Weatherstruck/ weather struck pointing with lime mortar

Discussion in 'Builders' Talk' started by Rob Denness, May 22, 2020.

  1. Rob Denness

    Rob Denness New Member

    I am looking to repoint a victorian garden wall which is about 26m2, but I need some advice on which type of lime mortar to use as I don't have extensive experience with this. My questions are:-

    1.The customer likes the idea of a weatherstruck joint, but can this be possible with lime mortar and is it acceptable?

    2. I appreciate the traditional way is a flush joint with a good tamp from a churn brush, but if I go down the weatherstruck route what type of mix would be needed?

    3.The wall also has a capping that I will need to remake to match in with the existing. Is this a lime concrete?? If so, what is the best way to make this?

    4.What is a good way to estimate the materials needed?

    5. I would look to price this at around £50 p/m labour only - is this reasonable?

    I know there are a lot of questions here, but any advice, tips & thoughts would be greatly received
     
  2. David Hatim

    David Hatim Member

    So are you talking weather struck or weather struck and cut? As big difference in labour time.
    If struck and cut then you will need to use fine sand and a reasonably strong lime mortar, something like NHL2 as opposed to 3.5. The best thing to do is go to a specialist lime mortar supplier, tell them what you are proposing, along with the sqm, they will work it all out and give you a price.
    £50 sqm is okay for raking and weather struck, but not for struck and cut, maybe an extra tenner.
    Can you post pictures of capping?
     
    Abrickie likes this.
  3. Rob Denness

    Rob Denness New Member

    Hi David

    Many thanks for your message.
    Yes, it would be struck and cut with the straight edge.

    Is NHL2 weaker than 3.5? Yes I did try to upload a photo, but the file size was too large. I will endeavour to get one on here.
     
  4. Abrickie

    Abrickie Super Member

    Screenshots are easier to post ;)
     
  5. David Hatim

    David Hatim Member

    NHL2 is stronger, because you will have a thin protruding edge of mortar, it needs to be strong
     
  6. stuart44

    stuart44 Active Member

    NHL 5 is the strongest, then 3.5 and 2 is the weakest.
     
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  7. David Hatim

    David Hatim Member

    My bad! Apologise, I was going the wrong way, thanks for the correction
     
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  8. stuart44

    stuart44 Active Member

    I often get them mixed up myself.
    Bit surprised they want Weather struck and cut on an old garden wall. Tricky job if you have never done it before.
    Need to remember that lime needs more time for mixing. Also needs to be misted for a while.
     
    David Hatim likes this.
  9. Rob Denness

    Rob Denness New Member

    I was going to use 3.5 and mix myself depending on the cost of the premix. If I did decide to make my own what sand and ratio would I use?
     
  10. David Hatim

    David Hatim Member

    2 and a half sand to 1 lime
     
  11. Rob Denness

    Rob Denness New Member

    Will this joint work with sharp sand? Would you still use a churn brush as you would with sharp sand?
     
  12. stuart44

    stuart44 Active Member

    You can't use the churn brush on weather cut as it will wreck it.
     
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  13. David Hatim

    David Hatim Member

    I personally wouldn't use sharp sand, as you may find it difficult to get a neat looking cut
     
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  14. stuart44

    stuart44 Active Member

    The mix that you use will depend to some degree on the type of bricks(eg very soft or hard), the original mix, and the climate and exposure conditions.
    As David has stated, you also need a mix that is workable for this kind of joint. Flush joints hit with the churn brush tend to stay in longer than weather struck and cut joints. You often see them falling out on walls, although it could be down to poor workmanship.
     
    David Hatim likes this.
  15. Rob Denness

    Rob Denness New Member

    Hi, thanks for your reply. I think we might be at cross purposes, because what I meant was would you still use a churn brush before finally filling out the joints for the finishing lip?
    So if not using sharp sand would you go plastering and building sand, or maybe just plastering sand only?
     
  16. Rob Denness

    Rob Denness New Member

  17. Abrickie

    Abrickie Super Member

    OMG look Flemish garden wall done correctly :)
    No brush and just building sand, just an idea if that’s the customers wall just turn the coping around ;)
     
  18. Rob Denness

    Rob Denness New Member

    Thanks for that. Is it acceptable to finish with a weatherstruck & cut in lime mortar? Btw its not a coping, I think its concrete of some sort?
     
  19. Abrickie

    Abrickie Super Member

    Cut and stuck was around well before cement ;)
     
    stuart44 likes this.
  20. Rob Denness

    Rob Denness New Member

    Need some advice on the mix. Where NHL is concerned I have only repaired flint walling:(
     

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