res stains bleeding out from exterior walls

Hi ,were thinking of buying a 20 year old detached house.However we noticed a red staining on the gable endof the houses.Its onother houses on the road were buying on .the exterior is pebble dashed.A local man said its weathering? dont understand this.Does anyone know the cause of this?how can it be treated if at all? it spoils the look of the house but were more concerned as to the cause .

Its a type of fungus and is really of no consequence other than the cosmetic effect. Can me treated chemically with Mosgo/Mossbuster and several other chemical which is stocked in hardware shops. Generally is more prevalent on the west side. If you had more dry weather it would not be as prevalent. Has nothing to do with the inside of house. Very common.

thanks dermot,any idea as to the cause? Can it penetrate the house?

This not a scientific explanation of it but in general it is caused where the walls do not get an opportunity to dry out. You will find that it is most prevalent in dry dash houses and plastered houses which have not been painted. You will often notice in on chimneys which are often left unpainted because of the difficulty of painting them. Normally worse on the west side of the house as sun etc shines less thereby not drying out as will during the day. No it will not penetrate the house. I vaguely remember someone mentioned to me about a sealer which you could spray on after you had removed the red fungus. It is unsightly but in the end it is cosmetic. I certainly would be more concerned about mould on the inside of the house. Presentation wise seller is not doing themselves any favours
any you might get it for less because of this. If that was the only negative it would not concern me. Best of luck to you.

Not so much red - as white !

Have noticed our red brick walls, and our neighbours', seem to have what looks like a chalkish residue over last two weeks only. I had initially thought a handyman wiped his brush clean on the wall only to notice it higher up on my own, and on neighbours' houses.

What is this, and will it wash off in time, or should I do something ?

I think what you have there Kildavin is what is known as Efflorescence which is caused by dampness coming out of the brick system and contained in the dampness is salt from the building materials which appears as white when it dries out on the surface. You see it quite a lot on new and relatively new brick work. I have a feeling that the wet weather can cause it too. I am presuming that there is no water getting into the brickwork other than normal rainfall hitting off the brickwork. You could wash it off using a firm brush. Sorry about the poor explanation.