Bonded screed over self leveller

Discussion in 'Builders' Talk' started by David Moxon, Sep 19, 2019.

  1. David Moxon

    David Moxon New Member

    I put down a layer of self levelling compound but have since measured and realised my floors are out of level. To rectify this I need to bring the floor level up. Some of this can be done using a modified bonded screed (over 15mm), and some will need additional self-leveller (under 15mm).

    My question is how do I ensure the new screed and self leveller bonds with my existing self leveller that is already laid down?

    I don’t have the kind of money to hire a proper scabbler which I’m guessing would be the correct thing to do? I have sanded it down but I’m not convinced this has made a difference.

    I do have an SDS max breaker at my disposal so one option is to try and dig out the existing leveller, but I’m trying to find a solution that doesn’t need me to do that as it will be a lot of work!

    Any advice?
  2. DIYDave.

    DIYDave. Screwfix Select

    SBR Slurry coat perfect for this - will aid adhesion between layers

    SBR mixed with dry cement powder to form a thickish, brushable coat then paint over floor, allow to go tacky then pour next batch

    How long has the SL been down for though ?

    Might not actually be required as when pouring SL in batches to make up more than max pour level, once 1st layer is cured, you wack on next layer over the top - no bonding coat in-between

    Give the tech department a call at your SL choice and check with them

    No point in wasting time and materials if not required
  3. David Moxon

    David Moxon New Member

    Great, thanks!

    I was planning on putting a bonding slurry down anyway, so hopefully this will be enough. I’m using Ardex A35 cement as it’s a thin screed, and their P51 primer to produce the slurry. I’m assuming this will be the same as an SBR slurry.

    SL has been down for about 2 weeks. I will call the retailer to see if they can help too.

  4. Richard_

    Richard_ Active Member

    You can get levellers that go up to 40mm. They tend to be a bit thicker, more self smoothing than levelling. You just need to help them level with a straight edge.

    I use Mira X Plan, a local supplier sells it at £13 a bag inc VAT.

    A decent specialist supplier will be able to advise you what (if?) a primer is required. They're also good at advising on workability for your application... and your skill level!

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