Large Scale Central

Waterproofing concrete

Modeling
#1

For the MIK I plan to make a concrete/mortar base for the building. I am going to use the Ray Dunakin/Jim Rowson method of making a form adding rocks then back filling with concrete/mortar. The goal to be a solid concrete base with a stone facade both top and sides.

My question is this. How can the concrete base be protected, waterproofed, so it can remain outside without rotting? It will be on my bench work so drainage will be good and it really should remain relatively dry. It won’t be sitting in a puddle; but it will have dirt under and around it that will get wet and hold water like a sponge at least for awhile. I am going to likely bring the building in over winter but would like to leave the pad out if possible.

I considered using the same tar they use for sealing foundations. But I also don’t want to reinvent the wheel if people already have a good answer.

#2

use a mix of 1 to 4.
that is, what the germans used to build the bunkers in Normandy - and most of those are still standing strong. (the bunkers, not the germans)

#3

Devon, concrete likes water, it will not rot. However, because it likes water it has a tendency to absorb water and in our miniature world and your climate, that can be a serious problem. The freeze/thaw cycle will cause the concrete to crack and over time will destroy it. There are many concrete sealers on the market such as DryLok which is available at most big box stores or you might try flex seal (They claim it will waterproof anything). Regardless of sealers, it is not a seal it and forget it proposition. You should plan to reapply at least annually.

Just my thoughts.

#4

I never thought of actual clear concrete sealer for like walkways. Duh. I also have flex seal usually on hand. I think flex seal on the parts unseen and clear sealer on parts seen should do the trick. I wouldn’t even have issue with sealing it annually in the spring.

And just as you mentioned concrete does absorb water and with freeze/thaw I have had delicate concrete work “rot” or crumble away over time. Thick stuff isn’t an issue. And for this I’d rather be safe than sorry and do all I can to avoid it crumbling. I do plan to make it a couple inches thick so most likely would never ever be an issue. But a little preventive maintenance can’t be a bad thing. I’d rather apply it unnecessarily and have it last than omit it and run into a problem.

One of the reasons for leaving the base in place is to minimize its chances of cracking and breaking. The hope is to take the building in for the winter and then be able to come out in the spring and plop it on its base.

#5

I understand exactly what you are saying. Look at hydro electric dams. But we are also talking a couple inches of thickness over about 1 or 2 sq feet. Not feet thick concrete. If you go to Normandy I am sure there is some erosion and bits and parts flaking or crumbling off. When you are talking a 2 foot thick wall that is not meant to be aesthetically pleasing a little surface erosion or crumbling would go unnoticed.

I’d rather error on the side of adding an unnecessary sealer as opposed to not and having it absorb water and then crack over winter.

#6

what you are planning to do, is exactly the same, what in german is called “Waschbeton” (washed concrete), normally used for sidewalks, consisting of pebbles (washed clean on the surface) and two inches of concrete. sold in slabs between about 10" by 10" up to 1’ 8" by 1’ 8".
normally they crack only after some big truck roled over them.

go, risk a quick look:

https://www.google.com/search?q=Waschbeton&client=firefox-b-d&sca_esv=595776748&tbm=isch&sxsrf=AM9HkKlzYU679i5SvrkrZmNJ8PyEnHqAlw:1704404531399&source=lnms&sa=X&ved=2ahUKEwiV25bV2cSDAxX-qJUCHVGwCngQ_AUoAXoECAMQAw&biw=1264&bih=609&dpr=1.5

#7

I had a set of outdoor bridges made out of gypsum cement and found out with in the year that gypsum is a moderately soluble salt… aargh!

We brought some Quikrete Vinyl Cement back from the the USA on recommendations of Stoneworks, but haven’t started our concrete building oddessy yet, so can’t give any feedback.

And finally do you drink coffee and don’t have access to sea water and a volcano? This Aussie technique was recently discussed Coffee strengthens concrete.

…or when in Rome… MIT discovers self healing quality to ancient concretes

#8

Intermission time yet?

#9

We will be dead by then Dan !

Just saying?
:rooster:

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#10

I know roosters have a short life span, but I’m sure Devon was planning on being here a little longer :grin:

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#11

Now we gotta figure out how he has a concrete business and if he is just Joshing us ?

#12

Korm, we call that here in the US or at least here in N Idaho, exposed aggregate concrete. I did my front porch/steps with this method.

More or less that is exactly what I am looking to do. But with a different technique to expose the “aggregate”.

I fully agree that most likely this will not fall apart as I imagine it doing without sealing. It will be more or less as thick or thicker than a concrete stepping stone. I could easily make the top the same way I made the front porch but not sure how one would go about doing it in 3 dimensions. since you “expose” the aggregate while the concrete is still wet.

Anyway I don’t plan to reinvent the process. Ray, via Jim, has provided an excellent method for getting the look I want and with a relatively straight forward process. Its just a matter of “to seal, or not to seal. That is the question”.

I can say that sealing will be the last thing on my list as I am not sure how that will fit with the MIK budget.

Bill,

I found both those articles to be informative and made me go “hmm” because I do drink coffee and have access to lots of coffee grounds. I also live relatively close to Mt St Helens but alas decades later the volcanic ash is hard to come by. The coffee was intriguing right up to the part where they are refining it at 350 degrees C in the absence of oxygen. Not sure how I can easily pull that off.

I had actually heard that Roman “concrete” was self healing and that article was pretty interesting. I have a salt water aquarium so sea water is available once a week after water changes.

Rooster,

My holdings and business portfolio is so stinking diverse I was even unaware I owned a concrete business.

#13

I might just make it without sealing it and see how it goes. I can always make another one if it falls apart. I do agree with the majority that likely this will hold up just fine for as long as I will be around to see it. And as long as it isn’t moved I can see it cracking especially with a screen mesh reinforcing it.

#14

@Bruce_Chandler used a similar method for his stone mill which now resides on my railroad. I believe he left it outdoors year round, as have I since it arrived here around three years ago. I have it sitting on a concrete slab that is dressed with crushed stone and mulch around the edges.

So far, no issues.

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#15

Actually, I have access to both…