Is using NA too safe?

Discussion in 'Subfloor Preparation' started by Banks, Jan 28, 2018.

  1. Banks

    Banks Member

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    Hello Chaps,

    I use Ardex NA on practically everything! old latex with old glue, bitumen, ply, ceramics, whatever.

    Is there products which you can trust to do jobs like
    these but cheaper and reliable? I have used others in the past and sometimes it can sound hollow or cracks!

    I prime even on NA, think it flows better and have longer working time.

    Good to hear what others suggest, Cheers.
     
  2. Rugmunching

    Rugmunching Well-Known Member

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    I use CL when allowed and NA when it's needed - both depending on the subfloor but also use 300hd when possible, love that stuff and seems to flow best for me out all screeds.

    I always prime with NA also but not when I'm using a dpm sandwich system. There's plenty out there for you to use and NA isn't the cheapest so I won't use it when I don't have to. I'll mainly use CL/300hd and recently started using renovation for my ply fits.
     
  3. Spacey

    Spacey Super Moderator Staff Member

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    I only use NA if there’s no other option
    Never known it to fail but the flow isn’t great even primed
    If you’ve had hallows or cracks you’ve used something with a compression strength that’s to high for the subfloor or what ever you’ve gone over
    NA is a very low compression strength so very little pull on the subfloor as it dries and stick like s*** to a blanket
    That’s why it works

    Water based are very high Compression and yield strength so as they dry you get a lot of pull so if its over something soft it will crack to hell so only realky suitable on solid clean slabs with no contamination

    I tend to use a lot of Ardex CL the C.S. Isn’t to high and it flows really well
     
  4. Banks

    Banks Member

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    what about over old screed and adhesives, i was told by ardex rep its only meant for fresh screeds or grounded back! (f**k that!)
     
  5. Spacey

    Spacey Super Moderator Staff Member

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    You shouldn’t go over adhesives with anything only residue Most are water soluble
    I grind everything off unless an existing screed is bonded and solid but I test the compression strength first so I know what I can use over it
     
  6. merit

    merit Well-Known Member

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    If the subfloor is dry and you want low stress and good flow look at some of the gypsum levelling compounds. We use them over bitumen and old adhesive all the time.


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  7. Spacey

    Spacey Super Moderator Staff Member

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    Unfortunately adhesives don’t like sticking to gypsum based compounds They barely hang on especially PS
     
  8. lvtfooringbristol.co.uk

    lvtfooringbristol.co.uk Active Member

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    Na is a no brainier on bitumen or asphalt. Otherwise it's a Bit of spit and prime . Then whatever 2 part is on offer . never had a problem yet .. touch ply !

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  9. Banks

    Banks Member

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    You sound like the man with all the gear! fair play ;) I would love to grind everything off but no one ever speaks about grinding and just dish out NA instead or level it bond if your unlucky!
     
  10. merit

    merit Well-Known Member

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    Personally not a fan of grinding floors as most old adhesives have asbestos in and concrete has silica in which is cancerous. Get some decent extractors and masks of your doing it on the regular


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  11. Spacey

    Spacey Super Moderator Staff Member

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    Definitely don’t grind bitumen for those reasons
    Those are the situations when it’s NA or Tilemaster Super 30
     
  12. Spacey

    Spacey Super Moderator Staff Member

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    All the gear No idea :rolleyes:
     
  13. mjfl

    mjfl Well-Known Member

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    I should be dead by know then.. lol
     
  14. Spacey

    Spacey Super Moderator Staff Member

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    You grind floors that don’t need it just for the fun if it
     
  15. merit

    merit Well-Known Member

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    You got at least another 10 years in you mate


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  16. mjfl

    mjfl Well-Known Member

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    NO, I do it for the tea and cake
     
  17. mjfl

    mjfl Well-Known Member

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    oi.. and the rest
     
  18. Spacey

    Spacey Super Moderator Staff Member

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    Tea and cake to ?
     
  19. Dan2223245

    Dan2223245 Active Member

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    How do you test the compression strength?
     
  20. Spacey

    Spacey Super Moderator Staff Member

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    With a rebound hammer
     

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