Cavity wall cleaning can often help in properties where there is a cavity wall but the wall seems to have rising damp, this can be caused by debris in the cavity that is bridging from the outer skin of the property to the inner skin. It can take decades before the debris in the cavity becomes a problem but cleaning it out can be a better solution than having a damp proof course installed. If you are getting damp patches all over your walls after having cavity wall insulation installed then you may need to remove the cavity wall insulation.
To start this project you need to remove a brick or two from the wall, it's quite safe to remove one or two bricks from a wall at the same time but never remove more than two bricks at the same time. If more bricks need removing at the same time you should consult a professional builder or surveyor. For instructions on removing a brick please see here- Removing a brick For this task it is best to remove one or two bricks at (or close to) floor level from inside of the property.
This is a picture of inside the cavity, you can see that there is considerable debris, which can cause damp to travel from the outer skin of the property to the inner skin. Once a brick has been removed you can use a digital camera, mobile phone or camcorder to survey the cavity by taking pictures with the flash on- just make sure you do not drop it!
Once a brick or two have been removed at (or close to) floor level you can scrape out debris using your hand (wearing gloves)
Once you can no longer reach debris you can then use a selection of tools to scrape the debris towards the hole, here we are using a metal bar. A drain rod with a scraping attachment on the end is excellent for this, providing it will fit in the cavity.
You can also vacuum the cavity using an old vacuum cleaner, this is good for removing any small particles once the majority of debris has been scraped from the cavity. To replace the bricks please see the project on installing an air brick as this shows how to replace a brick/air brick