The Arches

I have had an interesting week, a dry rot investigation in Kent followed by a damp assessment in South East London en-route back home.

The dry rot investigation was on a listed commercial building and the damp assessment was for a residential client, both interesting in their own rights. 

However, it was whilst assessing the causes for the damp defects on my clients mid-terrace property, that I caught a glimpse of an unusual feature in the brickwork.

The clients builder had removed a suspended timber floor due to a suspected infection of “dry rot”, leaving me standing on the solum, when I caught sight of a brick arch beneath the bitumen damp proof course. Upon closer inspection, a series of arches had been constructed on both the party wall and the opposite external wall.

My original desk study had not raised any issues with properties in the area but professional curiosity had got the better of me, so on Monday morning I made some phone calls. I called the local authority conservation and building control officers (Greenwich) to ask if they had come across anything similar. They were very helpful as always, but could not explain the purpose of the arches. 

My thoughts, for what it’s worth, are that the arches were designed to help any build up of groundwater flow between properties which had been built (1890 ish) on marsh/wet land.

Fortunately, this didn’t have a bearing on the damp investigation, those defects had been caused by a combination of inappropriate “improvements” and leaking water pipes.

I would like to hear from anyone who has any further understanding of these relieving arches.