Walls Still Damp

Verb

I had a chemical DPC installed 2 years ago but only decorated 8 months ago and still getting a damp looking tidal mark on the walls, they never removed any plaster at all, which I now believe is a big no no. I have just had the company back and being told the following if anyone can point me in the right direct as to if they are spinning me a line or not.

1. Plaster was not removed as this is always not necessary

2. The tidal mark is just the salts coming out the wall (still 2 years on)

3. Sand the wall to remove the paint and see if the mark comes back

4. Still getting damp readings in the areas that where treated of 27.9 up to 73.5 

5. They have told me that there will always be readings of damp in these walls

6. Had the walls been tanked and plastered would the damp readings be normal?

7. They only looked at the 3 areas I pointed out as that is what they do they don't examine the whole house as a matter of caution

What would any professional damp proof specialist be doing now and what should they have done previously 

the_lunatic_is_in_my_head

Verb said:

5. They have told me that there will always be readings of damp in these walls

Says it all really. The general view here, which I agree with, is that such work carried out by damp companies doesn't solve the problem and can make it worse.

Which walls are affected by damp, internal or external? Any signs of problems outside such as broken gutters, downpipes discharging into the ground next to the house, raised ground levels outside or anything leaning against the house?

Verb

The main wall is the bay window wall but the other is the hall that joins to the garage.

There are no issues with gutters or raised floors as I've had this checked by a second company.

My real question is. If they had removed the plaster and tanked or treated the wall before plastering again would I sill get damp readings

stuart45

Most firms hack off and replace the plaster back to the brickwork. This tends to hold the damp in the wall back for a while, although in time it may crack and allow damp through. 
What type of wall is between the house and garage? e.g. Cavity wall, 4 inch brickwork?
It could also be condensation.

Verb

There is a cavity but its a 1930s house

FreeBear

Verb said: 4. Still getting damp readings in the areas that where treated of 27.9 up to 73.5

What would any professional damp proof specialist be doing now and what should they have done previously

They using one of those protimeters with sharp prongs on on end ?

If so, they can only give a proper reading when used on untreated wood. Walls & plaster will contain a whole host of chemicals that will render the readings meaningless. For example, any white powdery deposits forming on the wall - That will be various salt compounds which will make a huge difference to the readings. The only reliable way to get an accurate measure of moisture in a wall outside of a lab is to use a Carbide Meter. That said, in the right hands, and with a modicum of experience, an electrical protimeter can help in highlighting areas that might be suffering from damp. A well trained surveyor will than be able to look at the building as a whole and recommend remediations to fix the root cause (and injecting chemicals in to the walls won't be one of them).

Unfortunately, "professional", "damp proof", and "specialist" should never be used in the same sentence - The whole industry is geared up to selling treatments to mask damp problems without curing the root cause.

Verb

Without naming names. The company who did my survey and work is a national company, that in part is why I went with them. I think my real issue is from the survey and surveyor. I had no clue about damp issues that is why I called in the elegit professionals. I'm fully versed now on the British Standard for damp treatments and this company has fallen well short.

I'm now playing a tactical game with them. This question I've posted is off the back of there Regional Manager coming out earlier this week.