Advice about tiling in Spain

[PaddyW]

I have contacted the PIV company (Flatmaster 2000 | The Complete Ventilation Solution | Nuaire - https://www.nuaire.co.uk/residential/positive-input-ventilation-piv/flatmaster-2000) and they are very confident that condensation is not the problem and that the DPC (which I installed) is the most probable cause. The DPC installer is coming to see the flaky paint and salt problem in about two weeks time. He attributes the problem to salts coming through the newly re-plastered walls and intends to treat it with some sort of acid wash. I must admit that the more I hear about DPCs the more I am not 100% confident. I can just envisage it emerging elsewhere in the property.

I previously mentioned that the bathrooms will be retiled and hopefully that will avoid salt on the grout in these rooms. Can I just ask for your thoughts on the salt on grout in other rooms. Do you think that raking out the grout and re-grouting would solve the problem. Is there any specific type of grout I should use? Should I use anything else in the gaps before filling with the new grout?

As said earlier I am very grateful to those of you have taken the time to help me.
Muchas gracias
PaddyW

 

[Bond]

Following the installation of a chemical DPC it is good practice to remove any plaster which may have been contaminated with mineral ground salts. Apply a anti-sulphate solution and re-plaster with sand and cement or a renovating plaster , to prevent salts migrating to the surface. Some salts have the ability to absorb moisture directly from the air and liquify on the wall/floor surface, the conditions in which this occurs is in cases of high relative humidity.so even in cases where the primary source of moisture has been successfully dealt with, you can experience a secondary form of dampness, if the salts are still present on / within the wall/floor structure.