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Damp concrete floor preparation for parquet

Discussion in 'Subfloor Preparation' started by cosmicbeard, Dec 18, 2013.

  1. cosmicbeard

    cosmicbeard Member

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    Greetings all,

    I have moved into a house built roughly in 1900, there is a parquet floor in the living room which has suffered from damp recently from the concrete floor - I had a damp inspection carried out by an independent surveyor which confirmed this. I have lifted the parquet blocks. As expected there is patchy bitumen adhesive residue all over the floor (not intended for dpm, or if it was it has failed and now needs rectifying). The floor is quite level other than the 1mm difference where the bitumen is. Hopefully there is an image attached below.

    I have read through all (I think) the parquet/damp concrete sub-floor threads in this forum and picked up some great information. I have spoken to F.Ball, Sika and Ardex about how best to form a new DPM - so far my best option is this.

    1. Clean floor (but leave bitumen residue that is sound).
    2. Level with Arditex NA (advised by Ardex to isolate bitumen before DPM)
    3. Epoxy DPM.
    4. Level with Arditex NA again (advised by Ardex to form sandwich DPM)

    This will work out quite expensive (for me anyway - £500 ish for floor leveller, dpm and parquet adhesive). Does anybody have any other suggestions/advice/cheaper methods of how to damp proof the floor effectively so that I can relay the blocks? Perhaps visqueen, plywood, then parquet? I would not want to raise the floor level too much.

    Many thanks in advance. (I have also posted this thread on diynot.com)

    2013-12-17 20.35.19.jpg
     
    cosmicbeard, Dec 18, 2013
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  2. mjfl

    mjfl Well-Known Member

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    Hi and welcome,
    Need not say anymore other than the other option you have would be to go with one of the other manufacturers you have mentioned, IF they work out cheaper for you.
    Whereabouts are you based and perhaps someone on here could visit??
    Look in find a fitter at the top of the page.
     
    mjfl, Dec 18, 2013
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  3. cosmicbeard

    cosmicbeard Member

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    Many thanks for the reply. I have had a local fitter out to look at it - the quote was pretty reasonable but I can't afford it with my budget.

    The reason I have chosen Arditex NA is because they are the only manufacturer that says their product is compatible with the bitumen residue. I haven't checked to see if the others are cheaper as they advised all the bitumen adhesive needs to be mechanically removed.

    Can you (or anybody else) offer any advice/info/opinions regarding Sika/F.Ball/other products on top of bitumen adhesive residue?

    Cheers
     
    cosmicbeard, Dec 18, 2013
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  4. mjfl

    mjfl Well-Known Member

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    What was the installer's view on the subfloor, do you know what he was using?
     
    mjfl, Dec 18, 2013
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  5. mjfl

    mjfl Well-Known Member

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    How many square meters?
     
    mjfl, Dec 18, 2013
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  6. cosmicbeard

    cosmicbeard Member

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    Without too much investigation (i.e. hygrometers etc. - the damp was evident on the blocks however) he said he would use Sika Rapid DPM and Sika latex self levelling compound - I can't remember in which order. There was no mention about making a sandwich DPM - Ardex advised me to do another layer of levelling compound (to form sandwich DPM) but did say that some people do save money by not putting another layer on top of the epoxy DPM.

    Approximately 15 square meters.
     
    Last edited: Dec 18, 2013
    cosmicbeard, Dec 18, 2013
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  7. Trimmer

    Trimmer Well-Known Member

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    What flooring do you plan to install?
     
    Trimmer, Dec 18, 2013
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  8. mjfl

    mjfl Well-Known Member

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    Just gathering info so please bare with me.
    Can I ask your budget?
    Also what works needed to be carried out (your budget being screed, dpm and supply adhesive only) and you are going to install the blocks?
     
    mjfl, Dec 18, 2013
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  9. mjfl

    mjfl Well-Known Member

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    relay blocks I believe trimmer
     
    mjfl, Dec 18, 2013
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  10. cosmicbeard

    cosmicbeard Member

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    Hi,

    I will be putting parquet blocks back down which I have already taken up - after cleaning them all up. (they were in herringbone pattern).

    I intend to lay the blocks back down myself after installing a DPM and ensuring the floor is level.

    The budget is as little as possible (as always) - I can stretch to £500 to prepare the sub-floor but would really like to save money if possible but still achieve a good base for the parquet.
     
    cosmicbeard, Dec 18, 2013
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  11. merit

    merit Well-Known Member

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    You can't lay those blocks on ardex na!
     
    merit, Dec 18, 2013
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  12. cosmicbeard

    cosmicbeard Member

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    Will I need to use an acrylic leveling compound?
     
    cosmicbeard, Dec 18, 2013
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  13. mjfl

    mjfl Well-Known Member

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    Did you mention to the manufacturers what you were putting on the floor?
    Did they ask?
     
    mjfl, Dec 18, 2013
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  14. cosmicbeard

    cosmicbeard Member

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    Yep. Ardex said it was okay if i put down Arditex NA, then DPM, then Arditex NA again, then parquet adhesive and blocks.

    I have read on diynot.com that latex and water based compounds aren't advised for parquet blocks.
     
    Last edited: Dec 18, 2013
    cosmicbeard, Dec 18, 2013
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  15. Matt

    Matt Well-Known Member Staff Member

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    Water based is fine, actually the best product for wood flooring normally speaking. Latex is not unless over 25nm of strength. However its wood blocks so a lot less stress compared to a solid plank floor. Technically you dont need a compound with massive strength for wood blocks but its still not advised.

    What i would be thinking about is you are looking to go over bitumen adhesive with a smoothing compound and everyone is telling you that you need to remove first? i wonder why they are telling you that ?

    The bitumen adhesive has started to break down and fail ? YES?

    So if we leave the bitumen adhesive that has not failed YET how long until this starts to fail? Will it be 1 month? 1 year ?

    Have a think about it. If you go over the Bitumen adhesive and that adhesive starts to fail in say 6 months time (i might be sound at moment) and it all comes back up, what has failed? the smoothing compound of the bitumen adhesive?

    Also for the record, applying a surface dpm over a damp concrete floor is not recommended. Ardex say you can use their product tho. But what i can tell you is a epoxy dpm can not fail if mixed correctly. What can fail is the concrete/ adhesive etc its going over. If what its going over fails then you have no guaranty of any type.

    O and is was also me that wrote the 'sticky' threads on DIY NOT many years ago. They are very out dates now and most manufactures changes there methods of what was stated in the sticky threads a few years ago.
     
    Last edited: Dec 18, 2013
    Matt, Dec 18, 2013
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  16. cosmicbeard

    cosmicbeard Member

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    You make a good argument. I've been avoiding removing the bitumen for the obvious reasons of cost and hard-work. What would be the method if I removed the bitumen adhesive and make the floor sound - epoxy dpm then adhesive?

    What are the best tools for removing bitumen? Can I get it shot blasted - If so any idea of cost? Can't find much info through Google.
     
    cosmicbeard, Dec 18, 2013
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  17. Matt

    Matt Well-Known Member Staff Member

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    You can remove bitumen through shot blast / grinding. Not mush at all about it on internet. you might find a commercial painters is your best friend here as they use shot blasting etc to clean beams, old paint etc. Try your local decorators for this service.

    As for cost? last time i had someone in for me they was charging around £8 sqm to remove.

    However, if you read Ardex tech info it will say the subfloor needs to be free of oil contaminates. Bitumen is a oil contaminate so to teh book you should grind a couple of mm of the concrete. Cost for this will be a bit more than a shot blast.

    But dont forget you will still be applying a surface dpm to a subfloor with no working DPM. Really it should be dug up and replaced to Building Regs.
     
    Matt, Dec 18, 2013
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  18. cosmicbeard

    cosmicbeard Member

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    That's what the damp surveyor recommended but we can't afford that. What is the likelihood of an epoxy DPM (such as Sika Rapid DPM/Ardex DPM 1C) failing if I remove all of the bitumen, clean as much as possible (white spirit?), put leveling compound down (acrylic/water?), then epoxy DPM before sticking the wood down - considering the floor is currently damp? Something worth gambling on or simply a no-no?
     
    cosmicbeard, Dec 18, 2013
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  19. Matt

    Matt Well-Known Member Staff Member

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    Personally i would do it correctly. I run Europes largest training centre , i also do technical support for a range of manufacturers (when there is issues) and to add to that i also get sent numerous reports of failed floors. My father is out every day doing reports for court cases etc which i also get to see on a daily basis. I see on average 100 failed flooring reports a month so i can ensure you that there are a huge amount of floors that go wrong.

    We have a lot of flooring installers that do things 'wrong' as such and get away with it. I myself (in my younger less educated years) have over the years done things wrong and got away with it but everyone eventually gets bitten.

    Due to what i see on a daily basis my view is do it correct or dont bother doing it at all.

    I say the above but we can 'bend' the rules. Technically your concrete floor needs to be dug up and replaced. But if you want to take a gamble (like going a casino and betting on red or black) you are will be left with a 50/50 chance. We can however change the 50/50 odds by looking around your property and getting a idea of if the surface dpm is destining to fail or not.

    Odds against you for it to fail are -


    • Contaminates on the subfloor (old adhesive etc)

    • Weak concrete
    • USING a DPM that is not 2 part (epoxy)
    • The subfloor being below ground level of high water table of area (property at a bottom of a hill)
    • Installing a flooring that creates high stress like wood flooring (parquete / herringbone is much lower stress compared to plank)

    If you can eliminate the above then the odds are in your favor and your floor might last for many years. But please be aware that you have no guaranty.


    Also you really want to be applying a surface dpm first. THEN a smoothing compound of your choice. DO NOT use a water based compound under a surface dpm. Also note that if you prepare the concrete first then there is no need to apply a smoothing compound first. It should be DPM first then smoothing compound.

    If you work in Europe its standard practice to prepare teh concrete by shot blasting or grinding. Its the U.k that we create sandwich systems due to us trying to hide teh problem with a smoothing compound.

    Think of decorating. A good decorator will sand and prepare the surface and then apply the paint. They dont do 'sandwiches' by applying a thick layer of paint / filler etc over something to hide whats underneath and then mess around trying to get a good finish.
     
    Last edited: Dec 18, 2013
    Matt, Dec 18, 2013
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  20. cosmicbeard

    cosmicbeard Member

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    Thanks for the great advice Matt. I agree that the right way to do it is to dig up and replace but not something we can consider unfortunately. The paint is a good metaphor, especially as I've spent weeks stripping all the wood back to bare wood!

    Based on what you've said I've not got an option but to go for removing bitumen, epoxy dpm, smoothing compound. What products would you recommend?
     
    cosmicbeard, Dec 18, 2013
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