Single brick garage damp wall

Hi
I hope somebody could give me some advice. I am converting my single garage to an office. I have boarded and insulated where the garage door opening is. This has been newly plastered. The external wall of the garage is single brick. It already has been plastered by the last owner. The outside has been rendered. I have as small amount of condensation/ damp at the bottom of the wall. No mould just feels damp. My plan is to get a de-humidifier to dry the area out. My idea is then to put waterproof sealant on the render outside so water can't penetrate. I will have heating put in their so the room should be warm through the winter months.
As it is a single garage I do not have the room to build a cavity as we also have the washing machine and tumble dryer in there, so space a premium.
Does this sound correct?

Many thanks Andrew

Hi Andrew,

Putting waterproof sealant on the render outside might not stop the damp, as if there is no damp course installed the damp will travel up through the bricks.

I will suggest 2 things: You could get all the inside walls tanked, which is normally used for basements, this will stop the water ingressing into the room and then apply insulated plaster board. You must use insulated plaster board, as this will prevent condensation as well . I have done this before on a single brick room and it works very well. The only downside with this you will not be able to drill into the walls, as this could prevent the tanking from working, where the drill holes are.

Or you could use a damp proof paint not one from a local diy store! called Dryzone: dry base liquid application, which is normally used to damp proof floors, but i have used it on walls and it works really well and can be painted over. Just type in dryzone in a well known search site and you will find all the information out about it.

Hope this helps any questions, just ask. Im not a builder by trade but my hobby is renovating old houses, so i have a lot of experiance of dealing with damp.

Dave.

Thanks Dave, that's is a great help. I will be drilling for shelves and storage so I will try the dryzone paint. Thanks again for your help.
Andrew

Ok i will still suggest to get the outside waterproofed and rendered. Hope all goes well.

If you have a good render on the outside and you have painted it with good paint then you should have no problems with damp. I think all your problems are internal you should put some air-bricks in get a good air-flow Why not get a window fitted even if it is frosted glass and away from every ones view.

Hi Andrew,

Did u sort out your gargage wall? If so how did you go about it? if you dont mind me asking.

Dave.