We have got black marks (damp/mould) on the outer walls of our two upstair bedroom walls at various heights. This is the gable wall. Yet no signs of damp downstairs...
Been given, and looked in to a few options, such as;
putting ventilation in to the soffits
putting air bricks in both the bedroom (cavity) walls
putting vent tiles in the roof.
to date i have:
taken out the built in wardrobes in both bedrooms and put up free standing,
bought a de-humidifier that i keep in the upstairs hallway outside the 2nr bedrooms,
and have also insulated the loft.
Can anyone advise of the best method to reduce this constant return of damp.
Probably this is caused by either rubble in the cavity or snots of mortar on the wall ties bridging the cavity.
Hire an endoscope, drill a hole in the wall and have a look in the cavity. If you cavities are filled drill very close to the damp patches.
Like to advice you something on rising damp. Rising damp is a problem in which the ground water rises above the masonry walls by capillary action. When the ground water rises above the level, it is than absorbed by the plaster of the walls, which is highly absorbent, thus giving rise to dampness. Due to the problem of the rising damp the plaster began to fall, paint deteriorates and wallpaper loosens. In some worst cases the plaster falls off the walls.
To save the house form this serious problem, we have to repair the moisture sources such as broken pipes, the introduction of either physical barrier using damp proof membranes or materials to form damp proof membranes or materials to form damp proof course or hydrophobic materials as in chemical damp proof courses. The best way to get rid of this problem is to re-plaster the walls and to make the ventilation proper in the building so that the problem didn't occur again. For more you can take an experts advice so that they can guide you in the best way about rising damp. :)
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