whats the minimum / max depth levelling compound can go to?

[mickthetree]

Hi All

I have read the wiki and sticky posts, but I'm a little confused.

I have a slightly wavey concrete floor. it has a DPM and has been down for 20 years. The dips are max 5mm deep and I intended to prime then use self leveling compound. I am laying old pine floorboards over the top. Poss adhearing straight to the concrete or ply first, not decided yet.


Q1: Am I supossed to get enough to cover the entire floor so it creates one solid "top" over the concrete? If so if its 3mm at the thinest, its going to be 8mm at the thickest. Is that too thick? Should I fill 5mm dips first?

Question 2: I know you cant advertise on here, but can someone recommend a good make of compound (water based) and primer and where I can get it from? Maybe message me?

Thanks in advance

Paul

 

[mattysupra]

FBALL and you could go lets say 2mm and 7mm. The reason you try and lay a minimum 3mm is so it will flow. You will be o.k at 8mm with a good quality compound.

 

[mickthetree]

Cheers Matty

Really appreciate the advice

Paul

 

[mickthetree]

sorry, one last point, theres an old wooden door seal sunken into the floor (where the concrete was laid 20 or so years ago. The top of which is almost flush with the concrete.

Do I need to do something else over the top of this before I use a compound? or will I have to remove it and fill it first?

Cheers

Paul

 

[mattysupra]

if the wood is stable and smooth you maybe o.k to go over it, but without seeing it myself i would not like to say its o.k, any pics? Also there may be a break in your DPM where it is. This could cause problems. Really it should be taken out. You might want to use acrylic based compound instead of water based incase there is a DPM bridge in this area. ( water based is moister sensitive)

 

[mickthetree]

Hi Matty

I took it out as on closer inspection it was loose anyway.

It has left a gap 10" wide by 3" deep and there is no dpm in this section.

I have cleaned it all out and plan on putting a dpm in the gap and filling with concrete.

I guess I might still need to use acrylic based as you suggested and also wait for a few weeks for the concrete to dry out first?

 

[mattysupra]

i guessed as much. Can you send me a picture. (email or post on here) reason i want a pic is because there may be trouble ahead for you and we are better of sorting it out now before its to late! Also send a picture of the whole floor or at least where the new and old floors meet. If you cant email me through my profile then add me as a friend and then you will be able to.

 

[mickthetree]

Cheers Matty

I'll have to do it tomorrow as its a bit dark now, but I'll certainly do that. Really appreciate you taking the time.

Paul

 

[mickthetree]

Hi Matty

Here is a shot of the gap between the two rooms. as you can see there is no dpm in the gap. There is a part in the gap where it is higher than the rest as well.

http://www.flickr.com/photos/mickthetree/2699590846/

As I said, 3" deep and about 10" across. about 2m long too.

Any recommendations?

Thanks again

Paul

 

[mattysupra]

o.k. what we need to do is make one running dpm. You need to make the dpm from both floors connect together. If when folded down they are short then you need to put a piece of the same grade plastic down to bridge the gap between the two dpm's ( The plastic bit ) You then need to use a sutible waterproof tape to seal them together so they are air tight. (basically turning it into one running piece of plastic with no holes at all ) Even a pin hole in the plastic will give you a failed dpm, which we dont want as your new floor will fail !!! Next fill in the gap with concrete and smooth level as possible. You need to leave the concrete for a few weeks to dry. Next i would use (to be safe) an acrylic compound to smooth the floor. You can use water based ( easier to get smooth ) if you are happy to leave to dry for lets say 2 months! ( the new concrete section) AND MAKE SURE YOU PRIME BEFORE YOU LAY EITHER COMPOUND ! Problem should now be solved!

 

[mickthetree]

Great stuff. I'll get to work.

Thanks again for taking the time Matt.

I'll post an update when I'm done.

 

[mickthetree]

Hey matty

Tape to seal the dpms together. Can I use gaffer tape? or is there a special waterproof tape I should look out for? Somehting I can pick up on a sunday (diy store) would be good.

Cheers

Paul

 

[mattysupra]

there is a correct tape but i dont know where you can get it on a sunday! I guess a normal gaffer tape will do if it is water proof! You could run a bead of silicon between the sheets and then tape the edges to be safe?
just remember you need it air tight, one pin hole and the dpm wont work!