New Phyisical Damp Course.

[volvomanx]

I live in a bungalow built with solid 9 inch walls and because of this, I have condensation problems. This is made worse though by a bit of rising damp in various places. [A previous owner took up the wooden suspended floors and filled with concrete, bridging the damp course in many places and encasing the central heating pipes]. I want to insulate and dry-line the walls but before I do I want to replace the physical damp course.
I know this is a trial but I prefer to do this than inject or cream. The trouble is, I have only found one site that explains the process but not in full detail.
I intend to use a concrete chainsaw to remove the old damp course, a metre a time, and use a good quality DPM then slate wedges and mortar to refill. Has anyone any thoughts?
I can't afford to get this done by a professional.
Thanks for reading,
volvomanx

 

[cumbriahandyman]

I live in a bungalow built with solid 9 inch walls and because of this, I have condensation problems. This is made worse though by a bit of rising damp in various places. [A previous owner took up the wooden suspended floors and filled with concrete, bridging the damp course in many places and encasing the central heating pipes]. I want to insulate and dry-line the walls but before I do I want to replace the physical damp course.
I know this is a trial but I prefer to do this than inject or cream. The trouble is, I have only found one site that explains the process but not in full detail.
I intend to use a concrete chainsaw to remove the old damp course, a metre a time, and use a good quality DPM then slate wedges and mortar to refill. Has anyone any thoughts?
I can't afford to get this done by a professional.
Thanks for reading,
volvomanx

Are you sure that you have rising damp? All of your problems could be down to condensation.

Any chance of a picture or three?

 

[volvomanx]

Thanks for the prompt reply mate.
I have taken 3 pics and I will try to send.[not very good at this]
I do have condensation probs as well, partial central heating and some loft insulation removed. I'm in the process of renewing both.
Regards,
volvomanx

 

[volvomanx]

http://media.diynot.http://media.diynot.com/130000_129130_32331_16788361_thumb.jpg com/130000_129130_32329_2187//media.diynot.com/130000_129130_32332_64764850_thumb.jpg7165_thumb.jpg

Sorry mate. I think you will get pics now.
Regards,
volvomanx

 

[cumbriahandyman]

'Damp' kitchen wall

'Damp' kitchen wall.

• volvomanx
• 21 Mar 2011
• 1

Damp wall/floor

Damp wall/floor

• volvomanx
• 21 Mar 2011
• 1

The lower black line is the pitch DPM. As you can see, the screed here caused a bridge.

The damp line rose to just under a metre but is now reducing in
height to approx 600mm over the past two weeks.

Damp wall.

• volvomanx
• 21 Mar 2011
• 1

The lower black line is the pitch DPM. As you can see, the screed here caused a bridge.<br>The...

 

[JohnD]

the pictures look to me like wet from the floor, not condensation. However moisture will evaporate from a wet floor and cause the house to be humid, which will lead to condensation.

It is a pity the floor is so wet. I imagine it was poured with no dpm, as it looks such a shoddy job. It would be very tiresome to break it up and dig it out, but might be worth a trial hole in case you are lucky, and the concrete is such poor quality, or so thin over rubble, that it is easy to dig out

Unfortunately concrete which is kept damp for a long period cures very thoroughly, and reaches a hight state of hardness and strength.

If he left plaster rubble or wood rubbish under the floor, it may bulge and crack or promote rot

 

[foxhole]

What ventilation do you have?

 

[volvomanx]

Hi foxhole,JohnD and cumbriahandyman,
Thanks for all your views and ideas.
Ventilation in the kitchen is down to draughty old ally double glazing, and in the bathroom, we have a broken ext fan, but have a dehumidifier permanently sited there. We are 5, so can be a steamy room. New extractor fans are destined for both areas.
My plan is to, 1. renew the damp course, 2. insulate the ext walls with up to 100mm.Celotex. I may remove plaster/render first and put Oldroyd Clear Cavity membrane against the brickwork before I insulate, but I would rather not have to install a drain for this. At the same time, 3. I want to remove the concrete floors and replace with block and beam. This will keep the floor away from the wall. With the floor removed, I want to take the membrane and insulation into the floor cavity, but re-establish the air vents but through the insulation, then block n beam. The Oldroyd membrane will enable the brickwork to vent into the loft and under the new floor which should keep the wall dry so no cavity drain. That's the theory anyway.
I have old central heating pipes and two iron gas pipes [live] encased in the flooring and I would prefer to remove them.
As you can see, this is a lot of work and I don't want to leave out the DPM replacement and get problems in 5 years time.
Regards,
volvomanx

 

[foxhole]

With no adequate ventilation the damp is almost certainly down to condensation.Kitchen requires a permanently open vent plus mechanical extraction when cooking.Do you dry washing indoors?

 

[volvomanx]

Hi foxhole,
We dry washing outside if poss but over the winter it is dried in the bathroom where the dehumidifier is always sited. Damp towels after showers are also dried in the bathroom.
I know we do have quite a serious condensation issue but along side this seems to be what appears to be rising damp???. The affected walls clearly show the wet demarkation line travelling up or down the wall. The problem seems to be worse in the kitchen and also in the bedroom diagonally opposite, so one room front right and the other room back left so to speak. Interestingly, the downpipe from both gutters enters the ground on the outside of both these walls and I need to make sure that the rainwater is piped away from the building and not just sitting under the ground. This is why I have said I intend to install a French Drain in any case.
As I have said, we do not have heating in all rooms at all times for the moment until I have completed the heating install.
Regards,
Volvomanx

 

[foxhole]

Condensation will produce the damp you have , dehumidifier will not cope with moisture content you are producing, no such thing as rising damp[moisture falls thru walls until base is saturated hence the low damp.].You need lots of ventilation to solve your problems.

 

[volvomanx]

Ok, thanks for your valid opinion foxhole.
Can you see a problem with me using the Oldroyd membrane against the brickwork before I insulate. As I said, this method will create airflow between the attic and sub floor with the air flowing behind the membrane, which is dimpled, and over the brickwork surface. I will use Celotex thermal break board, 25mm over the membrane, then Celotex general application to 75mm, then a membrane to the warm side of the insulation before plasterboarding. I'm not sure if either of the above boards are foil backed but I will look at this before I decide which to use. I intend to use extraction in the kitchen and bathroom.
Regards,
volvomanx

 

[cumbriahandyman]

Conensation...

Clicky Thing

 

[volvomanx]

Thanks for the Clicky Thing cumbraihandyman.

I guess with all the above views and advice I will forget about the rising damp theory and go with trying to alleviate the condensation.
Thanks everybody for your input.
Regards,
volvomanx