New damp proof, salts appearing

[JohnnyF]

Hi,

We live in a Victorian terrace and when moving some furniture noticed a small patch of effloresence coming through the plaster. A damp company confirmed we had damp so 2 weeks ago we had the plaster removed on a 4m width of wall, injected and then replastered to about a metre high. The base coat went on one day and skimmed the next.

We went away on holiday the next day and just come back and a good 1.5m wide area is now showing sporadic bits of salt.

Is this normal? When we've had damp work before we never had this happen.

If normal will the salt not damage the skimmed finish and need redoing? We were told to leave decorating for 6 weeks, is it best to leave longer if salts appearing?

I'll ring the company on Monday but just wanting peace of mind before then. Cheers for looking

 

[^woody^]

A damp company confirmed we had damp

Lol. I bet they did.

They may have used the wrong plaster, or not done done the job properly. Salt stains in plaster are bad.

 

[ree]

As above.

Do you still have the D&T companies inspection report where they "confirm" that you had damp?
Did they say why you had damp?
Did they specify what plaster/render they would use in the remedial work?

 

[kazuya]

did they paint the wall with at least 2 coats of bitumen or similar before they re-plastered, did they use plaster or did they use a sand and cement render?

 

[JohnnyF]

The report said rising damp and just that it would be re plastered to the re plastering specification. Doesn't say what though but they seem a reputable firm and came recommended.

Not sure on type of plaster used or if painted in bitumen.

So basically salt shouldn't be showing if done properly and since it is, it will reduce the quality of the skimmed finish? Have I understood that correctly? Just wanting to be sure I don't get fobbed off when I ring them tomorrow that it is part of the drying out process.

Cheers

 

[ree]

With respect, you still haven't answered two of the questions i asked?

Never paint a damp affected wall (internally or externally) with bitumen. Or you will only cause further difficulties.

If you have a guarantee then the re-plastering specification is part of the guarantee - hence, they must give you the specification for materials and installation.

Salt penetration, as mentioned above, is bad - very bad. Indications are that they used gypsum plaster not render.

 

[kazuya]

With respect, you still haven't answered two of the questions i asked?

Never paint a damp affected wall (internally or externally) with bitumen. Or you will only cause further difficulties.

well ill have to disagree with you there, done it lots of times including my own house 24 years ago without any problems at all
as long as its done properly that is

 

[Joe Malone]

With respect, you still haven't answered two of the questions i asked?

Never paint a damp affected wall (internally or externally) with bitumen. Or you will only cause further difficulties.

well ill have to disagree with you there, done it lots of times including my own house 24 years ago without any problems at all
as long as its done properly that is

You can disagree all you like Kazuya but you're wrong. You should not apply anything to walls because they need to breathe in order to manage moisture. If you have wall base damp you need to make a decision between whether you want to manage or cure the damp. Retrofit DPC injection and re-plastering with renovating plaster is nothing more than a management solution, designed to dam in the damp behind a waterproof layer. It gives the appearance of a dry surface and an illusion that you have resolved your damp problem when in fact you have made it worse. If moisture can't evaporate from the wall base then it will rise even further up the wall. I have posted a Youtube clip that I posted, which shows precisely what happens when you choose to manage rather than cure the problem.

 

[Joe Malone]

I'll also point out that the rising damp demonstrated in these clips is not true rising damp, it is what I call induced rising damp because it is caused by human intervention.

 

[kazuya]

oh right its on YouTube so must be true