damp? plaster gone powdery?

[chrispollin]

hi guys, we are now on with decorating our main bedroom, and think we have a small damp issue. one area has some mould on it, but next to it, it looks like the plaster has gone powdery???

firstly what is this and why has it gone like this?

and what can i do about it?

 

[handyman77]

I would hazard a guess and say that its bonding plaster that is damp. You need to hack that off and render. (if its a solid wall!)

 

[joe-90]

You need to sort your damp issue first.

 

[chrispollin]

from what i can see outside, the previous owner of the house, has raised the drive and patio - unfortunately - and where this damp spot is there is only 1 course between the damp course and the slabs...

whats the best remedy for the damp?

 

[tim00]

1. As has been said above:
2. hack off the degraded plaster and remove the skirtings(examine the skirt backs). Render 4-1-1 in S&L&C or 3-1 S&L.
3. Is it a solid or cavity wall? Solid or suspended floor?
4. All this and much more if you research these issue on the Building forum.

 

[chrispollin]

hi there, its a cavity wall, its also a solid floor.

Apparently it has also had injections into the wall about 8 years ago.

can you explain what these stand for?

Render 4-1-1 in S&L&C or 3-1 S&L

be gently im a beginner lol

 

[tim00]

1. Research will explain much.

2. In theory, even if a cavity wall's outside skin has no DPC it should not affect the inner skin. However, the cavity may be blocked - remove a brick or two from inside when you hack-off, and examine the cavity for bridging.

3. Chances are that the Damp company never rendered the interior, merely used browning or bonding. Many injection fluids will actually degrade the existing DPC.

4. sand, lime cement in those proportions.

 

[Primer]

1. As has been said above:
2. hack off the degraded plaster and remove the skirtings(examine the skirt backs). Render 4-1-1 in S&L&C or 3-1 S&L.
3. Is it a solid or cavity wall? Solid or suspended floor?
4. All this and much more if you research these issue on the Building forum.

And make sure you weigh the sand and lime. The sand needs to be bone dry and clean. If you don't weigh it dry your mix ratio will be out.

 

[bonditman]

And make sure you weigh the sand and lime. The sand needs to be bone dry and clean. If you don't weigh it dry your mix ratio will be out.

damn ive just ordered 2 tonnes of plastering sand and its damp, should i wait for it to dry out and tell the plasterer to come back in a couple of weeks? i dont want him weighing it wrong, or should i tell wickes to take it back and send me some bone dry sand?

 

[stevethespreader]

And make sure you weigh the sand and lime. The sand needs to be bone dry and clean. If you don't weigh it dry your mix ratio will be out.

damn ive just ordered 2 tonnes of plastering sand and its damp, should i wait for it to dry out and tell the plasterer to come back in a couple of weeks? i dont want him weighing it wrong, or should i tell wickes to take it back and send me some bone dry sand?

ilmao

 

[huddsspread]

1. As has been said above:
2. hack off the degraded plaster and remove the skirtings(examine the skirt backs). Render 4-1-1 in S&L&C or 3-1 S&L.
3. Is it a solid or cavity wall? Solid or suspended floor?
4. All this and much more if you research these issue on the Building forum.

And make sure you weigh the sand and lime. The sand needs to be bone dry and clean. If you don't weigh it dry your mix ratio will be out.

Now you are taking the **** mate. Weighing your mix?

 

[Micilin]

Mixes are done by volume - best way to ensure correct mix is by buckets expecially if the colour of the mix is to be uniform - perhaps if not painted, or the butter coat for dry dashing.

Using bags, easy to work out ratios

In practice, once your initial mix is sorted, its a case of knowing how much sand to a half bag of cement(or bag etc) and /or lime and filling the mixer to that level each time.

Wet or dry sand just means les or mare water added.

Bone dry sand? Apart from kiln dry sand for block paving I think sopmeone is having a little laugh??