What is the best thing to use on damp walls to clean them

What is the wall made from? Is it something like cement or concrete that was never sealed? Is it damp on the outside too? If it's damp on all surfaces there has got to be a reason. Houses aren't usually built with materials that encourage excess dampness. Click on this article and see if it helps. You may need more than a paint job because paint will peel if it gets wet. Wishing you the best & Happy New Year!

https://www.mybuilder.com/questions/v/16184/penetrating-damp-on-rendered-gable-end-wall-in-victorian-end-of-terrace

I would be concerned if there is a leak coming from somewhere or the possibility or mold or mildew before anything else.

If the wall is always damp, then you have a problem that you must resolve. Interior Sheetrock should never be damp. Start by investigating the outside first for any openings permitting moisture to get in. Pay particular attention to where the roof meets that wall. Also, be sure that any gutters in that area are draining fully to the leaders. If you are sure that everything is sealed externally, could it be that this wall was never insulated internally. Start by punching a small hole in the wall that is easily repaired with plaster. Inspect the interior of the wall. If no insulation is seen, then you have found your problem which will required you to rip open the existing Sheetrock and properly insulate that wall. Be sure to pay attention to the vapor barrier side of the insulation and install properly. Then you can re-Sheetrock the wall, tape and compound and put two coats of primer on the wall before painting. If you are going to wallpaper, be sure to use a coat of wallpaper special primer. Seems like a great deal of work but it really is not and will be well-worth your effort. Good luck. ...Joe

Sure you don't have a leak somewhere? I would check the attic rafters, sofits and insulation for moisture stains, and around windows and sills on that side of the house.

Have you tried using a dehumidifier in the room? The other thing is maybe that wall was not insulated. I had a wall like that when I moved into this old house, and the second year I insulated it and no more problems.

Another source of your moisture could be gas appliances like a heater, dryers, stove that are improperly vented and this could be very dangerous. Get them checked immediately.

I know there is a moisture barrier paint for cement. You might want to see if there is a roof leak, out insulate the wall better

I agree with Jasciu. Sounds to me like the wall is not insulated. The moisture is probably condensation from a warm room and cold wall.

The question should be "How do I get rid of the dampness in the wall"? That can be the beginning of respiratory problems and/or mold. Is there a leak in the roof? Lots of things can cause the dampness. Once you get that corrected - your question will also go away as you can use any kind of good quality paint you wish.

thank you , to everyone for taking the time to answer my query , I had a builder check the roof ,and all guttering is clear , the house isn't insulated as its cavity blocks that were layed in such a way that they can't be filled , I may have to resort to having the wall dry lined , all the windows are in excellent condition with air vents , the room directly above is fine , so it's not a roof problem , I had concidered having the house wrapped on the outside , but I have heard conflicting views on this method , ,I will take your ideas on board , thank you again , and A HAPPY NEW YEAR TO YOU ALL ,