[rustyshakelford]

Man on this kind of stuff I hate to say it but I'd consult with an engineer. Your talking the footing on your house. I wouldn't rely on the information gained here for something so simple. Need a box blade recommendation your at the right place but how to fix boggy soil your building on....nope.

Good luck, what a mess.

Brett

 

[rogerius]

Man on this kind of stuff I hate to say it but I'd consult with an engineer. Your talking the footing on your house. I wouldn't rely on the information gained here for something so simple. Need a box blade recommendation your at the right place but how to fix boggy soil your building on....nope.

Good luck, what a mess.

Brett

I know that "the specialist" is the best advice but I'm hoping for advice from members based on personal experience...

 

[Deere Dude]

We had the hole for the house foundation dug couple days ago and was a big surprised to see water coming out in the trenches. I say surprised because the house location is on top of the hill. Looks like there are a few small springs there, but really in top of the hill? The bad think is that the most of the soil which we found is sandy-clay and in contact with the water the lower trenche (walk out basement side) now is a pool of mud. The forecast call for more rain for next days so we are worry now.
We are thinking to clean the trenches by removing another foot of clay/mud and then add the geotextile and a foot of 3/4 compacted stone. Not sure if this is the best option so we are looking for any suggestion/advice. Below are couple picture of the mess...

Thank you.

I would do what you suggested. Pack good on virgin soil with a foot of crushed stone, thick footers with lots of rebar. You will have to wait for it to dry up though.

My last house was very near a pond, like 25' and the water table was almost to footing level. We just put the footings on virgin soil but no sooner than we did that it started raining a lot to where the footings were underwater by a few inches. We stuck a sump pump in to get the water down at least so the crushed stone gravel floor that was level with the top of the footers could be walked on. It dried out within a few days and we commenced to put blocks up. Never any problems after that in 12 years and don't expect any.

 

[EddieWalker]

You can build a house on just about anything, but at what cost? In some regards you are lucky to have caught it early and become aware that the soil there is not ideal for building a house. You can have an engineer design a foundation that will work, but in my experience, it's probably best to stop everything and rethink your entire plan for building your house there. Another thing to think about is insuring the house. If your insurance company finds out that you built your house over a known spring, will they accept a claim? If you are financing the construction of the house, will your bank allow you to build on that spring? Is it even legal to build on top of a spring there?

 

[Deere Dude]

We had a wet problem with our last house. It was 25' away from a high pond and the water table was at the footings almost. We put the footing in with just enough gravel to get everything level and poured the footing with 3 rebars embedded in the mix.

As soon as we poured the footers and they dried it started raining until the water level was above the top of the footings. I put a sump pump in the corner and got the level down so we could put crushed stone in for the concrete floor, which filled with water a time or two when the pump quit. Once it dried out a little to be able to walk around we commenced with the cement blocks.

We didn't have any problems after that and all was well for 12 years as long as we owned the house.

That is my experience with muddy clay and crappy soil under footings.

But, the safest answer would be to get an expert.

 

[rogerius]

Thanks all for advice. I called the architect couple minutes ago. He'll visit the site Monday morning with an engineer to take a look. He believes that the water which I'm seeing are not springs, they are just water pockets which are now draining after breaking the soil. Definitely I'll need to escavate deeper min. 12" and build a large pad of stoone under the footing to create a support and then beef-up the footing; looks like to build over the clay even if is dry is a no-no...

 

[RickB]

I know that "the specialist" is the best advice but I'm hoping for advice from members based on personal experience...

Nothing like amateur unverified and semi-anonymous advise.
That's what I'd look for when I need help with building my home.

 

[TomSeller]

Thanks all for advice. I called the architect couple minutes ago. He'll visit the site Monday morning with an engineer to take a look. He believes that the water which I'm seeing are not springs, they are just water pockets which are now draining after breaking the soil. Definitely I'll need to escavate deeper min. 12" and build a large pad of stoone under the footing to create a support and then beef-up the footing; looks like to build over the clay even if is dry is a no-no...

I guess you will know if it dries up, but remember this is not the wet season. Springs don't have to be in low areas, it depends on the geology. I walked away from buying a house when I found three sump pumps in the crawlspace. I asked about them I was told they were there because of the spring the house was built on. No thank you. That house sat on the market for years until they dropped the price.

 

[rogerius]

Nothing like amateur unverified and semi-anonymous advise.
That's what I'd look for when I need help with building my home.

Really appreciate if we can stick to the topic of this thread.
Thank you for understanding.

p.s.: Personally, I respect and appreciate any suggestion and advice from this community and not treat them as "amateur unverified and semi-anonymous advise" otherwise I'll not be here.

 

[rustyshakelford]

I gave my opinion because soils vary greatly from area to area, state to state and country to country. What would work here in Texas might've completely wrong for you in Canada with frost heave or whatever else you cold weather guys have to deal with!

Brett

 

[Oldoak]

You are certainly on the right track. Digging deeper and adding a foot of compacted#2 or even "pea" gravel. I would also add a loop of drain tile with an outlet leading to daylight. Definitely wouldn't hurt and much easier, at relatively little additional cost, to incorporate now rather than later.

This is basically what is done in preparation for setting prefabbed concrete walls for residential homes in my area.

 

[Loaderman22]

I'm in the residential building trade, & I'm glad you are having an engineer view it. Look at it this way, it may cost you a few hundred now, but if you do what they say & it fails, you can go after their insurance. Litigation is not the ideal scenario, but this is what they are trained for.

 

[boggen]

tossing rock under it all and going thicker and yada yada.

but how are you going to deal with "french drain" setup and the sump for the sump pump? do you have an area were you can run water further down hill than bottom of basement?

are you just going to deal with french drain setup on the outside? or also put something just on the inside of the footers to help pull any extra water out?

checkout basement "de watering systems" for already built homes. along with french drain setups.

========
also checkout different types of "water proofing" for the exterior of the basement sides that are below ground. from tars, to roofing liners / pond liner.

i am edgy about poured concrete walls with water proofer agent added to the concrete. there will still be some stuff sticking through wall most likely to hold the forms in place and set the thickness of the walls. the patch job after words may still be an issue of water coming into the basement.

i am edgy about "paint on water proofers" each type is different in how you PREP the concrete wall / concrete block wall. if you mess up the PREP the paint blisters and peels. read the directions and verify with manufacture. dust, to how long stuff has cured, to possibly mutric acid washing, to possibly some sort of primer may be needed. again water proofing paints all differ.

=========
general rule of thumb. only dig down as far as you need to never more. or have more issues of compaction/settling issues.

wet clay soil = slip n slide. if to wet it just gushes and does not really compact.

 

[RickB]

Really appreciate if we can stick to the topic of this thread.
Thank you for understanding.

p.s.: Personally, I respect and appreciate any suggestion and advice from this community and not treat them as "amateur unverified and semi-anonymous advise" otherwise I'll not be here.

My response is directed exactly at the topic of this thread. You solicited opinions. You have mine, like it or not.

 

[Streetcar]

Old oak made great suggestion with h daylighting pipe to drain current and future water

 

[Cord]

You can pour under water, but not on mud. If you over excavate, perhaps you could try pouring a mud slab? This is low strength concrete that doesn't have a structural strength, but is intended to provide a solid base for the structural concrete. Being concrete, it won't shift and settle like gravel which would be my concern it being under a footing. All you need is 2,000 psf (vs 4,000 psi for structural concrete) to provide residential bearing capacity. The mud slab doesn't need a particular thickness but it should be 2-3x the width of the footing. The big advantage is that once the concrete sets, you'll have a nice surface to set footing forms on top of. Often lean concrete is used for this purpose (600 psi), but I'd suggest using 3,500 psi concrete because the excess water will weaken it.

I will say that your photos don't show much for mud. The excavator would only need to scrape off a few inches to get to final grade. If this can be done the morning they start setting forms and can stay off the footing footprint you might be ok.

I agree, you are probably dealing with a perched water table. Because you have a walk-out basement, I'd suggest directing the drain tile to daylight so it can work continuously.

 

[quicksandfarmer]

A soil expert should be able to look at the soil and tell you if it is below the water table, seasonally inundated, or soil that is normally dry that happened to get wet. They have distinctive looks. Here, a septic field has to be in dry soil, a soils guy comes in for every installation and makes an assessment. They do it all the time and it's not expensive. I would think you're asking for trouble building a house in anything other than dry soil.

 

[Tractor Seabee]

These type problems are encountered here in the Puget Sound area often. The State and Counties are now getting gun shy of lawsuits when they approve a permit application and things go south. All new houses now have to have an engineered foundation sealed and signed by an engineer of record. Part of that is backed up with a geological data report and also addresses storm water runoff solutions and/or remediations. You are on the right track getting your architect in the act. I know architects who have decided you go back to school for engineering courses so they are more aware of site issues. Their license doesn't cover site engineering issues.

LOL, Ron

 

[Redlands Okie]

Several good idea presented so far. But your comment on a engineer showing up with the architect is your best bet. You need to pour on compacted or virgin soil in general. Gravel and drainage are good factors in general. No information if your pouring footings only or a concrete slab which if poured correctly can help spread the load. Footings on interior load bearing walls are a factor to keep in mind. Lots of rebar helps in general. As pointed out you can build almost anywhere. Heck homes are built on WATER that float on a concrete base. It's not a matter of IF it can be done, it's a matter of how to do it correctly and what is the cost. So hopefully the engineer knows his stuff. This may not be the web site to gamble your life savings on but it can be a great site for ideas and that seems to be what your after