Dampness in garages is a very common issue home owners tend to face and there are a few different reasons this may be happening. Finding and fixing these issues should be high on your to-do list to protect any items stored in your garage and prevent mould.
A rising dampness typically is visual moisture on the lower parts of the walls and floor. This is due to moisture rising from the ground. Most newer properties have a water proof barrier and membrane under the flooring so this could be damaged. In older homes, it may not have sufficient waterproofing on the floor so you can consider calling a professional to assess the best options.
A penetrating dampness can happen in any part of the garages and is typically do to waterproofing damage in a specific area. This could be due to damaged guttering, missing tiles or bricks losing their waterproof coating. Corners and joints are also common problem areas. Identifying and remedying the weakness, should solve the problem.
Condensation is another way moisture may be present and is typically prevalent in environments that are not properly ventilated. Installing an extractor fan or regularly airing out your garage could significantly reduce the amount of dampness you experience.
Other ways of keeping out moisture, are ensuring any windows are double glazed and by drying any wet items before storing them in your garage, including vehicles.