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Gord Kurtenbach 07-10-2006 09:11 AM

self-leveling cement over osb boards
Does anyone have any advice concerning using self-leveling cement primer before applying self leveling cement? I didn't use the primer (duh!) and I"m about 1/2 thru doing my kitchen floor. I'm wondering if I should remove what I have done already and redo it with primer.

Here's the situation:

I'm installing radiant floor warming in our kitchen. The subfloor is dri-core over a cement slab. The radiant floor heating cable needs to be embedded in about 1/4 inch of self-leveling cement. I've screwed the dricore panels down tight to the slab so there's no flex at all. However, I'm concerned that the self-leveling cement won't bond very well to the OSB. The cement hasn't cured yet, but it doesn't seem to stick the OSB very well.

I'm going to finish the floor with engineered wood so it not like I have to worry about a super solid base to support tiles.

I'm just wondering I'm overly concerned and should just finish the rest with primer.

Any advice or experience?


pqglen 07-10-2006 05:23 PM

Self Leveling
I think you are overly concerned. I have used the self leveling with and without the primer. I use it every time I remember becuase it is recomended and seems to flow better with it down. It is not something I get to worked up about if I run out in the middle of a job. Self leveling will setup and stick to just about anything. If you check tomorow or the next day I am sure it will be bonded to your satisfaction. That stuff is a bit expensive to demo if you dont need to.

I am not from cold country (san diego ) I was wondering how the wood would hold up to the heat


Gord Kurtenbach 07-11-2006 07:53 AM

I think you are right. Today the cement is starting to cure and getting harder so it think it will be ok.

I did go out buy the primer for the rest of the job and its dead simple to use and my guess is that it is just acrylic, same as what gets added to mortar to make it stronger so it increases adhesion right at the surface.

> I am not from cold country (san diego ) I was wondering how the wood would hold up to the heat

A few years ago most radiant heating suppliers were saying "tile only" but recently both the heating and flooring suppliers say engineered wood floors are okay over radiant flooring. Floor warming system are pretty low power, for example, 15 watts per square foot so you can imagine that the 15 watt light bulb wouldn't be a lot of heat to put to a piece of wood, especially multiply wood flooring.

Also, I'm not *heating* the room with the floor system, it also has forced air. The radiant floor system is just to keep the draft off of the floor: one whole wall is a glass solarium so while its very well insulated glass its cools the surface of floor on wicked cold days. The solarium company recommended radiant floor warming as being a very nice to have with this arrangement.

thanks for the advice.


Square Eye 07-11-2006 01:15 PM

If you keep it at a fairly steady temperature, you shouldn't notice any problems.

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