re-pointing and Damp

[cheadle123]

Can anyone help? I am new to the forum and have little to no knowledge of masonry repairs.
I live in an 1850’s (Victorian) cottage in Chester which in 2003 and was both extended and re-pointed in the original “Cheshire” brick. I have noticed on my south facing wall that the mortar below the backdoor threshold has totally decayed / crumbled. It appears that the mortar that has crumbled is below the PVC damp sheet but in a few areas it appears the mortar above the PVC membrane is wet.
How can I repair this issue? Is it normal for the mortar to decay below the damp proof PVC Membrane line?
I guess with the house being so old the mortar is a lime mix? If so, what does this mean about the condition of the foundations?

Just for the sake of clarity. Given the house age of 150 years and therefore I think lime mortar has been used, does this mean the foundation mortar is decayed / crumbled? What sort of foundations did houses of this age get built on? Should I be concerned?
I noticed that the builder in 2003 re-pointed the house in a cement mix (I guess over the original lime mortar) and spray coated the brick with clear sealant (but has added breathe holes / grids at the footings).
I have not noticed any crack / subsidence but when I went to mount and external light about half way up the wall when I drilled into the mortar it was very easy (not damp) unlike when you drill cement mortar it is harder to drill. Is this because the mortar is a lime mix and therefore easy to drill?
What signs should I look for by way of damage with regard to the builder in 2003 re-pointed the house in a cement mix (I guess over the original lime mortar) and spray coating the brick with clear sealant ?

Any help / advice truly appreciated.

 

[Moo]

What sort of foundations did houses of this age get built on?

Others on the forum are far, far better qualified than I am to give expert advice about foundations, but I think I can state with some confidence that houses of this age did not have PVC damp membranes.

 

[Tom]

I read it that the OP meant the extension had a DPM. Maybe not. I wonder if they meant a slate course?

Jaqy

 

[cheadle123]

I know houses of this age did not have a DPM but what I cannot understand is that you can see the DPM sticking out of the pointing> So I guess the builder in 2003 must have either re-built the walls? Or some how cut the pointing and added the DPM?
That aside any answers on the other questions?
Thanks

 

[biffvernon]

It is physically possible to cut out a layer of mortar, insert a plastic dpc and then repoint. You either do it very quickly, or a couple of feet at a time.

 

[Raylea]

My father in law was telling me once about cutting out the pointing and adding a dpm, he said it was a long job.

Of no help just got me thinking

Raylea

 

[NT]

Pointing deteriorating and falling is out normal behaviour. Hence repointing is needed at times. Lime mortar should be used to avoid damage. Old pointing still clinging on solidly should not be pulled out with soft brick buildings.

Cement pointing and waterproofing are not generally a good idea on old properties. Lime evaporates damp from a wall better than cement mortar. Waterproofers stop or reduce evaporation, thus making the wall wetter.


Foundations vary, some houses have none, 3 brick (13") foundations were quite common in the Vic period, as were 2' and other options. Foundations or lack of them is not normally a cause for concern.

Lime is much softer than cement. 1850s soft bricks are much softer than most cement & concrete.

Have you checked out the damp faq?


NT