How do I solve moisture issues in old brick walls?


how to solve moisture in old brick walls that are covered with knauf boards. the humidity rises to 10-15 cm from the floor 6 months after the walls are laid. before that there were ceramic tiles and below them about 5 cm thick and no moisture was coming out.

  7 answers
  • Johnavallance82 Johnavallance82 on Aug 25, 2018

    Hi Nike, Where are these walls, are they double walls with a damp course or are they an old cold conservatory or an outside toilet? They should have used a bitumen lining at least, if not built up an inner wall and used insulation. .............

    • Nike Nike on Aug 25, 2018

      Thank you for answer!

      The wals are in my bathroom in 200 years old building in Old town and on ground floor.

      They said they put the bitumen on the floor and up to the wall at a height of 1 meter but I doubt it. Then they put knauf walls with spacing as air isolation.

      What kind of isolation it should be?

      But is there a way to make this problem more painless so I should not bust down to the bricks?

  • Johnavallance82 Johnavallance82 on Aug 26, 2018

    Hello again Nike,

    Sadly No easy quick way to do it! Call or an Architect and have a proper Survey done or a Building Surveyor. It probably needs to be taken right back to the brickwork otherwise the problem will be on going! Sorry I can't give you that quick fix! Good luck and best wishes.....

    • Nike Nike on Aug 26, 2018

      Thank you again for your answer John! Unfortunately, I was afraid of that. Works were carried out by a construction craft, my friend, and they ended 7 months ago. Everything is new, they really fooled me. Thanks

  • Johnavallance82 Johnavallance82 on Aug 26, 2018

    Hello again Nike,

    Have you called them back in again to right the problem. I think because your home is so old you are have solid wall without a damproof course. It is go back to the bricks. Best regards..........Ask the original people to bring their damp meter with them to give technical proof of what is obvious.........

    • Nike Nike on Aug 29, 2018

      Hello John!

      Thanks for your advice I can try it ... but I do not hope very much that the first people will fix it, Obviously they are not professionally.

      I did not understand the part of moisture returning to the bricks. Can you clarify?

      Forgive my bad English. Best regards

  • Johnavallance82 Johnavallance82 on Aug 30, 2018

    Hello again Nike,

    Is this damp problem only in the Bathroom? If it is then it might be lack of enough ventilation, too much moisture or hot air building up in a closed room.

    You must have Ventilation via Extractor Fan and or Window, otherwise condensation will run down windows and walls and land on floor and cause rising damp If that is your problem then put in a good extractor fan and open the window to let steam out! If the problem is not solved it can only get worse........

    • Nike Nike on Sep 03, 2018

      Hello John,

      First I'll try the simplest, easiest methods as you have suggested.

      I have a window in the bathroom that is continually semi-open but on the side of the park with trees, there is moisture in the air too, so I put the grid on the door of the bathroom additionally. Sometimes I open them and make the plow. That was not enough, however, the problem of moisture I described before stayed, so I intend to break the wall opposed to the window (a hole with a grid), into a storage room that has a window on the opposite side of the building, so the air would flow constantly. Is it okay if I put this hole under the ceiling?

      Also I wonder if a couple of holes with grids above the floor on the problematic wall help to ventilate the space between the knauf and the wall?

      Thanks for your advices and time.

  • Johnavallance82 Johnavallance82 on Sep 03, 2018

    Hello again Nike,

    Before you go doing anything to drastic, can I ask if the Knauf walls have had anything put on top of them Knauf boards are a form of Plasterboard and should not be left unfinished. If you haven't done so, you ought to cover the walls with ceramic tiles on a waterproof adhesive and grout or Plexi glass sealed with waterproof sealer. Yes you will still need to have good ventilation. Do get a Qualified Building Surveyor to take a look at the room and give his recommendations and advice as to how you should proceed. You need someone qualified on the spot to advise you. I feel I can't help further as I live in the UK.

    Very best wishes, I hope the problem is resolved soon.........

    • Nike Nike on Sep 07, 2018

      Thank you very much for your help so far. I'm still looking for a professional person to look at that wall and it's a bit harder because I live in Croatia. :)

      Best regards

  • Agnes Chrzanowska Agnes Chrzanowska on Dec 31, 2020

    You can replace them that might help

  • Lifestyles Homes Lifestyles Homes on Jan 02, 2021

    In the States we have a proven

    masonry sealer called Red Guard. I’m sure there’s something similar in Croatia.

    The above-noted suggestions point to a common thread:

    determine where the moisture is coming from, stop the source, dry it out (might need to treat it for mold too) and then replace the Knauff Boards (as mold can grow in them).

    Not a good time of year to be doing this. Good luck.