Refinishing Concrete Floors - Difficulty, Options?

[simonucdd]

Hi. I’m a new poster here, only mildly handy, but trying to get some information about the feasibility of tackling the floors in my new apartment myself (in order to save some cash, and learn). It’s a brand new apartment in a mid-rise building in the Netherlands, and the floors are concrete. My first choice would be keep the concrete floors and have them finished, but the more I read about the process the more concerned I am about my ability to make this a DIY project.

From what I understand, the process is something like this:
1. The floors are (wet) sanded with a large, “stand-up” orbital sander
2. The excess water is removed with a shop/wet vac
3. The floors are “etched” with an acid solution to enable the finish to “grab” on to the surface
4. The acid solution is thoroughly rinsed, and the excess water removed with a shop/wet vac
5. A hard-wearing finish/sealer is applied (epoxy, acrylic, or polyurethane), probably two coats or more

It seems like a long and dirty process that requires renting tools (the sander, the vacuum) and working with toxic chemicals (I’m most wary of the acid); also, for an indoor job where there is no possibility of hosing things down after sanding/etching, I worry about all the excess water. I am also concerned that, never having used a large orbital sander before, I might gouge or leave grooves/orbital marks in the floor – a friend of mine used one of these sanders to do his floors, and they are full of large, circular marks.

Understanding that I don’t have any type of experience in this sort of work, don’t want to stain the floors (I like the concrete color), and am totally fine with an imperfect, industrial-type look, I have the following questions:

1. Is it possible to give the floors only a light sanding with a hand sander – or without a sanding at all?
2. Is the etching process absolutely necessary? I have read on a couple of sites that if the floors absorb water, they are likely already porous, and may not need to be etched. These floors definitely suck up any water that is put on them – but many people say the etching is essential in all cases.
3. Is it at all possible simply to put a couple of coats of sealer on the floor and call it a day – understanding that I’m willing to embrace the roughness and imperfection? Or is this just a recipe for disaster?

I will note that my other option is simply to paint them with a heavy-duty floor paint, and wonder if the sanding/etching would be necessary in this case also.

The floors are very, very dusty, and as noted, very porous (they suck up water like crazy). They are a bit rough, and have many imperfections (see the attached pictures), but appear to be level and without any cracks or major pitting.

The bids I’ve received for complete refinishing have been around 6500 Euros, which I just don’t want to spend. I’ve also gotten a much lower bid (approximately 1500 Euros) to cover the existing concrete with a concrete-like self-leveling compound, which is then sealed with some sort of acrylic – but obviously that’s not going to be the same as having the actual concrete visible. I could also simply call it day and cover everything with an inexpensive linoleum or laminate, but that would be my least favorite option.

Sorry about the length of this – but any and all input welcome. Thanks in advance!

 

[Ernesto]

Are you sure thats concrete and not lightweight concrete like gypcrete?

 

[simonucdd]

Are you sure thats concrete and not lightweight concrete like gypcrete?

Hi. No, I'm not at all sure - further proof of my inexperience. How would I know, and what would it mean in terms of refinishing?

Thanks.

 

[DarisMulkin]

Gypcrete is very soft. You should be able to gouge it with a nail.

Daris

 

[simonucdd]

Gypcrete is very soft. You should be able to gouge it with a nail.

Daris

OK. And if it is indeed gypcrete, does that mean that it's not something that can be "refinished" - that it would need something on top of it (like the self-leveling compound, for example)? Could it be painted - or would that still need some sort of more durable substance over the top?a

Thanks.

 

[Ernesto]

Sure looks like gypcrete from here. Maybe you could ask someone in the building.
If it is look up Ardex gypcrete topping/self leveler.

 

[simonucdd]

Sure looks like gypcrete from here. Maybe you could ask someone in the building.
If it is look up Ardex gypcrete topping/self leveler.

After the responses from Ernesto and DarisMulkin, I've been doing some googling - and I have the feeling that Ernesto may be correct, and that it might indeed by gypcrete. If so - from what I've learned from more googling - this surface cannot be used as the top surface, and must have something applied over it - unless you want lots of problems.

I've had one tradesman offer to cover it with a product called Egaline, which I would bet is close to the product you reference. Here's a video of it being applied:



I've also spoken with one of the guys at our local Home Depot-like store, and he swears it's an easy DIY project. But I'm not entirely confident in my abilities!

Thanks for the response.

 

[simonucdd]

Sure looks like gypcrete from here. Maybe you could ask someone in the building.
If it is look up Ardex gypcrete topping/self leveler.

After your first response, I did some googling - and I think you might be correct. Further googling led to numerous sites stating that gypcrete should not be used as a flooring itself, but needs to be covered with something - whether some sort of "top coat" of sturdier concrete, or tile or laminate or whatever.

I assume this is correct?

 

[simonucdd]

Sure looks like gypcrete from here. Maybe you could ask someone in the building.
If it is look up Ardex gypcrete topping/self leveler.

I found this video showing the application for a product called Egaline, which I'm assuming might be similar to the self-leveler you reference:



A tradesman who responded to one of my postings for floor refinishing offered to lay this down for about 20 Euros/m2. I also talked to one of the guys at our local Dutch version of Home Depot, and he said that this Egaline is super easy to work with, really does self-level, and can be done by any DIY-er without any special talents (unlike leveling "real" concrete). Doing it myself would surely cost less, but I'm still not sure it's a completely idiot-proof process. And I have been known to do idiotic things...

 

[Ernesto]

After your first response, I did some googling - and I think you might be correct. Further googling led to numerous sites stating that gypcrete should not be used as a flooring itself, but needs to be covered with something - whether some sort of "top coat" of sturdier concrete, or tile or laminate or whatever.

I assume this is correct?

Yes. The Ardex product you should use is Ardex SD-T. Probably should find a pro to do this and it requires the P-51 primer, http://www.ardexamericas.com/en-us/Products/substrate-subfloor-preparation-toppings/Pages/SDT.aspx

Here is the PDF on it http://www.ardexamericas.com/en-us/Documents/TechData_En_SDT.pdf

 

[Incognito]

I can confirm everything Ernesto says.

That's NOT concrete............per se, and therefore totally unsuitable for the treatment you've imagined. Any expert could form a more secure opinion ON SITE with a few rudimentary tests like scratching with a key or smacking it with a hammer.

Concrete will show very little response to a light hammer blow or key scratch test. Lightweight garbage.............well, when I see it most times it's already in such bad shape I don't need any testing whatsoever.

There are toppings that can create the effect you've mentioned. There are also cheaper alternatives.

 

[Floorist]

The gypcrete that I encounter is only 1 1/2" or 2 " thick. It is put over a plywood shelf. It is extremely unstable.

 

[simonucdd]

I can confirm everything Ernesto says.

That's NOT concrete............per se, and therefore totally unsuitable for the treatment you've imagined. Any expert could form a more secure opinion ON SITE with a few rudimentary tests like scratching with a key or smacking it with a hammer.

Concrete will show very little response to a light hammer blow or key scratch test. Lightweight garbage.............well, when I see it most times it's already in such bad shape I don't need any testing whatsoever.

There are toppings that can create the effect you've mentioned. There are also cheaper alternatives.

Thanks very much for the response. I submitted a response to Ernesto with some information about alternatives I've found to cover it, but for some reason the moderators have not approved it yet (probably because I included a YouTube link).

In short, there is a product in the Netherlands called Egaline, which is a self-leveling liquid that is often used over gypcrete. And this might be the route I have to take, unless I just want to use some basic lino or laminate - which I'd rather not!

If you have any specific names for the toppings and cheaper alternatives, I'd be super appreciative to hear about them - because they most likely have similar products in the Netherlands, prolly under different brand names. I am really trying to keep the budget down as much as possible. Thanks again.

 

[simonucdd]

The gypcrete that I encounter is only 1 1/2" or 2 " thick. It is put over a plywood shelf. It is extremely unstable.

Thanks for the response. Yes, this seems to be the consensus - I am going to have to cover the floor with something. Refinishing does not appear to be an option.

 

[Ernesto]

Thanks for the response. Yes, this seems to be the consensus - I am going to have to cover the floor with something. Refinishing does not appear to be an option.

Float some engineered hardwood over it!

 

[simonucdd]

Float some engineered hardwood over it!

No, that would be my last choice! Totally not the look I'm going for

 

[Ernesto]

I found this video showing the application for a product called Egaline, which I'm assuming might be similar to the self-leveler you reference:

https://www.youtube.com/watch?v=-sSCasqaI04

A tradesman who responded to one of my postings for floor refinishing offered to lay this down for about 20 Euros/m2. I also talked to one of the guys at our local Dutch version of Home Depot, and he said that this Egaline is super easy to work with, really does self-level, and can be done by any DIY-er without any special talents (unlike leveling "real" concrete). Doing it myself would surely cost less, but I'm still not sure it's a completely idiot-proof process. And I have been known to do idiotic things...

Not idiot proof but have several 5 gallon buckets ready and a nice mixer. As you can see in the video you can push it around fairly easy. Your looking for flat not necessarily level.
Now Ardex and this other make a gypsum based topping but that has to be covered with some type of flooring and not to be used as a walkable surface.
This one is the one or that manufacturers equivalent.
http://www.ardexamericas.com/en-us/D...ata_En_SDT.pdf

 

[Incognito]

Thanks very much for the response. I submitted a response to Ernesto with some information about alternatives I've found to cover it, but for some reason the moderators have not approved it yet (probably because I included a YouTube link).

In short, there is a product in the Netherlands called Egaline, which is a self-leveling liquid that is often used over gypcrete. And this might be the route I have to take, unless I just want to use some basic lino or laminate - which I'd rather not!

If you have any specific names for the toppings and cheaper alternatives, I'd be super appreciative to hear about them - because they most likely have similar products in the Netherlands, prolly under different brand names. I am really trying to keep the budget down as much as possible. Thanks again.

I can recommend Ardex products without any reservations. This is the kind of company you want to do business with. I don't handle the specific types of products that would serve your needs. If I needed to I would call my regional Ardex technical representative and then use his recommended products. They won't steer you wrong. Of course they're not a DISCOUNT brand. But what you're paying a premium for is a billion dollars+ of technology and experience and the best reputation I know of in this industry.

The fact that they are headquartered in an old steel industry town in Western Pennsylvania that just so happens to be the birthplace of my mom, dad, most of the grandparents, uncles, cousins........etc.

OK, maybe I'm a little biased. But I don't know of any comparable materials for substrate preparation with comparable integrity. Seriously, they are the best.

 

[simonucdd]

@Ernesto, @Incognito

Thanks very, very much for all of this information. I now feel I have enough knowledge to go forward and figure out the best way to tackle this floor.

This forum was a godsend - the information I got here probably saved me from making some stupid mistakes. Thanks again! Hope everyone has a good weekend.