In the recent heavy rain I noticed that I have a couple of small damps
spots on my newly plastered kitchen wall at around chest height. These
dried out fairly quickly so it is not a major problem.

The outside wall is fairly sound and there is no obvious place that
water could be getting in. My suspicion is that I have a slight leak in
the roof and water is getting in the cavity then getting into the
internal wall via a wall tie or something similar.

In the Spring I intend to do some repairs to the roof, which hopefully
will solve the problem completely. In the meantime, I want to finish
off the tiling in the kitchen. Can the group recommend the best way of
sealing the internal wall to allow me to go ahead with the tiling now,
as I don't want to wait until the spring to finish this.