Screed sanding advice

Discussion in 'Subfloor Preparation' started by Kilojade, Nov 23, 2022.

  1. Kilojade

    Kilojade Member

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    Hi guys. I am having a 50mm thermo screed put down this week. I have been told I need to sand/grind the laitence off 4-7 days after.

    I googled it and it says I need a 60 grit sanding disc. But I can only hire a floor grinder that has some blocks attached. It’s this product in link. To me this may be too aggressive? Or would this be ok to use?
    Thanks
     

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  2. Kilojade

    Kilojade Member

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    Pic
     

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  3. Paul webb

    Paul webb Well-Known Member

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    It looks like it winds down to the desired height, so as long as you don't wind it down too far, you should be able to just skim it.By the time you have paid for the hire and bought the blocks, you may be aswell buying a cheap floor buffer off somewhere like eBay
     
  4. Kilojade

    Kilojade Member

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    Ar so can adjust hight that’s good! They said it’s £120 with the blocks per day will only take me a day. its 130m2 so defo need a big machine like this
     
  5. Kilojade

    Kilojade Member

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    Also how do I no how much to skim off?
     
  6. dazlight

    dazlight Super Moderator

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    What area are you in. Someone on here might know someone who can help.
     
  7. Kilojade

    Kilojade Member

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    Runcorn mate. I have been told it needs to be sanded 4-7 days after. But online it says 7-14 days ? It is a low latency thermo screed but it’s a cold empty house. And this weeks weather isn’t great. I reserved a str701 for Tuesday. But they said it’s a 50/50 it will be available just depends on the guy who has it now if he finishes if he doesn’t then it’s 1 of them diamond cut ones from speedy.
     
  8. Scf

    Scf Well-Known Member

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    Give Neil at QDP a call on Monday, there in Ellesmere Port. He's always got plenty in stock and knows what he's talking about. Numbers online.
     
  9. Kilojade

    Kilojade Member

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    It’s been 2.5 weeks and it’s still too wet to sand :( obviously just to cold for it to dry. I have asked my plumber to get the ufh going to help dry it just hope the Laitence hasn’t gone hard?
     
  10. mjfl

    mjfl Well-Known Member

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    Laitance can be ground off even after a couple of years. Best time to do it is after 28 days of installation as it will still give off laitance.
    You need to grind back to aggregate.
    Make sure you have an H class vacuum with at least two motors and more than 450mh3
     
  11. Kilojade

    Kilojade Member

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    Ok thanks mate so do you think I am passed the sanding it off stage now. Even though it’s still wet well every day I rub some sandpaper on it and it still clogs the paper.

    I thought maybe once heating is on and when I keep testing the floor with sanding paper soon as that day comes where the sandpaper doesn’t clog is the day I need to sand it?

    luckily it is a low laitence screed so maybe doesn’t need much grinding if I do have to grind it
     
  12. merit

    merit Well-Known Member

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    Just force dry it and float over it. What a palaver
     

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