Audi-Evo & Others - help appreciated

Discussion in 'Carpenters' Talk' started by dangerousdistress, Sep 19, 2008.

  1. dangerousdistress

    dangerousdistress New Member

    Audi,

    Your help would be appreciated in determining the cause of a defective timber floor installation.

    Background - 1960s House with solid floors over laid with thermo plastic tiles, subsequently removed. Fitter has installed solid oak planking, glued to underlying screed with Ball B92 Adhesive. Floor subsequently cupping upwards / failed and adhesive not bonded to slab / latex. Fitter believes due to failure of DPC. No expansion gaps at perimeter.

    MI states may be glued with elastic polyurethane on "dry" concrete, but during installation instructions states that a vapour barier should be provided to control moisture from below.

    Have checked slab with Protimeter which read between 3 & 15% WME which whilst not ideal, is not excessive for house of this age.

    My view is that the floor was incorrectly spec'd / laid and should have been spec'd as floating with vapour barrier beneath. It might also have been preferable to use engineered timber

    Thanks for any advice

    DD
     
  2. !!

    !! Active Member

    I'm not familiar with that adhesive but usually a primer/ liquid dpm is applied first (bona 410 is my usually one mainly because I like saying bona).

    Lack of expansion, is that there appears to be no expansion gap now or did the fitter never leave one.

    how long was the flooring acclimatised, what conditions were like i.e recently plastered?.

    What size boards are we talking.

    Also is the flooring cupping upwards due to it shrinking or is it buckling (pressure pushing it upwards like techtonic plates forming volcanoes)
     
  3. dangerousdistress

    dangerousdistress New Member

    Thanks for the reply gonzo

    I wasn't aware that Bona was also a liquid dpm. Anyway that beside the point.

    from way I can ascertain there never was any form of expansion gap. Flooring in the room for 2 / 3 weeks, but not unpacked nor stacked on batterns. The room is a normal sitting room. No recent wet trades / redecoration or other moisture inducing activities.

    Board size prob 100mm width. room 4000 wide.

    Floor buckled upwards rising to dome in center
     
  4. !!

    !! Active Member

    yeap moisture induced expansion, possibly concrete, humidity or lack of expansion gap.

    Did you see a lack of expansion gap within 24hrs of fitting, I only ask because if the flooring has soaked up a lot of moisture it will have filled it first then started buckling
     
  5. Had a quick look at the Ball info, it implies that B92 should be laid on to a clean floor

    "Concrete and sand/cement screeds must be fully cured and any laitance or surface treatments must be removed"

    That to me means that the old adhesive should have been removed before using this adhesive or isolated from the adhesive by the application of a suitable primer/leveling compound.

    Can you describe the state of the back of the flooring, ie is the adhesive stuck to the board or is stuck to the sub-floor.

    If the latter then the boards were dusty when laid, if the former then the adhesive has let go of teh subfloor, and therefore not compatable with the adhesive left from the plastic tiles.

    With regard to the cupping, is this the whole floor or is it individual boards?

    If it's individual boards with adhesive stuck to the back of them then it looks like the moisture content of the sub-floor is too high.

    It's difficult to compare the moisture info you gave with the info on Ball's site as they (Ball's) refer to relative humidity which as far as I know relates to air bourne moisture rather than the moisture content of the object.

    How big an area is the room?

    Sorry lots of questions but it's always difficult answering this sort of query from a short description.
     
  6. dangerousdistress

    dangerousdistress New Member

    XKF thanks for the reply.

    The leveling compound was laid over the remains of the tile adhesive / synthaproof. However the leveling compound has almost a mirror like smooth surface. The adhesive has bonded to the back of the timber boards and has come away fom the subfloor including the levelling compound which remains fully adhered (where checked)

    The room is apprx 4m wide x 6 m long and the buckling was across the whole floor width. I have got some photos, but not sure how to upload.

    DD
     
  7. audi-evo

    audi-evo Active Member

    the floor is cupping, or is it buckling?
    How long has it been down?
     
  8. dangerousdistress

    dangerousdistress New Member

    Hi Audi,

    My understanding is that cupping means the outer edged of the floor / boards lift to form a cup. If so then the floor buckled - ie lifted in the center some 100 mm (like an upturned boat)

    DD
     
  9. audi-evo

    audi-evo Active Member

    how long has it been down?
     
  10. dangerousdistress

    dangerousdistress New Member

    sorry audi. missed the vital question. Buckled within 7 - 10 days of completion
     
  11. !!

    !! Active Member

    thats bridging then but if I went really technical I'd say it's totally f*cked.

    Does sound like the subfloor wasn't correctly primed so low adhesion which with the lack of expansion and no damp proof really didn't help. Fitter is at fault
     
  12. !!

    !! Active Member

    Whats the rooms relative humidty been like, I assume this is your floor we are on about
     
  13. dangerousdistress

    dangerousdistress New Member

    yep my floor. No sig change in humidity or use before or after.
     
  14. audi-evo

    audi-evo Active Member

    ok, then if it was fitted with expansion and was acclimatised it has taken in moisture.
    Why?
    Is it because of the failure or non existance of a dpm on the subfloor or something else.
    Although it is possible the moisture is from the subfloor it is not the only possibilty.
    It is more likely to be humidity.
    If the humidity in the room is above 60% then the floor will take in this moisture and expand, as it expands it will close the expansion gaps hit the perimmiter walls.
    Then as it expands more it has no where left to go so will sepperate from the subfloor and rise up, buckling.
    If the floor is lifted and a dpm installed then the floor is relaid and humidity is the problem it will just happen again.
    You need to be sure you can constantly control the environment the wood is "living" in, you need to maintain a constant temperature of around 18-24deg and 40-60% humidity.
    Outside of these windows will cause the floor to fail again.
    With due respect it is easy to lay the blame at the fitters feet but the customer must understand how vital it is to maintain these conditions.
    Most people have the floor fitted and do nothing to maintain this crucial environment.
    When the floor fails, the fitter gets the blame.
     
  15. !!

    !! Active Member

    so it's never been above 70% or below 40% and theres been no clothes on the rads
     
  16. audi-evo

    audi-evo Active Member

    no sig change, mmm, ok,
    I will use outside humidity as an example to illustrate,
    bbc, weather for my postcode,
    sat 64%
    sun 63%
    mon 63%
    all borderline but ok i would say.
    however
    tues 75%
    oh dear
    wed 80%
    now in the poo!
    If outside humidity can change that much why would you think it would be any different inside?
     
  17. !!

    !! Active Member

    very fair audi, above 60% for 5 days add in the human factor of cooking etc. If the fitter isn't to blame I hope he took enough photos like I did ;)

    Still doesn't sound like the flooring was stuck to the sub floor that well though

    Have you got a dehumidifer?
     
  18. dangerousdistress

    dangerousdistress New Member

    Thanks for the advice guys. Theres never been clothes on the rads or owt like that.

    Whilst I appreciate that there is a humidity / temp band beyond which there may be problems, I suspect that the fitting was incorrect either becuase the subfloor was badly prepared or because the floor should have been otherwise spec'd ie floating or engineered timber with DPM /other vapor barrier between the boards and subfloor,

    1 question I would like to ask is -- Is cupping caused by moisture from below & buckling / bridging by moisture from above or are the defects not that specific.

    DD
     
  19. audi-evo

    audi-evo Active Member

    exactly gonzo, a dehumidifier is crucial.
    I would get a cheapo hygrometer and take a reading everyday for a fortnight and see what is happening.
    If the humidity is to high put a dehumidifier in and see how many buckets of water you get out of it.
    Poor adhesion or not, what caused the floor to expand, bearing in mind it was acclimatised.
    If it closed a 12mm gap in a week it must have sucked a lot of water up and that much would rip nails out of the floor never mind glue.
     
  20. !!

    !! Active Member

    cupping is usually seen in timber that has dried as opposed to expanded.

    Bridging is when the flooring forms a bridge i.e boards lifted off the sub floor

    buckling is when the nailed end has remained fixed but the groove end has lifted.

    What is the cross grain run, I'll do a coeffiecnt for dimensonal change in oak calculation for you (plain sawn & quarter) if the amount of expansion is beyond a reasonable amount you may have to just suffer it
     

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