The church i help run has been experiencing problems with salt patches on the tea roon ceiling & walls for a number of years, although the roof has been regularly maintain & looks to be in good repair we noticed the patches on the ceiling expanded during wet weather therefore obviously had a leak. after seeking advice we opted for a foam sealent treatment (cost of 9k) applied inside the loft of which were given a 25yr gaurentee against leaks! However since redecorating the saltpatches remain to be a problem on the ceiling. The decorators assure us they have treated the areas before painting however after retouching up the ceiling the problem reapears? can anyone give me advise as to why this is happening & if there is a solution please?