Oiled concrete?

The new October issue of Dwell mentions a project using oiled concrete (p. 178) as a flooring option. Has anyone ever done this for a floor? What are the maintenance issues - residue carrying over to other floor treatments, how often do you oil, with what? etc.? I've seen concrete polished, stained, waxed, sealed, . . . and I've seen oiled soapstone counters, but never oiled concrete floors. I'm intrigued and need to know more! Thanks!

Ok, that's supposed to be page 178 - not sure why it did that!

Yes, I oiled mine using a combination of mineral spirits and RAW linseed oil, 2:1 It leaves no residue but it's a little stinky for a while. It defnitely waterproofs. If I leave an ice cube on the floor, the puddle will still be there the next day.
From what I've read, you pretty much never have to do it again, but ??
It darkened them somewhat and left no sheen or film.

I could not find raw linseed oil locally. I ordered it online.

do you have before and after photos?

how long did it smell for?

where did you learn about this treatment?

how long ago did you do your floor?

More questions for splatgirl:

I was doing some online research and:
1) from my readings, it seemed that boiled or raw linseed oil work equally well, why did you opt for raw?
2) one site said that linseed oil is food for mold/mildew so it is not a good choice for humid climates. Did you ever come across any discussion of this?

Other than this, it seems ridiculously simple and cheap.

Sorry for taking so long...

I oiled our lower level living spaces three or four months ago.
It smelled for maybe a week. It wasn't horrible but I was glad it was summer so I could have the house opened up. I used odorless mineral spirits.

I used raw linseed because that's what the research I had done suggested. I didn't ever read anything to suggest that boiled was either appropriate or inappropriate. From what I understand, the only difference is that the boiled version contains solvents and drying agents and I would assume this renders it quite a bit like the combination of raw linseed and mineral spirits anyway. Maybe someday I'll get around to experimenting with boiled to compare.

I didn't and don't worry about it being food for mold but yes, raw linseed oil, AKA flax oil, is edible (not the industrially manufacturered kind, however!). It's VARNISH once it's dried and seals the slab so well that if I've got enough of a moisture problem there to propagate mold in the first place, I've got much bigger issues than linseed oil could possibly be responsible for. There are plenty of people who will fly into a fit over having concrete floors in the first place because of the potential for mold, so choose your evil.

As I said, it seals the slab extremely well. A puddle of water on the floor will be there until it evaporates. This is absolutely not the case with the either of the two water based sealers I've tried. Water will eventually soak in with these and as a result take much longer to evaporate so in that respect, I think the linseed oil combination is safer.

I mopped on two or three coats and kept an eye out for any excess that didn't get absorbed so I could wipe it up, and that was that.
My experience is that it doesn't make the floors shiny at all but it does make them darker.
While I like the darker, I'm not crazy about the not shiny at all part. I think what I'm really looking for is something that will impart a nice even low gloss shine and then NOT SCUFF. So far I haven't found that yet but I still have our whole upstairs to experiment on!

Thanks for the great info. I also read that boiled is not a term that should be taken too literally but that boiled linseed oil will dry faster. But I also read that either one needs to be mixed with mineral spirits.

I just thought of two more questions.

1) how long did you wait after the concrete was poured to apply the oil?

2) how did you clean the slab prior to mopping on the oil?

Yea, boiled just means that there's other stuff in it from what I understand. If you can get a satisfactory result using boiled+ mineral spirits, go for it. It's certainly easier and cheaper to get.

I guess it was about a year between pouring the slab and oiling it, but I don't think that age would be an issue as long as you give it a couple of weeks. In fact, some sealers are actually dubbed curing agent, which concrete guys have told me is legit in that they do somehow help the slab cure to a harder, stronger product. By what mechanism this happens I have no idea, but I know that for as long as there is water avaliable, the curing reaction will continue. Maybe these are intended to be used shortly after pouring to seal in water?? Anyway, I don't see any of this really mattering for the purposes of a residential interior slab...

I just did a good scrubbing down with an industrial strength citrus based cleaner and water prior to sealing.

One of my concerns has always been the potential for a solvent based sealer (I'm thinking the heavy duty, commercial ones here that I don't like the idea of using indoors anyway) in some way damaging the PEX tubing in the floor. I'm not sure if this is warranted or not, but I don't want to take any chances with using something that would somehow degrade the PEX and cause mass failure down the road.

My two cents about the boiled versus raw oil.......my husband and I used boiled and had a very sticky mess the next day after the application. We put way too much on in the first place with the thought that the majority of it would sink in but that was not the case. I do not know if raw would have made a difference, so just be advised to be prepared to wipe off any excess, because it doesn't seem to ever fully dry if left in a thick coating.
For some reason, I suppose for shine, we put floor wax over top and it has turned splotchy (dull in spots) because of moisture that migrates upward through the slab when it rains. Oddly enough, before it rains. It has something to do with barometric pressure, i suppose. The fact that there is water under the slab is a whole different subject. We don't have all of our gutters on, grading not complete, blah, blah, blah.
As for mold growth, I think we are seeing some small patches of white powdery mold forming in some dark areas (under the sofa) of the room, so there is merit to that concern.
Don't mean to scare you off.......we have slab on grade in the mountains of NC where we get plenty of rain. We could not find much information on the finishing techniques pictured eveywhere so we had to wing it. There's always a down side to experimenting.

One reason why you may have had a sticky mess the next day is that you have to dilute linseed with mineral spirits or some othe type of solvent. The solvent is what allows the concrete to absorb all the oil. With out the solvent the oil will creat a hard outer shell that will eventaully allow moisture to penetrate. With the solvent the oil penetrates deep into the concrete and seals in three dimensions. I would start out with a 2:1 ratio of solvent to oil. After the mixture is appplied to the floor it should take no more than a half hour to dry. If it takes longer, then you need to add more solvent. You should put down a few coats.

splatgirl, do you find that this finish scuffs?

where did you learn about it?

jamie

Hi Splatgirl

I made a concrete counter I would like a little darker but I too am concerned about having a nice sheen. Did you find something that worked on top of the oil. The concrete is only next to the sink and there are other surfaces for food prep but I suppose toxicity is still an issue in a kitchen.

Thanks, Andy

I wouldn't try to apply a water based sealer after oiling if that's your question. My experience has been that oiling does not leave any appreciable sheen or gloss. If anything, it makes the sheen of the surface LESS consistent.

For counter tops (or floors, for that matter), either oil them OR use a water based sealer, not both. Once it's been oiled, it can't absorb anything and water based sealer probably isn't going to look or work right.
If you haven't done either and want the counterotps darker, I guess I'd try a non-toxic pigment (IE watercolor or tempera paint) mixed with water and allowed to soak in and saturate the concrete. Rinse off whatever pigment remains on the surface after it's dry and then seal. No idea if this would work...just a guess. There are also stains for concrete but AFIK, not intended for countertops and not necessairly non-toxic.

[quote:splatgirl format=text/plain]

One of my concerns has always been the potential for a solvent based sealer (I'm thinking the heavy duty, commercial ones here that I don't like the idea of using indoors anyway) in some way damaging the PEX tubing in the floor. I'm not sure if this is warranted or not, but I don't want to take any chances with using something that would somehow degrade the PEX and cause mass failure down the road.
[/quote]

I wouldn't worry about this. Polyethylene is one of the most chemically resistant plastics (they use it for gas cans). The crosslinked stuff is even more so.