Spackle with cement on concrete shell blocks

[Bengt_Salmose]

I have made a pool out of hollow blocks. Initially, I intended to plaster the inside and then add a liner, but the hollow blocks turned out so well that I'm skipping the plastering. However, I do want to fill primarily the seams between the blocks. The blocks seem a bit conical, narrower at the top, and some blocks are a bit crooked. I have sanded down what "sticks out," but there are still parts that need to be filled, about 0 to 1 mm, at most 2 mm in some places, and there are small gaps between the blocks sometimes. Previously, I used "ready-mixed cement filler" that hardens quickly, but I don't need that. So I tried in the pool's equipment room to use regular cement and a little water for filling. It works really well and is easier to apply than the ready-mixed filler and also much cheaper. I know that you're supposed to apply something softer than the substrate, and I assume that cement + water becomes harder than the concrete. Now, what I test-filled has been in place for more than a month, and I don't see any problems with it, but what happens over time and if it freezes, one might wonder. Does anyone have experience with this?

 

[jprahl]

I have built a pool using form blocks. Initially, I planned to plaster the inside and then install a liner, but the form blocks turned out so well that I decided to skip the plastering. However, I do want to fill the seams between the blocks. The blocks seem to be slightly tapered, narrower at the top, and some blocks are a bit crooked. I've sanded down the parts that "stick out," but there are still areas that need filling, roughly 0 to 1 mm, max 2 mm in some spots, and there are occasional gaps between the blocks.

Previously, I've used "ready-mixed cement filler" which hardens quickly, but I don't need that. So, I tried using regular cement with a bit of water in the pool's technical room. It works great, is easier to apply than ready-mixed filler, and is also much cheaper. I know that you're supposed to apply something softer than the base, and I suspect that cement + water becomes harder than the concrete. The area I tested has been like this for over a month, with no problems, but it makes you wonder about the long-term effects and if it freezes.

Does anyone have experience with this?

Hi,
I'm also building a pool with form blocks. How did your filling go?

 

[Bengt_Salmose]

What I filled inside the Pool with Heydi Express is presumably still there. It's covered with a liner so it's not possible to check. However, I realize that I probably didn't need to fill it because the unevenness of the pool walls wouldn't have been noticeable. The filling I did in the utility room, using cement + a little water, hasn't come off except in one spot where there's a slightly larger chip that has broken off, about the size of a hand and one centimeter thick, and I didn't fill that thickly. I suspect it's water that has seeped into the concrete and caused it to burst.