Mysterious Damp

[cyqi]

I've been staying in my 1950s/1960s bungalow for more than 2 years. Damp starting to show around June this year (around the driest weather in history). It started around the one side wall of the house and one of the central supporting wall. Then wet patches on the wall start to appear, propagating from front of the house gradually to the back of the house. We had water company check the water main both in my house and my neighbours, but come up with no problem. They even check the fire Hydrant. I've also hired an independent surveyor to check, but he can not come with any conclusion. ok, here are the summary:
- Damp start june this year during dry period and getting progressively worse.
- The two bed room floor are very wet, my paquet floor are all wrapped and swelled up. Concrete floor
- Damp around skirting on one side of the walls.
- No leak from water main.
- Only interior wall is damp (cavity wall). The outer leaf is quite dry.
- Gutter is bit old, but in ok condition, should not lead to damp around the skirting.
- Roof ok, valley have been repointed to rule out leaking roof.
- Survey remove skirting and hacked some plaster off at the damp wall in the middle of the house, internal bricks is dry but plaster is wet.
- I'm not suspecting leak from the bathroom since all walls around the bathroom are not damp. (my surveyor is a bit sceptics about it). No pipe below bathroom floor, solid concrete
- All water pipe in the house including central heating either going along the roof or on the walls since we have concrete floor.
- No pressure drop in combi boiler. central heating piping are all exposed. No leak observed.
- No water and drainage pipe near the damp wall side, no pipeworks under floor.
- Condensation? Have lived in for two years, no such problem before. water appears far exceed what we produced. Walls and floors are soaking wet.
- No cavity insulation.

I'm desperate to find out where these water come from since we have a infant and mould start to appear in the bedrooms. With one surveyor and two civil engineering (both me and hubby although not really in building trade) failed to spot the reason, will appreciate if any one can point to a possible direction for further investigation!

[welsh brickie]

Could be failure of the damp proof membrane.Does the surrounding area slope towards the house? insufficent ground drainage could be a cause, an installation of a field drain may be nessasary.
Even in dry weather ground water will still seep into low lying areas.

[cyqi]

The damp proofing course has been checked by the surveyor and they are in good condition. The house is on flat plain, all surrounding area of similar level. if it is ground water problem surely i wont be the only one affected. my neighbour's wall is only 2m away.

[welsh brickie]

Im baffled,The only suggestion I can make is to take up the parquet flooring which is warped anyway,and paint the floor with buitumin paint to seal it.then relay the floor on wet buitumin.This will stop any damp through the floor.Install an airbrick in the room,this will stop condensation.Then spray the exterior wall with a silicone based solution like aquaseal,this will stop penitrating damp.