What to do with this exposed foundation?

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DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
Our house is all built on an uninsulated slab. I tell myself that there’s the benefit of cooler floors in the brutal Texas summer, but it‘s one of those things that’s always in the back (or front) of my mind as something that I wish I could do something about. Realistically there isn’t. Our house is also built on the back side of a hill, so while the front of the house has most of the slab buried, there are places on one of the sides and in the back where a lot of the slab is exposed. One of those has been bothering me a lot recently because it’s more visible than it used to be. (We used to have a large rain tank there, but we found over the years that the water that poured off the corner managed to overshoot it or undershoot it far more often than fill it. We moved the tank to a different location where we installed gutters and a downspout, and so now all this foundation is sitting with a lot of empty space in front of it.)

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We‘ve wondered about putting covered foam insulation on the egregiously exposed portions, but I think @peakbagger had such a bad experience with foam and ants that I thought it inadvisable. We haven’t had any carpenter ants that we know of, but we definitely have major fire ant issues in the land, thankfully not in the house. I don’t want to invite them in, and I don’t know if foam is an invitation.

I also love plants and gardening, and this is in our back yard that is not deer proof but is pretty deer resistant (if children don’t leave any of the four gates open). With the large rain tank now removed, I look at this space and imagine it much improved by plant life, and so I’ve been thinking of all sorts of options of what could grow well in that area.

My current thought is to build a cinder block raised bed in an L shape in the corner. It would take three layers to come up near the stucco, and we have lots of organic matter on the property that we could use as fill for the lower parts of such a deep bed. I’m wondering, though, what issues I would be creating by putting such a bed in that spot. Mostly I’m thinking of issues surrounding having to water the bed. Would we need to put something between the cinderblocks and the house foundation because of moisture? Or is that not an issue and it’s better to leave as little space as possible to provide better insulation? Can I hide foam panels behind a raised bed as a test to see if any ants try to nest in them?

Mainly I’m interested in the feasibility of putting a bed against the exposed slab, though if such as thing is reasonable, there will be gardening issues, too. The short wall faces south, the longer one west, so this area would absolutely bake in the summers, and I’m not sure if stuff would really grow there then. It would be more of a spring, fall, and winter bed, I think. I’d have to give it lots of water, and I know that the cinder blocks would wick that away. I do think that even cinder blocks with plants for some part of the year would be an improvement over what we‘ve got now.

I would be very grateful for feedback from those more knowledgeable than I about whether this idea of mine is worth pursuing. @begreen, any warnings, advice, alternate suggestions? @peakbagger, I’d love your input, too. Thanks for any knowledge and wisdom you can share.
 
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peakbagger

Minister of Fire
Jul 11, 2008
7,212
Northern NH
Dow does sell this product. II have considered using it to replace the foam on the two exterior walls that already have foam.

STYROFOAM™ BLUEGUARD™ Termite-resistant extruded polystyrene foam insulation specifically designed for insulating foundations in areas with termite activity. Contains deltamethrin insecticide, which protects the foam from termites and other wooddestroying insects. Insulation boards are available with square edges on all four sides or with shiplap edges on the long edges and square edges on board ends.
 

Bad LP

Minister of Fire
Nov 28, 2014
2,001
Northern Maine
The only issue with foam boards is they degrade in sunlight. You can build a planter bed keeping a 6” gap below your siding but it’s going to inhale water with such a hot exposure.
If it’s an esthetic issue there are fake stone veneer panels for various reasons like trailer skirts but they look cheesy IMO.
 

NickW

Minister of Fire
Oct 16, 2019
730
SE WI
I am going to install foam with an aggregate on it on an exposed foundation and framed walk out wall. Menards carries it from Styro Industries. Joints get silicone and loose aggregate applied. Expensive though...
 

EatenByLimestone

Minister of Fire
I remember getting in bed in TX and having fire ants in the bed. It wasn't a great experience. Be careful putting something up against the foundation.

I'd be worried about termites too.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
Dow does sell this product. II have considered using it to replace the foam on the two exterior walls that already have foam.

STYROFOAM™ BLUEGUARD™ Termite-resistant extruded polystyrene foam insulation specifically designed for insulating foundations in areas with termite activity. Contains deltamethrin insecticide, which protects the foam from termites and other wooddestroying insects. Insulation boards are available with square edges on all four sides or with shiplap edges on the long edges and square edges on board ends.

Thanks for the tip. I’m not sure about where to buy the product, though. Google searches seem to turn up information but no suppliers.

Do you have thoughts on the idea of putting a raised bed in that spot?
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
The only issue with foam boards is they degrade in sunlight. You can build a planter bed keeping a 6” gap below your siding but it’s going to inhale water with such a hot exposure.
If it’s an esthetic issue there are fake stone veneer panels for various reasons like trailer skirts but they look cheesy IMO.

Everything degrades here in the sunlight. It’s intense, and that spot does get a lot. I built my first garden fence in an area with full sunlight (even the Texas A and M website gives that advice). I learned quickly that that was a mistake. The next year my husband helped me dismantle everything, and we moved the fence and built raised beds where there would be more shade.

My objection to the exposed foundation is partially aesthetic, I suppose, but I don‘t think veneer panels would be an improvement, and we like our work to have more than one purpose. Probably many would have viewed our big rain tank as an eyesore, but it was almost beautiful to us when it was full of water. (It didn’t successfully catch water in that location, but we could successfully siphon water to it from the front tank because the back yard drops down so much in that spot.). I felt it served as a sort of moderating force for the temperatures in that corner, so I suppose I was wondering if I could build a raised bed there to act in a similar manner as something of a buffer and a place for me to grow more stuff (just probably not in midsummer. I even have to put shade cloth on my shaded garden.)

Will you elaborate on your recommendation to keep a 6 “ gap below the siding, please? In the front of our house our siding goes nearly to the ground (granted some of that ground is just rock), but some of it is soil and mulch from landscaping the previous owners did (rosemary and palm trees that may all just have been killed by cold). Is there a problem brewing there?
 
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DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
I am going to install foam with an aggregate on it on an exposed foundation and framed walk out wall. Menards carries it from Styro Industries. Joints get silicone and loose aggregate applied. Expensive though...

I think we may have looked at that very product, but we were still worried about the ant issue. In terms of cost, it would actually be cheaper for us just to build a cinder block raised bed. I hope it works well for you in your application. I’m sure it’s much more necessary in your heating climate.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
I remember getting in bed in TX and having fire ants in the bed. It wasn't a great experience. Be careful putting something up against the foundation.

I'd be worried about termites too.

The idea of fire ants in bed just makes me feel kind of sick. Actually, I have a couple of times gotten nauseated from experiencing numerous bites. They seem to swarm my feet before one takes the first bite, and then I’m tearing my shoes off and trying to clear them off. I really dislike them, but the dislike went to a whole new level when I discovered that they actually ate ears of my corn last year.

Is your caution about putting something against the foundation a caution just about foam, or does it also include the idea of putting cinderblocks there as a backing for a raised bed? We had figured wood would not be good in that location but thought concrete near concrete might be okay. The whole reason that I wrote this thread asking for advice was to learn from people before I make a big mistake. I‘d love to make the raised bed idea work but definitely not at the expense of problems for the house or the people inside it.
 

NickW

Minister of Fire
Oct 16, 2019
730
SE WI
So, I found the post that you were referring to of @peakbaggers... now I'm getting more concerned about my plans. Going to do some more considering about putting in some flashing. Certainly don't want the new cabin destroyed by carpenter ants.
 

EatenByLimestone

Minister of Fire
I had a large storage tub flipped over on the side of the foundation so it wouldn't collect rainwater. I was thinking about mosquitos. After the fireants in bed incident I went looking outside for the nest and ended up flipping over the tote. They'd built their nest up under it and it pretty much filled the entire thing up. The tote was like 3ft long, 1.5 feet wide. It was a huge nest. I dont know if they'd be attracted to the raised bed. But I made sure I kept the area around the foundation clear of things that could hide a nest after that.
 

Bad LP

Minister of Fire
Nov 28, 2014
2,001
Northern Maine
Will you elaborate on your recommendation to keep a 6 “ gap below the siding, please? In the front of our house our siding goes nearly to the ground (granted some of that ground is just rock), but some of it is soil and mulch from landscaping the previous owners did (rosemary and palm trees that may all just have been killed by cold). Is there a problem brewing there?

You want a 6" space between the soil and the house siding whenever possible to avoid build up of soils and mulches up to and against the siding where it will hold moisture and begin rotting the siding and sheathing that will result in rotten sills and studs. It will also provide a break any termite tunnels. Termites need moisture to survive and a tunnel baking in the sun will dry out AND be visible to the owner.

Of course this applies to the NE where I'm a lot more familiar with what's the normal practices.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
I had a large storage tub flipped over on the side of the foundation so it wouldn't collect rainwater. I was thinking about mosquitos. After the fireants in bed incident I went looking outside for the nest and ended up flipping over the tote. They'd built their nest up under it and it pretty much filled the entire thing up. The tote was like 3ft long, 1.5 feet wide. It was a huge nest. I dont know if they'd be attracted to the raised bed. But I made sure I kept the area around the foundation clear of things that could hide a nest after that.

Thanks for that explanation. I did have fire ants in one of my raised beds in my regular garden last year. Actually I have fire ants visiting all sorts of beds in the garden, but one nest did start outside the garden and come into one of the beds. They almost smothered a little eggplant after a rain. Thankfully I was able to use some outdoor plant stakes (borax type bait), and that took care of them.

I’ve never used the Amdro controls that fill our big box stores in the spring, but I am considering that maybe I should employ them on some areas where I know there are nests just so that we don’t end up with bigger problems in the future. They seem to like open, dry spots in our area, and after rain they build up their nests above the surface. After the snow and ice we had, we now can see a couple of nests (not so huge on the surface as what you describe, but who knows what’s underground?) near where we process our firewood. I had to step very carefully on Saturday when I was bringing branches to my husband to saw. I also saw the characteristic sandy piles on cracks in our driveway the other day.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
You want a 6" space between the soil and the house siding whenever possible to avoid build up of soils and mulches up to and against the siding where it will hold moisture and begin rotting the siding and sheathing that will result in rotten sills and studs. It will also provide a break any termite tunnels. Termites need moisture to survive and a tunnel baking in the sun will dry out AND be visible to the owner.

Of course this applies to the NE where I'm a lot more familiar with what's the normal practices.

Thanks for the reply. I walked around our entire house this morning peering at the level of soil and mulch, and some is closer than six inches, but it’s not building up or holding moisture. The climate is on the arid side here, and it is definitely different from what I was used to on the east coast.

One thing that really shocked me when I moved to this part of Texas is that gutters are pretty rare. People really don’t worry about moisture (no basements for it to seep into). I had my next shock, though, in the fall of 2018 when it rained and rained and rained and rained (about our average annual rainfall in the course of six weeks.) There was all sorts of flash flooding, but it was there for a few hours, and then it disappeared. I could go out one day after a “frog strangler“ storm, dig in the ground, and the soil would be dry. I still have a hard time processing that, and my husband and I have installed gutters on the lower roof portions of our home because we don’t want water pouring off there and collecting in front of our home. Installing gutters and large tanks has eliminated our flooding problems in storms we’ve had thus far, but we haven’t had the six-inches-in-one-night type since we finished. The area where I want to put this raised bed doesn’t have gutters, though, as the roof is so high there, we‘re unable to install or clean them. All that is to say that we’ll definitely be considering the moisture issue with regard to the foundation and the stucco.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
So, I found the post that you were referring to of @peakbaggers... now I'm getting more concerned about my plans. Going to do some more considering about putting in some flashing. Certainly don't want the new cabin destroyed by carpenter ants.

I wish you well in your considering. Maybe that product that @peakbagger referenced earlier would be helpful in your situation. Then, of course, you’d have to use mesh and stucco or some other covering, but more work up front (if you’re capable of it) should be worth it in the long run.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,256
South Puget Sound, WA
Given the heat level in that location, maybe a cactus garden? Agave?
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,310
Texas
Given the heat level in that location, maybe a cactus garden? Agave?

I saw this message right before I turned in for the night last night, and I woke up this morning thinking about agave. I had never seen them until I first visited this area in preparation for moving here, and I was immediately struck by what huge and elegant plants they are. A mature one would look great there (though I would have some concern about where rain water flows off the valley in the corner making it overwatered at times), Some time I need to get up closer to some to see how truly big they are. My kids call the flower stalk “giant asparagus” and think it looks like something out of a fairy tale. Sadly the agave pups that we had in our back yard didn’t make it through the recent freezing weather.

It did occur to me that this might be a good spot for growing roselle (hibiscus) if I can get my seeds to germinate. I’ve only made a small try once before, and it’s a good time to try again. Maybe I can sprout some the way I did my okra last year after you recommended it for corn.

@EatenByLimestone, I took my two younger kids on a walk today to go visit the neighborhood goat kids. While I was standing at the corner of the fence to pet the goat who was all eager for attention, I felt the familiar sting on my foot. I was wearing sandals. I jumped off the spot to the middle of the driveway, ripped off the shoe, and started brushing. It was only a few bites thankfully.
 

EatenByLimestone

Minister of Fire
I'm glad you got to them quickly! I'm pretty surprised that nothing has figured out how to eat fireants. It'd be a niche that desperately needs to be filled!
 

SpaceBus

Minister of Fire
Nov 18, 2018
6,886
Downeast Maine
We have a similar situation. Our house had thick EPS foam all the way around the slab and most of it had been infested by various types of ants, including a few carpenter ant nests (inside the house as well). Now there is no foam around the slab and it is noticeably colder in the winter. I haven't figured out what, if anything, I will do about it. Our siding does extend a bit over the edge of the slab, as does our flashing under the siding and housewrap. Sometimes I think this was a mistake because I'm not sure if we can retrofit slab insulation now without a lot of work. At the time we replaced the siding (along with many other repairs) we were too afraid to put anything other than 2" plus stone against the slab.
 

blades

Minister of Fire
Nov 23, 2008
3,738
WI, Leroy
there are foam types that the little buggers can't penetrate. Stuff machines like steel. I can not remember the name now. Not something you are going to find at any lumber or box store. very specialized. You hit a 6x6 block of this stuff with a full swing from 10# sledge and it just bounces off not even a dent in the surface. it is a military spec item.