I have been trying to combat a damp patch on my wall by my door for a couple of years now. It does not go as far as the front door frame, It does not come from the ground either. It does not come from the radiator. I am positive it comes from a post which is bolted to the outside of the house which has a gate on it. Can anyone offer any advice please how I can remedy the problem. Will I need to take the post, gate and fence panels out to sort it or could I just remove the bolt and squirt some outside sealant in there to seal it and re-insert bolt and use a de-humidifier to dry out damp patch?. Any help would be really appreciated . Thanks.
The bolt is the cause of the problem. Steel is a very good conductor of heat, and as both heat and water vapour always move to cold, the bolt is acting as a conductor of your heat to the outside and because the bolt is colder than anything else in the room all the water vapour in the room is making its ways to that cold area of the wall. Solution, remove the bolt and fill the hole with spray foam.