rising damp again

[Timmo]

would appreciate some views on my rising damp problem (I couldn't see anything similar to this on previous posts) but recognise some of the questions.

Old cottage, recently renovated within last 10years. concrete rendering on external walls with evidence of damp proof injection (2drill holes per brick) Solid walls.

i redrilled the holes and on internal and external and re injected the brick will the solution. the brick work was crumbling and the mortar was in a similar state, also the mortar course was excessive.

THe house has been empty for a year and damp marks are evident up to 1m high on the internal walls again.

however there is a gap between the floor and about 1 foot high where the walls do not have any marks.

I do not believe there is water coing from the outside at any point

any help would be appreciated

 

[brumylad]

concrete render often means water can get behind it through pores or cracks and the easiest way for it to get out again would be through the brickwork to the interior.

Some experts don't believe chemical DCP's don't work, especially in solid brick walls. Does the property have an original DPC ? usually slate or bitumen.

it could be condensation, as soon as the temperature of any part of the wall goes below the dew point, water will condense within the brick. With solid walls its important to heat the building.

 

[Timmo]

Brumylad

thanks for the reply, the exteria is concrete rendered, so I assume that this will not give me any advantage. the house has been empty since I injected the walls with chemical compound. although I was hoping that the summer months would help.

I cannot see any original protection although I suspect the extra ground level may be different.

I am now unsure if there is damp or I am looking at the stain caused by the previous marks. I guess the only solution would be a barrier of some sort, any recommendations?

Once again i appreciate the reply

 

[jbonding]

if you can imagine damp air and so on has to go somewhere, by the sounds of it theres evidence on the walls that the dampproofing is doing its job, vent the rooms and turn the heating on for a bit and see what happens. the damp will leave a stain that might look damp so stripping paper and removing old carpets you will notice a change if any.

 

[brumylad]

make sure the external ground level is at least 6 inches or 2 brick courses below the new damp proof course.

Like jbonding says, turn the heating on, could also hire a dehumidifier, waite a few weeks and see what happens.

 

[Timmo]

Brumylad / jbonding

Ill take your advice and turn the heating on see what happens. I also believe there is no fresh air into the room as it has been uninhabited for a year. thanks for the advice this could save me a big job.

cheers