Posting a message to the forum will remove the above advertisement
  1. Checkout our Tilers Insurance area for awesome prices on Van Insurance and Public Liability Insurance for Wall and Floor Tilers

  2. Underfloor Heating by uHeat

Discuss Screed & wet UFH issues. in the Underfloor Heating Forum area at TilersForums.co.uk.

  1. Sean Kelly

    Sean Kelly Trusted Advisor Professional Tiler

    Location:
    Ruislip
    I went to see a floor on Saturday. Roughly 12sqm of screed with wet UFH in a ground floor extension. The screed went down last week.


    The surface of the screed was very rough and I could scrape up parts of it into my hand (very sandy). I could see and feel spongy insulation, as some of it was actually on the surface of the floor.


    The wet UFH is actually part of the central heating. I believe the builders removed a radiator and connected the return and flow to the UFH pipes.


    Nobody knows how deep the screed is, but the heating was turned on literally a few days after the screed had been laid. There is no ‘zoning’ and I believe the heating has been turned up high.


    The heating is on a megaflow and several leaks appeared upstairs when the heating was turned on.


    My advice was to carpet/vinyl or lay a wooden floor.


    Questions:

    1. Is this form of UFH normal?
    2. Can anything be done with the screed?

    I think I might know the answers to both questions, but I thought I should put it out there. What makes matters worse is that the new extension is part of a lounge. The old part of the lounge does not have UFH. The couple want 60x60 tiles and they want the grout lines to line up with the tiles in the hall and kitchen (also 60x60)....the old tiles were laid about 5 years ago. Therefore I am not able to span a tile across a heated and unheated floor.

    Insulation showing:
    20171202_135920.jpg

    Sandy top:
    20171202_135934.jpg 20171202_135945.jpg 20171202_140027.jpg

    New screed (left), flat old screed (right)
    20171202_141728.jpg
     
  2. Localtiler

    Localtiler Professional Tiler Top Contributor

    Location:
    Yorkshire
    Sean, don’t get involved mate.
     
    • Agree Agree x 1
  3. Chalker

    Chalker Trusted Advisor Professional Tiler JOTM Winner

    Location:
    Tadcaster
    Walk away mate!
    Having no manifold, or blending valve. Will make the pipework run at the same temp as the rads. This could be up to 80 degrees!! It will ruin any floor that is laid.
     
    • Agree Agree x 3
  4. Ajax123

    Ajax123 Tilers Forums Pro - Screed Advisor Trusted Advisor Professional Tiler

    Location:
    Lincolnshire
    Don' walk away from this one..... RUNNNN!!!!
     
    • Agree Agree x 1
  5. impish

    impish Trusted Advisor Professional Tiler

    Location:
    Lancashire
    Installed by idiots?!
     
  6. Sean Kelly

    Sean Kelly Trusted Advisor Professional Tiler

    Location:
    Ruislip
    Thought you would all say that.

    The other complication is that the customer is my GP and my neighbour. I have told them straight, that it is not suitable for tiling onto but I would investigate if anything could be salvaged from the situation.
     
  7. Ajax123

    Ajax123 Tilers Forums Pro - Screed Advisor Trusted Advisor Professional Tiler

    Location:
    Lincolnshire
    Ok. I see your dilemma. In terms of the screed it is clearly badly laid and poorly mixed and compacted. It is also of indeterminate depth which means as it is it should not be tiled. the insulation is the bit that makes it most difficult as there are no thin screed systems that can be laid at the sorts of depths you would need. Dealing with poor compaction and poor mixing even with very low cement contents is doable but only if sufficient depth is available.
     
  8. antonio

    antonio Trusted Advisor Professional Tiler JOTM Winner Top Contributor

    Location:
    italy
    it is possible to execute it.
    but then, you should change your doctor and home.
    I would explain the situation to the doctor well.
    usually doctors understand.
     
    • Agree Agree x 1
    • Funny Funny x 1
  9. Ajax123

    Ajax123 Tilers Forums Pro - Screed Advisor Trusted Advisor Professional Tiler

    Location:
    Lincolnshire
    If you could excavate two or three small samples to find out how deep it is if it is sufficiently deep you could use a stabilising epoxy such as PSRS from Ardex or PHS from Flowcrete to stabilise and harden the screed. It would then be suitable for tiling. If it is not deep enough then you might as well call it a day and walk away. Im sure regardless of the fact he is your doctor and your neighbour he would rather have a proper job done. I assume he has paid for the screed in which case he can probably kiss that money goodbye...
     
  10. Rosco100

    Rosco100 Professional tiler Professional Tiler

    Location:
    Inverurie
    Run forest Run !
     
  11. LEE MAC

    LEE MAC Trusted Advisor Professional Tiler JOTM Winner Top Contributor

    Location:
    BELFAST
    The cheapest solution to this problem is to pull the screed up (2-3hours work) get a competent plumber/heating engineer involved, rescreed and tile. Job done!
     
    • Agree Agree x 1
  12. jcrtiling

    jcrtiling Professional Tiler TTA Member Top Contributor

    Location:
    Salisbury
    It'll be alright it's been done by a builder you can trust them
     
  13. Ajax123

    Ajax123 Tilers Forums Pro - Screed Advisor Trusted Advisor Professional Tiler

    Location:
    Lincolnshire
    Not necessarily Lee. it depends largely on the area to be treated. As I said it is more dependent on depth than anything else. if you take up the screed you are likely to lose the pipes and possibly the insulation as well which bumps up the price. An epoxy repair compound can often be the best and most cost effective repair to these sorts of scenarios. That said if it were in my house, not that such a rubbish screed would ever find house room in my house, I would indeed want it removed and replaced but at the builder/screeders cost. The issue with that in this instance is I suspect the screeder is long gone
     
  14. Chalker

    Chalker Trusted Advisor Professional Tiler JOTM Winner

    Location:
    Tadcaster
    Irrespective of the screed, the pipework needs controlling. Having no mixing set/manifold, will destroy anything that's laid on it.
     
  15. impish

    impish Trusted Advisor Professional Tiler

    Location:
    Lancashire
    It'll be nice and toasty though!
     
  16. Sean Kelly

    Sean Kelly Trusted Advisor Professional Tiler

    Location:
    Ruislip
    Many thanks Alan and lads, all I can do is report this discussion back to my Doctor. Shame we can't X-ray the floor!!

    I would also like to know the outcome of this issue. So will request that she keeps me in the loop.

    Cheers
    Sean
     
    • Like Like x 1
  17. Chalker

    Chalker Trusted Advisor Professional Tiler JOTM Winner

    Location:
    Tadcaster
    You can, well sort of.
    I have a FLIR camera for my phone. Very handy to trace pipework in floors.

    161117094344.jpg
     
  18. Sean Kelly

    Sean Kelly Trusted Advisor Professional Tiler

    Location:
    Ruislip
    Wow !!
    I just Googled that. Looks pretty smart.
     
  19. Ajax123

    Ajax123 Tilers Forums Pro - Screed Advisor Trusted Advisor Professional Tiler

    Location:
    Lincolnshire
    Missed that....you're completely correct. Running an underfloor heating sysem too hot is also a health risk. It has been linked in some studies to thrombosis. Maximum surface temperature should be 27C with an anticipated surfacd temperature around 22 to 23C. This would require a flow temperature of around 40 to 45 in sand cement. Radiators tend to run at 60+. Running radiator temperature flows will yeild a temperature closer to 45 to 50C in sand cement. This can be dealt with in small areas using a Return temperature limit valve but these are not suitable for anything over about 15m2
     
  20. John Benton

    John Benton Trusted Advisor Professional Tiler JOTM Winner

    Location:
    Leeds
    The top of the screed does looks very sandy, no way should you be able leave finger marks when scraping the surface. I wouldn't really be happy putting any type of floor covering over that screed combined with the heating system.

    I'm also intrigued to know, when he called for an appointment, did you tell him there were no free times until 2 weeks on Thursday, and he would have to ring first thing in the morning?
     
    • Funny Funny x 1
Loading...
Similar Threads - Screed issues Forum Date
Tiling floors on substandard screeds.... The Welcome Forum Nov 23, 2017
Porcelain Priming screeded floor Tiling Forum Nov 20, 2017
Find a Tiler Post a Job Ask a Question Tile Events Tile Pics Blog Adhesive Poll Handy Downloads