Concrete floor come away from wall

Discussion in 'Buildings & Infrastructure' started by D14, Jun 14, 2018.

  1. D14

    D14 Member

    We put a new floor into an existing grain shed 3 years ago and due to shrinkage theres a gap about 3cm wide all the way around. We've tried putting cement into it but the grain bucket lifts it away once its become brittle. Any ideas of something better? Concrete isn't any option because the gap isn't big enough for it to bind together and a local concrete guy has had a look saying he'd need to cut away about 2ft for it to stand a chance and even then he wasn't keen.
    Last edited: Jun 14, 2018
  2. Steevo

    Steevo Member

    10cm? That seems a huge amount.

    I've had floors shrink about 1-2cm and just filled those with panel mastic. Works well and stays flexible in case of further shrinkage/expansion. Could work out expensive if filling 4" wide gaps though.
  3. D14

    D14 Member

    Typo now corrected. 3cm average.
    I tried the panel mastic initially but it didn't seem to stick very well and when dried was like a window wiper blade.
  4. Dry Rot

    Dry Rot Member

    Do you not need to paint the edges with cement/water mix to get a bond?
  5. D14

    D14 Member

    Tried that before last harvest and now its all opened up again.
  6. I agree with Steevo, panel mastic is a good option, depending on area size though.

    As for your grain bucket pulling the cement out, if you have a bucket where the wearing edge is wider than the bucket itself, cut it back flush with the sides. I've had this problem before with a shed that was once used as a silage pit and had wooden sleepers on one side wall, the wearing edge would get under the bottom sleeper when scraping tight to the edges and lift the whole lot up.
  7. Badshot

    Badshot Member

    I had this problem, it wasn't shrinkage though, the walls were pushing out as the walls weren't tied into the floor.
    No one could tell me how to stop it happening so I attached another barn to it and concreted it properly
    The gap was increasing every year, it's now stopped.
    Get a long straight edge and spirit level, you might be surprised by how far out of upright the stanchions are.
    HBush, onesiedale, S J H and 2 others like this.
  8. D14

    D14 Member

    We've checked them and its definitely the floor as its also coming away from a central concrete panel wall. Apparently concrete mixes with fibres in for strength shrink more than basic concrete. Its also got underfloor tunnels in it that are sending heat which hasn't helped matters.
  9. Badshot

    Badshot Member

    Keep an eye on it.
    The floor on the new barn hasn't shrunk more than 5-10mm.
    , in fact I don't think there's a gap along the concrete panels at all.
  10. Dry Rot

    Dry Rot Member

    You could always give this organisation a ring and see if they can offer advice. All it would cost is a phone call.
  11. Exfarmer

    Exfarmer Member

    Bury St Edmunds
    Dow corning C60 its amazing stuff.
    After applyication use a finger covered in a suitable glove dipped ina fairy liquid mix to smoothe off
  12. HBush

    HBush Member

    Badshot- You are not the only one to find the wall moving away from the floor. This has happened in my shed when mucking it out. A pity that I do not have room for a shed on the other side though.
    Badshot likes this.
  13. You want this
    HBush likes this.
  14. Dman2

    Dman2 Member

    Durham, UK
    we poured hot tar into a gap in one of our buildings
    Been there a lot of years now
    vinnie123 likes this.

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