Advice in repointing and spalled bricks below damp course

[mylesw]

Hi there

Just after a bit of general advice.

Since moving in to our new house last summer, I've become increasingly aware of the condition of the bricks below the level of the damp course and wondered whether this should be a cause for any concern. I've attached some photos. I appreciate that it may be difficult to advise from these, but the bricks are badly spalled in some areas and their condition (and that of the mortar in these areas) is, I would say, generally poor.

It would appear to me that some areas of the brickwork have been repointed at some stage after the buildings construction with cement based mortar. I am wondering whether a building of this age (built circa 1935) should have in fact been repointed with a lime based mortar, and it is the use of cement mortar that is causing the spalling. Is this a possibility?

You will see from the attached photos that a particularly thick layer of cement mortar appears to have been applied along the top of the damp course for some reason (i.e. in the photo where the cable runs along the bay). Does anyone know why this has been done like this (i have seen it like this on other properties) and could this be causing the spalling of the bricks below the damp course?

I'm planning on repointing the affected ares as best as i can before winter. Does anyone have any advice on the type of mortar i should be using? Is there any downside to just using a lime mortar in any event?

Any advice gratefully received.

Many thanks

 

[stuart45]

At the time of your original build OPC was becoming more commonly used in mortar. Usually it was gauged into the lime mortar, until later years when it was used alone. Your house looks like it has been repointed at some point.
Because the DPC joint is often quite a large joint(especially if 2 courses of slate has been used)that method of pointing it up was often employed.
A 6/1/1 sand/OPC/Lime mix would probably be OK(although nowadays a stronger mix is used below DPC on newbuilds). You could also replace a few of the worst bricks.