Pointing

Discussion in 'Builders' Talk' started by Ghost from the past, Aug 1, 2017.

  1. Just chopped out the crappy pointing on my slabbed patio. Can anyone advise the best way to repoint. Do I mix up the sharp and cement mix dry, sweep in then damp down and trowel in, or mix up wet and trowel in? I know what I'd sooner do but what's best.
     
  2. Mix up wet, but not wet.

    Brush out the grooves well, and spray-dampen if it's absorbent.

    Then mix up a stiff mortar - not in the least bit 'sloppy'. Get some on to your upside-down trowel and run the blade edge along the bottom of the pointing gap, pressing the mortar in firmly with your pointing tool. Keep going.

    Then, when you know it's stiff enough - 10 minutes, 20, 30, whatevs - firmly run your profile along t'grooves - the excess mortar will be extruded and will mostly fall away in a crumbly-mortar manner - it certainly shouldn't be so sloppy that it sticks to the bricks. If you are left with sharp mortar ridges along the brick edges, use your trowel sweeping up and down over the bricks to remove. Or just wait a day and brush off.

    But the 'secret' - as much as there is one - is to not use a sloppy mix that'll stick to every surface it touches.
     
    Ghost from the past likes this.
  3. Astramax

    Astramax Super Member

    Some folks say dry/damp others say moist ;)
     
    KIAB likes this.
  4. chippie244

    chippie244 Super Member

    I like moist :)
     
  5. Astramax

    Astramax Super Member

    Be careful not to stain your slab as can happen if over moist also it is known this will be difficult to remove once thoroughly dry.
     
    Ghost from the past likes this.
  6. Absolutely - that's why it has to be a stiff, moist mix. Almost 'crumbly' in texture, but when you squish it it binds nicely; it should be easily workable so's it can be finished off neatly and smoothly with a former, but water shouldn't ooze out of it when worked with the tool.

    When the excess is forced out of the pointing lines when firmly running the former along it, it should either fall away cleanly or else leave raised tram lines either side on the brick edges which can then be scraped/brushed cleanly away (after being allowed to stand for a while until you know it'll do this cleanly). Even if any lands on the brick surface, it shouldn't stain it - unless you actually wipe it over the bricks.

    Beware if spraying water in the grooves - any that lands on the brick faces will then make it prone to being stained if the mortar also goes on there. In fact only spray if you think there's a real risk of the bricks (eg if they are old) being particularly absorbent.

    Give it a bash, Ghost - it'll make complete sense when you do it.
     
    Ghost from the past likes this.
  7. P J Thompson

    P J Thompson Active Member

    Probably not going to be popular but I did one with a resin premix a few months back, it was an absolute p of p to do compared to proper pointing and according to the client it actually did go off properly and is tickety boo thus far.
     
  8. Is that injected in using a cartridge or air-driven gun?

    How is it finished off?
     
  9. P J Thompson

    P J Thompson Active Member

  10. DIYDave.

    DIYDave. Screwfix Select


    Done a bit of patio laying and refurb myself over the years and always take advice and mixes from 'Paving Expert' - great site online and endless information

    I've used their 'recipe' for slab pointing and it uses soft / building sand, not sharp
     
  11. Thanks guys for the information Am a bit surprised at DIY Dave at using pit sand but it all gives me something to chew on. Great.
     
  12. Dr Bodgit

    Dr Bodgit Super Member

    Blokes used kiln dried sand on my big patio years ago, mixed it up quite wet and squirted it in with a kind of icing gun if you know what I mean.

    Otherwise as DA says, nice dry mix (water added but minimal amount). It will attract water over time anyway so drier the better IMO.
     
  13. stevie22

    stevie22 Screwfix Select

    Get the mix damp so it will just bind together when you squeeze a handful. You want it as wet as you can get away with so you have enough water to hydrate the cement. I like at least 50% sharp sand. Brush into gaps, iron in, top up and repeat as required. Water the joints after a couple of hours and keep them damp for a couple of days.
     
    Ghost from the past likes this.

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