Easy questions about laminate underlay?

Discussion in 'Builders' Talk' started by SteveMJ, Jul 30, 2013.

  1. SteveMJ

    SteveMJ Active Member

    Hello,

    I'm about to fit my first laminate flooring in a kitchen and have a few (simple) questions:

    The existing floor is boards plus a section of concrete that was laid about 12 months ago. The boards and concrete are level. 

    I am testing for any moisture through the concrete by placing a large piece of plastic over the concrete  - I plan to leave this down for 24hours and see if any dampness accumulated underneath. Is this a reasonable method to check?

    Can I use an underlay that includes a DPM over the wooden boards and over the concrete, i.e. same underlay over the whole floor?

    How do I determine if I should use 2, 3 or 5 mm thick underlay?

    I am not flooring under the kitchen units and expect to stop the flooring ~ 10 mm from the base unit's legs. Is there any risk that the laminate may come apart?

    Thanks for your help,

    Steve



     
  2. Sean_ork

    Sean_ork Screwfix Select

    why not just assume there will be damp and lay a sheet of 1200 gauge plastic over the conc - you'll save yourself 24 hours by doing that

    the thickness of the underlay is dictated either by the manufacturer, or your personal preference - or, perhaps more importantly, the need to match the levels of any existing floor finishes
     
  3. SteveMJ

    SteveMJ Active Member

    Well, over 48 hous later there is no damp indicated - do I still need the DPM?   I have to wait for the flooring to acclimatise anyway (as well as some other jobs to do as well.

    I don't have a personal preference for underlay thickness as I am unaware of the effect.  That's why I was seeking others experiences.  As far as I am aware the floor is good and flat.

    Thanks,  Steve
     
  4. goldenboy

    goldenboy Super Member

    Alright Steve, really no need to bother with a separate DPM under a laminate. Just use Quickstep Combilay. It has a built in DPM and is very reasonably priced. I have laid many many laminates and engineered floors over it with zero problems. As for thickness i think the Quickstep is 3mm and that is perfectly adequate.

    Laying a separate DPM under and underlay is a waste of time and effort. Never heard of it being done since all in one underlays were introduced.
     
  5. Sean_ork

    Sean_ork Screwfix Select

    most underlay's aren't properly moisture proof .....

    that's why dedicated DPCs such as Quick-Step Screen are available - ridiculous price for what it is, far better to lay single contiguous sheet of proper EDPM
     
  6. goldenboy

    goldenboy Super Member

    Really confused here Sean, do you mean rubber EPDM as in your last post or using a 1200 plastic DPM as in your first post?

    Instead of saying most underlays arent properly moisture-proof and then advocating using a separate EPDM or DPM and underlay, why not use the correct product which would be Quickstep Combilay which is a combined dpm and underlay and costs perhaps £1.20sqm? That is what everybody uses and infact if a Quickstep floor is going over it is required for the warranty.

    Explain why it is far better to not use a specifically designed product designed to provide a dpm,sound resistance and underlay and instead use a separate DPM or EPDM and underlay.

    All seems very longwinded,confusing,timeconsuming and expensive. Might be a novel approach but why not buy and use the correctly designed product.
     
  7. Sean_ork

    Sean_ork Screwfix Select

  8. goldenboy

    goldenboy Super Member

    Because Quickstep Combilay is pretty much an industry standard, in fact most engineered manufacturers accept it as warranty meeting, unfortunately you would need to lay a few floors for customer to realise that.

    Think you are a little confused about your DPMs and EDPMs, genuinely interested as to what EDPM stands for. You linked to a DPM, nearest to EDPM is  EPDM which is a rubberised sheet, different stuff.

    As for the "bear in mind this is expensive" stuff, not sure what that refers to. The OP wants a suitable underlay for over concrete and timber with a moisture barrier, Quickstep Combilay does that for around £1.20 sqm so £15 for an average room.The DPM you recommend is £40 alone before you get your underlay.

    I would be halfway through laying the laminate following manufacturers recommendation before you finished your heath robinson DPM underlay combination.

    Proper product, proper quick, proper job.
     
  9. goldenboy

    goldenboy Super Member

    Steve,

              Ignore all the nonsense below. Quickstep Combilay will be ideal for your requirements over concrete and timber. As long as the joints are clicked all the way home separation shouldnt be a problem. Your plans for under the cabinets is fine.

                       Good luck with your project.
     
  10. Sean_ork

    Sean_ork Screwfix Select

    hmmm ..... combilay is industry standard eh - righto

    I think you better do a little research on EDPM chappy - that DPC i've linked to certainly isnt rubberised - and takes a couple of minutes to cut and lay out

    and I dont know if you've noticed but thats an entire house worth of DPC for £40 - same item in any builders yard will be about £20 (hence my ''expensive stuff'' comment')

    I'll leave you in peace to carry on spamming your favourate flooring



     
  11. goldenboy

    goldenboy Super Member

    Thats my point you have linked to a DPM which is a plastic one but equally have referred to an EDPM which doesnt exist. Nearest acronym to your mythical EDPM is EPDM which is a rubberised product and very different to a £40 DPM

    You are clearly very confused and it would be a fair conclusion to draw that you actually arent anywhere near as knowledgeable as you claim.

    One of us has done hundreds of floors in the exact same scenario as the OPs without problem and I am pretty sure its not you.

    I know whos advice I would rely upon.

    Oh and I get my flooring and underlay direct from the importers and manufacturers rather than a "builders yard". Pretty sure their product knowledge is better as it is their core business.

    No spam, OP wants advice as to the best product and thats it.

    Again what does EDPM stand for?
     
  12. Sean_ork

    Sean_ork Screwfix Select

    I'm not going to spoon feed you, nor am I going to feed your apparent need to squabble, but perhaps the OP wants a DIY project and doesn't want to waste money employing the likes of you - perhaps he wants to buy from a builders yard or a local shed

    Ethylene .........  am sure you can figure the rest out
     
  13. goldenboy

    goldenboy Super Member

    Pretty straightforward here Sean, OP wants advice on underlay, you have given him rum advice and seem very confused about what products you recommend.

    One could draw from that that your advice is theoretical advice based on just googling, wheras mine is based on years of actual work. It does seem that your googling should improve a little.

    Pretty sure that your reference to Quickstep Screen came from googling Quickstep DPM rather than Quickstep Combilay, I guess the moral for you would be steer clear of areas that you arent too up on.

    <h2></h2>
     
  14. goldenboy

    goldenboy Super Member

    Why then would he want to waste money and time following your duff advice rather than simply purchase the correct product and use it correctly.

    Remind me again how much actual work you have done

    Seems to be a regular theme on here, Sean jumps in and decides black is white and then makes a plonker of himself insisting he is correct when it is clear he is wrong

    Can I suggest your next google should be "how to stop digging when in a big hole
     
  15. Sean_ork

    Sean_ork Screwfix Select

    I linked directly to the product I'd recommend for solving any actual or potential damp problems - there's nothing rum or confusing about that

    I think the real moral is don't keep shoving a product down someone's throat ......
     
  16. joinerjohn1

    joinerjohn1 Screwfix Select

    Goldenboy is quite correct, Sean. Use the correct product, instead of cobbling together some "HeathRobinson" affair which would void any warranty on the product.
     
  17. SteveMJ

    SteveMJ Active Member

    Well, my question has created quite a lot of discussion.

    I'm proposing to use something like this:  Its available in 3 mm and 5 mm thick.  If 3 mm thick is OK, then is 5 mm better (more cushioning, more insulation)?

    [​IMG]

    It is also low cost IMO ~£1 per sq m.

    Thanks, Steve
     
  18. Sean_ork

    Sean_ork Screwfix Select

    if that isnt a Quickstep product it's no good, apparently
     
  19. joinerjohn1

    joinerjohn1 Screwfix Select

    Looks better than a piece of blue plastic underneath.
     
  20. Sean_ork

    Sean_ork Screwfix Select

    am sure that product will do the job

    if it's an unheated slab, and if you have the height, perhaps consider laying a thin (25mm) layer of XPS rigid insulation down first. this will provide considerably more insulation than any underlay, it will also give excellent sound deadening results - even the best dedicated underlays can't match the thermal performance of XPS or other rigid insulation

    SF sell a few options, such as the one linked below, which has the DPC I previously linked to, bonded - however you then don't have a contiguous DPC so it would need lapping and joining

    http://www.screwfix.com/p/acoustalay-foam-underlay-with-dpm-3mm/45461

    the thickness of whatever you lay is dependant on any requirement to match any existing levels, at door openings and changes in floor covering types
     

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