Damp Brickwork All manner of questions and solutions to problems and issues surrounding the subject of brickwork, blockwork and stonework

[chrishogg7]

I had a leaking roof which has now been fixed and also a leak at one of my windows which has also been fixed. My wall was very damp and I have removed the lath and plaster and hired an industrial dehumidifier. I am into the 4th week and have removed 302 pints of water so far but am still getting about 14-15 pints a night. I have also put up a fan which is running 24/7 as well. Can anyone tell me what sort of length of time it takes to dry bricks and mortar please. Is there anything else I can do in the meantime.

[Perry525]

A wet wall or floor will usually dry at the rate of 1mm per 24 hours.

This, where the surface is exposed and the air is dry.

If you have solid walls, they will equal about 10 inches, that's about 250mm = 250 days.

A cavity wall about 5 inches, 125mm = 125 days.

In the normal way, the passing wind, will tend to speed things. As will the hot sun (Not that there has been much of that recently)

We have had a lot of totally saturated days for the last 6 weeks or so, with reading of 99% humidity, this will not have helped.

As you may have realised from using your de humidifier, water vapour always moves from hot to (the) cold coil in the de humidifier, that should indicate that keeping the room and wall temperatures warm and steady will help to move the water from the walls to the de humidifier and or through the walls to the colder outside.

Warm air can hold a lot more water vapour than cold.

Turning the heating down or off overnight or, at any time will slow progress.

If you have the fan blowing on the wall, it will help to blow warm air onto the wall and increase the rate of extraction or help move the water from the surface further into the wall. Other wise it is doing nothing.

May I suggest that you buy a hygrometer, complete with memory, and a damp meter that you can check every day for progress