Self Leveling compound question

[idoc4u]

Can anyone tell me if it is necessary to use a primer before applying a self leveling mortar mix to a basement slab floor?

Thank you!

[jadnashua]

Please read the instructions! All SLC's that I'm familiar with require the primer. SOme even have different ones depending on the surface, or if the same, different requirements on application of the primer. One of the biggest mistakes people make with slc is not believing the set time...depending on the temperature and the version you select, you can have as little as 10-minutes before things start setting. At that point, you can't do anything. Another mistake is that people don't use enough. It works much better if you make the pour deeper than you think you need. Check out www.johnbridge.com to get some help on this.

[gregs1]

I would play around with it first getting the feel. I put some on wood, and the mix was too thick, and did NOT self level at all.
i had to quickly do it by hand.

[idoc4u]

I wasn't sure if I would need to put primer on my slab floor prior to the application of the leveling compound. I will essentially be pouring leveler over a slab, it didn't seem necessary to prime.

[jadnashua]

The primer is a bonding agent. Unless the manufacturer says you don't need it, you always need it. The slab should be clean first, too...no dust, dirt, etc. prior to applying the primer.

Keep in mind the open time you have (say 10-minutes to 30-minutes depending on the configuration) is the time from when the stuff touches the water until it starts to harden. So, the clock starts once you pour it into the water to mix, and that should not be short-changed (typically about 3-minutes).

You must be exact in your water measurement. SOme of the pails, etc. that are marked out are NOT accurate enough. If you have a choice, start with cold water, it may give you an extra few minutes. And, you must mix with an appropriate paddle at the specified speed for the indicated time. This is a special mix, and the whole texture will change once everything is mixed well - it can appear to be two differnt substances if you compare one mixed well verses one that was not mixed long enough or not at the right speed. Don't even think of trying to mix it without a good 1/2" drill...you'll burn out the motor otherwise. Some of the brands flow better than others. Think thin pancake batter, not crepe batter. You need to move it to create a wet edge, or it will have an edge like a pancake. If you get the whole area wet with the stuff AND you have enough of it, it will level itself. It's not water. Goes back to my comment that most people don't use enough. Over a slab, you can feather edge the stuff, but you don't have much time. It's easier to flood the area, make sure every part is wet with the stuff, and you've got enough to fill in all of the depressions, and enough to cover the high points, or it will act like a coat of paint, and leave the high spot high with a thin coat on top. And, you need to do it all fast! Unless you are doing one depression, you need help, or you'll get in over your head. Measure out the water in advance so you can just pour and mix, pour and mix with someone else seeing to getting it onto the floor and cleaned up. It's not bad if you understand, but you'll create a big, hard, mess if you don't!