I really want to do a walkout basement over half the house and a crawlspace over the other half. Icf walls for the whole house.

Why is this apparently stupid? I've not seen basements at all in this area.

Im not 100% certain, but usually due to water table being too high and cost to install. Good choice on ICF!

jeremy said:

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I really want to do a walkout basement over half the house and a crawlspace over the other half. Icf walls for the whole house.

Why is this apparently stupid? I've not seen basements at all in this area.

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Rock is very shallow and fatty clay is very abundant as previously mentioned.

If you have a sloping lot, chances are the rock is only a few feet deep. If the slope is rocky without grass, then it's probably pretty close to the surface.

There are plenty of engineers who can design you a basement and contractors to build it, but the waterproofing is important due to the water table. I'm not sure how you would waterproof an ICF wall.

Typically a concrete wall is w/p with a rubberized bitumen product that is on a roll (example: mel-roll) that is adhered with an adhesive that is rolled on. On top of that typically goes a draiange mat then a french drain is placed at the base of the wall to daylight out if possible or to a sump pump system. Then the wall is backfilled with gravel.

Thanks for the replies!

I built my own log home with a 42 inch crawl space out of icfs, but I subcontracted the foundation part out.

I built a huge garage with icf walls and a slab in the middle. Again subcontracted that part out, but i convinced the contractor to let me help, so I was on the jobsite every day.

So, I will be building this house unless I find someone who seems knowledgeable and reasonably priced .

The build site has a good hill and I would love to do a walkout basement.

I was thinking what others suggested to mitigate water issues:

Water proof layers on the icf walls (i have seen some products) French drain, dehumidifier indoors, and thinking of sloping the basement slab with a drain in the middle of the floor incase of a flood. Long roof overhangs, and gutters.

I saw boulders on the land, but doesn't seem to be typical to see a lot of rocks. Soil seems to be sandy loam, so I anticipate good drainage. I'll do the excavation work for the basement, so rock doesn't bother me.

About an hour northwest of Fort Worth.


One concern is the water wells in the area are only 180 to 220 feet, so I think that means the water table is high. But, we'd be building on a hill that's at least 10 feet tall so I'm not sure if that helps enough.

I just love the log home with a crawlspace. I've gotten under there and added circuits, plumbing, etc and I love the flexibility. In the Texas area, I want a basement for tornadoes and the cheap square footage that to my knowledge wont get taxed.

I lived up in the Northeast for more than 30 years. There, having a basement is the norm. If it were me, I would just do a full walkout basement. It would eliminate the need for split foundation and would make it easier to address drainage issues, should they arise down the road. Trying to make repairs to the waterproofing/drainage on the exterior basement wall that abuts the crawlspace would be very challenging since that wall is basically underneath the house. If you plan to encapsulate the crawlspace, it would make repairs to the exterior of that wall nearly impossible.

As far as sloping the floor of the basement, I wouldn't do it. I wouldn't put a drain in the middle either. Instead, I use sump drains with pumps. I prefer that they be located next to exterior walls so that any water collected can be quickly pumped away from the foundation. Waiting until the water is already inside the basement isn't the best strategy.

I loved having my HVAC and water heater in the basement (so did the service technicians!). We did have a floor drain in that area that served many purposes, including AC condensate discharge and handling water heater service/leaks. That drain was tied to our sump which pumped out any collected water to a drain line in the yard. Worked perfectly.

Good luck with your build! Sounds like my kind of 'fun'!

Awesome advice! I hadn't thought of the issues of the crawlspace/basement split level.

Honestly, probably not a huge difference in cost to do the whole thing as a basement.

I love the sump pump idea, but may need to research that more and pick your brain to see how to do that. I love the idea of fixing the problem before water gets in, obviously!

I have a question for you. If my hill that I want to build on is roughly a 500 foot square at the top that slopes about 9 foot over another 300 foot, is that enough to do a walkout? Will I have tons of dirt work? I have a hard time with visualizing things like that in 3d.

Without more details, it is hard to say. However, you can get a good idea of the situation after you stake out the corners of the house on the property. If you see even a modest difference in elevation between the front and the rear, you should be fine. To avoid buying back-fill dirt, it is best to excavate enough soil for the basement so that you can back-fill around the front and the sides of the foundation during construction. You will want to excavate beyond the rear of the house so that water is always running away from all corners and sides of the foundation. This also allows you have a patio to step out on (and/or a modestly sloped backyard) to enjoy.

Once you have an idea of the elevation of the basement floor, you can then determine how high the first floor will be. Hopefully it is not too high relative to the street that it would necessitate a steep driveway. If you will have a garage, you can set the elevation of the floor of the garage a foot or two lower than that of the first floor… that will help with the steepness of the driveway minimal and avoid the need for lots of extra back-fill dirt.

Another aspect to think about are sewer lines. If you are planning to install your own septic, there's not much to worry about. However, if you are planning to tie into a municipal sewer line, then you need to know what its elevation is compared to your basement sewer lines. Ideally, you want your sewer line higher than the municipal line, otherwise you'll need a sewage pump system…I down think you will like that.

Of course, a good architect can help you figure all of this out.

It probably won't help much, but here are two pictures of the house we had built in Maryland in 1998 and sold in 2021. It should give you an visual example of the various elevations relative to the slope of the property.

Great info, thanks! I found a good elevation map and we have roughly 100' x 100' "peak" and we get a 10 foot drop nearly 150 foot away from that.

I'm doing more research, and learning lots. Thanks for the help!

I would consider that a very gentle slope. Your diagonal is only 4" longer than your run.

I agree, but think the slope is there with some dirt work. i.e. at least we have a drop. Would love to have a sharper drop, but it seems some dirt work should make it possible