Advertisement
Help Keep Boards Alive. Support us by going ad free today. See here: https://subscriptions.boards.ie/.
https://www.boards.ie/group/1878-subscribers-forum

Private Group for paid up members of Boards.ie. Join the club.
Hi all, please see this major site announcement: https://www.boards.ie/discussion/2058427594/boards-ie-2026

Rusts stains in Plaster

  • 16-10-2016 07:08PM
    #1
    dootv
    Registered Users, Registered Users 2 Posts: 32 ✭


    A few years ago my chimney had a problem with letting in rain but after a local builder re-flued, re-rendered the exterior of the stack and fitted a conical metal cap over the chimney, the problem was solved. Until this, the plaster-rendered interior part of the chimney stack in the room below would be completely soaked, as would the plasterboard ceiling above.
    I have had a problem ever since with a rust stain that comes through the emulsion whenever I try to repaint the chimney stack in the room below. There appears to be a sort of metal mesh around the chimney stack over which the plaster is rendered, and this seems responsible for the chronic rust stain problem. I have even tried removing the plaster down to the mesh, replastering the affected area with proprietary filler, and repainting - only for the rust stain to be back a few weeks later.
    Would be grateful to any board members who might have a solution to permanently suppress the rust staining. Thanks.


Comments

  • #2
    Who2
    Registered Users, Registered Users 2 Posts: 2,290 ✭✭✭Who2


    There's a stain block paint made by zinnser, paint this on first then go from there, otherwise remove the mesh.


  • #3
    dootv
    Registered Users, Registered Users 2 Posts: 32 ✭dootv


    Thanks Who2. Looks as if the stuff is stocked all over the place in Ireland. Seems from the specs its exactly what I need.


  • #4
    Ceepo
    Registered Users, Registered Users 2 Posts: 2,980 ✭✭✭Ceepo


    dootv wrote: »
    Thanks Who2. Looks as if the stuff is stocked all over the place in Ireland. Seems from the specs its exactly what I need.

    Oil based undercoat will do the same thing if you have some.


  • #5
    CJhaughey
    Registered Users, Registered Users 2 Posts: 14,670 ✭✭✭✭CJhaughey


    Rusty mesh will end up causing the render to fail anyway as the rust swells and bursts it.
    I'd do it again properly and use fibreglass mesh if you can.


  • #6
    dootv
    Registered Users, Registered Users 2 Posts: 32 ✭dootv


    CJhaughey wrote: »
    Rusty mesh will end up causing the render to fail anyway as the rust swells and bursts it.
    I'd do it again properly and use fibreglass mesh if you can.
    Ok, thanks, could be getting a bit beyond my "expertise" though!


  • Advertisement
  • #7
    TheLastMohican
    Registered Users, Registered Users 2 Posts: 1,837 ✭✭✭TheLastMohican


    dootv wrote: »
    CJhaughey wrote: »
    Rusty mesh will end up causing the render to fail anyway as the rust swells and bursts it.
    I'd do it again properly and use fibreglass mesh if you can.
    Ok, thanks, could be getting a bit beyond my "expertise" though!
    A few pics would shed some light


Advertisement
Advertisement