JAG

Thank you for your replies. To answer to Saveasteading - yes the DPC is where you have marked the red line although that is where everybody supposes it is. The source of the dampness is six inches either side of this corner with signs of damp carpet for about six feet inside the house along the left side of the photograph. I cut the trench about a month ago thinking it might reveal some holes but all seems OK - and it never has even damp patches. If you look at the moss growth it is light green when fairly dry, then dark green when wet - and as you will see in the photograph it is dark green for a couple of feet after only for two hours of light rain. The downpipe seems firmly cemented in so a major job to move - I ran a hose down in for twenty minutes without overflowing so I guess that system is clear. Your comments about shoddy trowel work is appreciated - the whole estate is similar and the building company went bust the day after handover leaving many problems which the residents were left to solve. Jilly it is guesswork quite where the soakaway is - probably under the pathway so difficult to know for certain although indications given above seem to suggest it is working OK.

This is the overall picture of the left corner. You can see how far the damp has crept in just a couple of hours in a morning. There is a DPC about two bricks up from ground.

This is the top of the corner. The right hand corner is identical and has no problems

Radian, the chain is simply a support for the clematis you can see at the base.

This is a photograph of the corner - for some reason printed twice. It was taken this morning after a couple of hours gentle rain and you can clearly see that the wetness of the green mold has already crept along. You can also see the DPC but the water ingress is above this. The downpipe goes to a soakaway but this is clear - and the chain is just decoration. To the left you will see a channel I cut in the paving in the hope of finding an open hole but no luck.

Thank you for your prompt replies. The property is part of an estate in Bedfordshire, flat chalky ground, slightly at the top of a hill but nothing exceptional. I bought it new about 40 years ago but do not know if it has cavity insulation. The wetness is worse in winter suggesting it is rain - but it is always there. The soffits and tiles are all in place. The wetness occurs in one outer corner of a bedroom, and the outside wall shows signs of moss growth below DPC. The wetness appears mainly as small trickles from behind the skirting and mainly above the DPC. The problem has been developing for probably four or five years, firstly as a mild damp patch but now more serious, and there has not been any building modernisation in that area of the property for a decade. My thinking is that rainwater is leaking into and settling in the cavity but I cannot find from where - everything seems OK. I have drilled a number of weep holes but nothing shows. Water services are all on the far side of the building. I am confused and want to find a professional - but who ??

A 1970's bungalow. We have rainwater ingress above dampcourse level to the extent that the room is becoming uninhabitable. To the average DIYer there are no obvious entry points where the water can enter. I want to get a professional in to deal with the problem but who do I contact. It seems to be beyond any local builder - and it seems outside the scope of companies dealing with condensation.