Cost for sorting damp issue? (internal render + plaster)

[Matt..]

I have a small damp issue visible on one wall of my small terrace house. I had someone visit to advise on work today (which shockingly was exactly what i thought was required...). However, i'd like an opinion on what the work should approximately cost to get done.

What i need is a portion of the front wall (~5sq m) stripped back to the brickwork, rendered with waterproof covering, and plastered. Then externally there's a small bit of repointing to do (eg. 1sq m).

Does anyone have a thought on what that would cost to have done?

Also, would it matter if i get the pointing done straight away and before the internal work?


Thanks

[Matt..]

It's an old house without cavity walls. The damp patches on the wall are fairly high up, so it seems like penetrating damp. The wall is mostly stone bricks with a layer of normal brick work between floor levels. The stone has recent pointing, but the brickwork has visible holes. It seems that the water enters here and moves down the wall. Hence looking at sorting the pointing and then fixing the internal rendering/plaster.

[Matt..]

How can I tell if the reprinting used cement or lime?

[Matt..]

The plaster has blown in one very small area. However, there are patch stains elsewhere on the wall. But it's only one part of a single wall.

One other point is I have some cheaply humidity sensors from Amazon and they show the house to vary between 50 and 70% humidity. 70 seems very high. However, I do wonder if that will reduce once colder weather comes.