Self levelling compound problem!

[flyingsparks]

Hi last night I used a latex self levelling compound on a concrete floor thought my kitchen dining room and hallway as I'm about to be laying a oak solid floor. The sub floor was fairly good but not level enough for the oak to go directly on to. This morning looking over it again there are lumps and bumps where I troweled the stuff and it didn't flow back flat again. This obviously dried hard now sO wonder what's the best thing to do? Is it Possible to sand or scrape off the lumpy bits? It's not megger bad just some areas which are not brilliant! Thanks for your help. Chris

 

[regsmyth]

Use an old saw to scrape off the high spots while it's still green.
Or the edge of a plastering trowel.

 

[flyingsparks]

Ok, looked at my floor a bit closer las night. It's worse than I thought. Not level got lots of trowel marks and ridges. Self levelling my Uranus.! I wonder if I could mix the levelling runny er. What I put down was mixed to the instructions but was a bit like treacle in consistency. Perhaps it could have been runnier? Does it matter if you make it too runny so long as any escape routes for it are blocked? Will it still set Ok? Tips on doing a better job appreciated.

 

[kjacko]

When i had my kitchen levelled. I didn't do it myself but watched the guy do it.
When it was dry there were the odd lump and bump.
I bought a really course sanding block specific for the job and it made short work of excess bumps.
Are you putting down any kind of underlay below your oak flooring?
If so, then once the big bumps are our the way surely the trowel marks won't make a difference?

edit:
http://www.tool-net.co.uk/p-348753/tool-net-20-grit.html?gclid=CI-gqZzjlLQCFU3HtAodoEwAgQ

 

[dazlight]

What screed did you use?
Some flow better then others. Also if you had used a spike roller while screeding then the floor would have a lot less bumps and trowel marks.
To rub floors down I use a rubbing down stone called a carbourundum stone.

 

[mac391]

If it was latex you should have got a bottle and a bag, the bag being the screed and the bottle the latex. If so it would have been pre gauged to the right consistency.. You still have to spread and level with a trowel anyway.

It's quite easy to rub down the day after !!

Have you tested for moisture content ? If not you are takeing a big risk fixing solid oak directly to concrete without a DPM (damp proof membrane)

 

[mattysupra]

as your fitting a solid i will presume you are fitting the correct way which is to glue it down?

There are only a couple of latex smoothing compounds that you can bond to.

You need a 25nm strength compound and above. Most latex products are around 6-16 nm so no where near suitable.

IF you can sand your screed down then it is not strong enough. Sadly the only fix is to remove it and use the correct compound. And NO, you cant just go over it with a better/ stronger compound.

If you have used the correct strength compound then it sounds like you will need to redo (over the top with correct primer)

DONT start to think the compound will smooth itself for you. A high quality one will help, but like applying plaster to a wall, it is a art to get it right.

PS, never change a compounds mix ration. Which make compound did you use?

 

[coolevilangel]

as your fitting a solid i will presume you are fitting the correct way which is to glue it down?

There are only a couple of latex smoothing compounds that you can bond to.

You need a 25nm strength compound and above. Most latex products are around 6-16 nm so no where near suitable.

IF you can sand your screed down then it is not strong enough. Sadly the only fix is to remove it and use the correct compound. And NO, you cant just go over it with a better/ stronger compound.

If you have used the correct strength compound then it sounds like you will need to redo (over the top with correct primer)

DONT start to think the compound will smooth itself for you. A high quality one will help, but like applying plaster to a wall, it is a art to get it right.

PS, never change a compounds mix ration. Which make compound did you use?

Good advise there Matty!

 

[flyingsparks]

as your fitting a solid i will presume you are fitting the correct way which is to glue it down?

There are only a couple of latex smoothing compounds that you can bond to.

You need a 25nm strength compound and above. Most latex products are around 6-16 nm so no where near suitable.

IF you can sand your screed down then it is not strong enough. Sadly the only fix is to remove it and use the correct compound. And NO, you cant just go over it with a better/ stronger compound.

If you have used the correct strength compound then it sounds like you will need to redo (over the top with correct primer)

DONT start to think the compound will smooth itself for you. A high quality one will help, but like applying plaster to a wall, it is a art to get it right.

PS, never change a compounds mix ration. Which make compound did you use?

Ah right ok. Tonight I went over with a 4m straight edge and marked the low spots and put more self leveller in those areas. I used ceMentone cempolay to start with first coat on the floor the other day and then tonight i used cempolatex 1 pack. The builders merchant didn't have any of the cempolay left but I was told this other stuff would be ok
On top of it.

The floor is now better in terms of level but does still need going over in a few areas of real big shallows. Is what I have done correct? I would then lay the dpm on top of this I assume? If I glue t he oak to the floor where does the dpm go surely you don't glue to the dpm?! What's wrong with floating it with a 3mm underlay, as per the instructions on the oak? Thanks for your help. Chris

 

[mattysupra]

a surface dpm as in a epoxy etc should go on the subfloor and then the compound on top. However, it can be applied to the surface of the compound if it is latex or acrylic based with a 25+ nm strength along with correct primer etc used.

Have you done it right? dont know¬! I dont know the product you have used and i cant see the subfloor.

As for floating solids, i have replied to your other post for you

If you want to float then use a engineered product. There really is no advantage of having a solid. both can be sanded etc, the solid thing is for some reason 'thought' to be better when it really isnt.