1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Allowing an old wall to breathe without using lime plaster

Discussion in 'Plastering and Rendering' started by Reejoc, 4 Sep 2020.

  1. Reejoc

    Reejoc

    Joined:
    29 Nov 2012
    Messages:
    24
    Thanks Received:
    0
    Location:
    Worcestershire
    Country:
    United Kingdom
    If you've got an old house, or if you simply want to avoid damp walls then the mantra is Breathability. Which translates as lime plaster on the internal side of exterior walls.

    BUT - it's hard to get hold off, eye wateringly expensive, difficult to use, and if you can't DIY it then suitable plasterers are few and far between.
    In other words for the average Joe/Jo it's just not an option.

    Now one of me mates said - don't worry about all that, just baton out the wall, use normal gypsum plasterboard/skim and leave a inch or so gap at the bottom which is then covered by the skirting

    This sort of makes sense, in that air would presumably circulate over 99% of the masonry not covered by baton. You could even dot and dab with a similar gap. Moisture that has condensated isn't trapped as long as there is a gap under the skirting - easy when installed over timber floorboards in an old house..

    What do you think? Is this a legitimate and cheap way to control damp in an old wall or does the science not add up?
     
  2. Sponsored Links
  3. StephenStephen

    StephenStephen

    Joined:
    1 Apr 2008
    Messages:
    552
    Thanks Received:
    55
    Location:
    Devon
    Country:
    United Kingdom
    I found the book "The Damp House" really useful to help get my head around this kind of question. https://www.crowood.com/details.asp...Guide-to-the-Causes-and-Treatment-of-Dampness

    I'm not sure I'd agree with everything you say about lime plaster - it certainly can be difficult to get hold of for me - but then I quite like a trip out in the countryside to Mike Wye.
    Eye wateringly expensive? Yes, in my experience if you pay someone to do it, but not if you diy.
    Difficult to use - not in my experience as a diy plasterer - it's lovely to work with, and you've more time to work it.

    I was thinking the other day how it's ideally suited to diy - it's a slower process, and can want a bit of tending whilst it goes off to manage the moisture level, so if it's in your own home - a quick spray now and then is no problem. For a professional though, being a slower process, then having to travel to revisit and check, and then return for later coats - that is going to be less convenient.

    I find Jane Schofield's booklet on lime invaluable if I forget what to do: https://theblackdogpress.bigcartel.com/product/lime-in-building-a-practical-guide-by-jane-schofield, as well as Mike Wye's videos: https://www.mikewye.co.uk/product/dvd-using-lime-in-renovation/ (I especially like the dodgy music)

    Other people on here who know what they're talking about, will be able to direct you to previous useful threads on drylining
     
    • Thanks Thanks x 2
  4. jacko555

    jacko555

    Joined:
    5 Feb 2005
    Messages:
    170
    Thanks Received:
    18
    Country:
    United Kingdom
    Not an expert.

    Wont this cause a cooler void that risks condensation? Warm air in, cool air out, dew point hit and damp where you cant see it?

    I thought the methods to do this involve a vapour barrier, and, ventilation on the cool side.

    Interested to hear what more knowledgeable people think
     
  5. ted456

    ted456

    Joined:
    11 Mar 2020
    Messages:
    179
    Thanks Received:
    46
    Location:
    shrewsbury
    Country:
    United Kingdom
    OP,

    A lime render mix of 3:1 or 4:1 sand & lime is the most simple, inexpensive and effective method for interior or exterior rendering.
    The "Lime Plaster" that you refer to is not necessary, & can be dangerous to the inexperienced user.

    The books on Remedial work that i've noticed seem to have been written by people with no actual experience of site work on the tools - they've contained many mistakes and lots of practical ignorance of site work.
    They are often recommended by people with even less experience than the writers.

    Still the best short booklet on the subject is:
    "Guide to Identification of Dampness in Buildings" by Graham Coleman.
    Problem is that much of the book is pretty technical for DIY'ers or householders.
     
  6. bennymultifinish

    bennymultifinish

    Joined:
    21 Apr 2020
    Messages:
    1,917
    Thanks Received:
    291
    Country:
    United Kingdom
    it’s perfectly fine, dot and dab on stone is a no no for me though. and i’d use vapour boards not standard pb.
     
  7. ted456

    ted456

    Joined:
    11 Mar 2020
    Messages:
    179
    Thanks Received:
    46
    Location:
    shrewsbury
    Country:
    United Kingdom
    OP,
    To repeat what skilled, experienced people know: its far from fine in terms of safety and ease of use for a DIY'er.
    Plus its expensive. Stay away from it and as above, if you want to render then use a Lime render - safe and cheap.

    FWIW: Dot&Dab adhesive will transmit moisture to the decorated surface - it often shows a distinctive regular pattern that can be seen in lots of previous pics on here. D&D dont go with damp.
     
  8. StephenStephen

    StephenStephen

    Joined:
    1 Apr 2008
    Messages:
    552
    Thanks Received:
    55
    Location:
    Devon
    Country:
    United Kingdom
    This makes no sense to me - I'd advise the OP to ignore this histrionic outburst from ted456

    Describing lime plaster (meaning lime putty and sand, I presume) as 'far from fine in terms of ease of use and safety' is flatly contradicted by my experience as a DIY'er with no other experience of plastering,

    and then ted456 goes on to describe lime render (hydraulic lime and sand) as safe and cheap, which is pretty much the same to use as lime plaster, but with the need to use a mask whilst mixing the powder.

    I wonder ted456 is confusing lime plaster with quicklime?

    Though, to be honest, you would probably still would find it easier to dry line!
     
    • Like Like x 2
    • Thanks Thanks x 1
  9. Sponsored Links
Loading...

Share This Page