I live in a basement flat which previously had mould growing on the walls. the walls were partially knocked down and there was very bad damp. they then put some time of barrier up and re plastered the walls. now there is a new kind of white icy/snow like mould growing and i worry it could be causing damage to the people living in the flat (i.e by breathing it in). can anyone think what kind of mould it is?
2007-01-13 10:28:18 · 6 answers · asked by beckle2000 1 in Home & Garden ➔ Maintenance & Repairs
Calcium deposits from the moisture.
this is a sign that the vapor barrier that was put in was put in wrong.
This will be the first sign of problems to come the next will be mold and rotting of the inside walls.
2007-01-13 10:37:36 · answer #1 · answered by zen522 7 · 1⤊ 0⤋
What you are seeing is called efflouresence. It is a crystaline but very fragile formation formed as minerals are carried out of the cement and exterior soil by moisture- then dehydrated on the inner wall surface. It's not a mold. Not much of a health hazard, except a mess to clean and obnoxious dust when you do.
The reason you get it is that the exterior of the wall lacks sufficient waterproofing, which is why it occurs in old houses where the waterproofing is degrading. Moisture is penetrating the concrete. This is a continuous process that stops only when moisture isn't present in the wall.
It's very difficult to seal off; painting over it is basically unsuccessful. We have controlled it by coating the walls with epoxy (we inject concrete cracks with the same stuff) after a through cleaning. The epoxy stops the water dehydration, and thus the deposits.
Builder/foundation repair contractor
2007-01-13 10:57:23 · answer #2 · answered by spiritgide41 4 · 2⤊ 0⤋
Efflorescence. Concrete is made of three materials, stone, lime cement, and stone. What you are seeing is a chemical breakdown of the bonding agent that holds your wall together. The walls are holding moisture and it will leech thru the wall and evaporate leaving lime deposits. If you have a lot of this problem I would check The perimeter of the house to make sure its graded so water runs away from the house and not towards it. also the leaders & gutters are not dumping the water near the foundation. I use a 50/50 mix of Muriatic acid and water to clean the white lime away and a wire brush. Go buy a good concrete paint for water problems- Glidden oil base concrete or Dryloc concrete paint. Go to your home center, paint store, etc and they will set you up.
2007-01-13 11:11:41 · answer #3 · answered by Rick 2 · 0⤊ 0⤋
Zen, James, and Car are all correct. ALDON co. sells a product called: "Efflorescence Treatment" that should take care of your problem. Preventing future occurrence is another thing... how's your gutters and downspouts?
2007-01-13 11:00:14 · answer #4 · answered by weatherization guy 5 · 0⤊ 0⤋
moisture is wicking the calcium (lime) out of the cement and drying on the inside when the air gets to it. use a wet mop to wipe it off, if you brush it off with a broom it will get airborne and smells nasty. guess how i found out? since you rent, check with your town or city's housing dept. for what your rights are. good luck.
2007-01-13 10:49:50 · answer #5 · answered by car dude 5 · 0⤊ 0⤋
From what you discribed I agree with Zen...
James
2007-01-13 10:39:48 · answer #6 · answered by James 2 · 0⤊ 0⤋