rising damp in the corner.

[jeds]

hmmm.... ok, i might be wrong, im not so sure now.

ive drilled into the infected area and the wall appears dry under the surface, thats one thing ive learned off those vids...

but it still begs the question that if rising damp is a myth, why has nobody noticed injection doesnt work?

It's widely known that damp injection is a waste of time and money. Any decent building surveyor knows that. The problem is the average valuation surveyor doesn't. I've had this conversation with many valuation surveyors over the years and the unashamed answer they always give is that it is outside their technical range. They see what looks like damp so they report it and leave it to somebody else to deal with the cause and treatment. That then goes to a nobody in a lenders office who says the damp must be treated - that then goes to a damp surveyor who, lo and behold, says it needs a damp proof injection. Another three grand in the bank thank you very much.

What really happens is the additional works that go along with injection can often partially solve the problem - in the medium or short term anyway. Hacking off and replastering removes salts contamination or alters the environmental balance. Or waterproof sand cement render holds back penetrating damp for a while. A bloke once told me that he won't inject anything unless the client agrees to have surface insulation in the making good. I asked him if that was because he knew it was the insulation solving the problem not the injection - he just smiled.

 

[Johnmelad]

but it still begs the question that if rising damp is a myth, why has nobody noticed injection doesnt work?

They of course have, but when it fails, you will be told that it is now condensation.

 

[Flyboytim]

What is the compass orientation of the affected corner?
Is the corner sheltered or exposed?
Is the wall solid (how thick from outside to inside finish) or cavity (what size cavity)?
Cavity moisture bridge check carried out?
Any cavity insulation (what type)?
Rendering or cladding to outside wall. Painted or bare surfaces outside?
How far is the DPC above the outside ground surface?
What type(s) of DPC, and when installed?
How close to internal floor level is DPC? DPM beneath quarry tiles? Underfloor heating?
Standard Brick or Brick and Cinder block construction (wall plugs not easy to fix because drill wanders once through the wall finish, dark grey or black dust) inside?
Is the wall plastered (lime? or gypsum?), dry lined with gypsum skim, or rendered with a cement mortar?
Is the wall finish uniform around the kitchen, or is the corner patched differently to the adjacent wall surface?
Skirting boards or finished to floor level?
Is the damp area normally behind units or furniture?
What is the decorative finish (if any) of the affected area?
Has any attempt been made to expose the brickwork behind the damp area to determine if the structure also is damp? (should have been exposed to apply Dryzone in a mortar course - was Dryzone applied at the recommended depths and intervals?)
Is the original construction mortar lime/sand or sand/cement? Pointing outside same as mortar or cement/sand on lime mortar courses?
Is there any water pipework in the wall or floor in the vicinity?
Has there been a flood (like washing machine overflow or other cause) in the past year?
Is there a "Tide Mark" of a different colour at the boundary edge of the damp area?
Is there a salt concentration band below the boundary edge of the damp area (conductivity meter readings)? Any efflorescence?
Have damp readings been taken of the wall from floor level at 200mm intervals to at least 500mm above the damp area, and to either side of the apparently damp area?

There is no way to tell if the damp is rising, penetrating or condensation just by observation. If there has been rising damp that has been cured in the past, without replastering the wall in the same type of plaster as the original finish, there may be continuing condensation problems.

Here's Dryzone's own comprehensive leaflet to check yourself:

http://static.dryzone.eu/sites/dryzone/theme/pdfs/datasheets/rising-damp-en.pdf[/QUOTE]

northeast
exposed
solid 2 brick depth
no cavity
no cwi
rendering on one side above the damp course
6"
1928, double row of blue bricks, assume nothing else.
below quarry tiles, floor raised above path. no idea whats under the quarry tiles
no underfloor heating
standard red brick
removed plaster, it was wet, bare brick now, even around the room
no skirting
no units, been exposed for 2 years, refuses to dry out but less wet in dry summer.
exposed
measured recomended intervals, but the drill might not have been long enough.
think its sand/cement (assumed so, dont know what lime/mortar looks like, assume its for thatched/old buildings)
pipes are a metre away, walls dry behind pipes, no pipes by affected area
no flood
yes to tide mark,
yes to salts
no damp readings, the bricks are damp and mouldy, others are dry and clean.

cant be penetrating, that comes via a fault in the drainage system/waterproofing the house. cant be condensation as its to local and nowhere else has it. pictures online strongly suggest it is rising damp, plus when its dry outside there often a damp patch on the concrete path, matching a smaller one inside on the quarry tiles.

thanks for your detailed reply, appreciated.

Thanks for answering.

A north east exposed corner with solid red brick wall with no insulation, rendered above damp course - on one side (northern side by any chance?), not the other - DPC of 2 courses of Blue bricks, probably a porous lime mortar from 1928 because that's what was commonly in use then, not the more expensive Portland cement and washed soft sand variety. Damp course working as originally intended, not compromised by high ground levels nor guttering insufficiency etc.

The rendering is probably not allowing the bricks to breathe and dry out during the seasons, trapping moisture in the wall above the damp course. On the other side (Eastern?) the bricks in the corner are cold even in summer, because they are evaporating moisture from the rendered wall. Very little sunlight ever warms that corner.

That corner is obviously going to stay cold, and even in summer, attractjng moisture inside by condensation.

But it has had rising damp in the past, treated by injection. The "rising damp" possibly originates under the quarry tiles, where the best of DPMs in the 1920s were a bed of bitumen over a concrete screed base which was possibly brick rubble or clinker from furnaces and lime based binder. The acidic or alkaline clinker, brick rubble and lime may have attracted moisture from the subsurface, and remained wet, feeding salts into the inner skin of the wall above the DPC. But the quarry tiles were never designed to be dry, they were designed to be cleaned by mop!

In the 1920 s & 30s people burnt coal in the kitchen, to feed the stove, hot water boiler and the wash boiler. How many flues do you think once came out of that kitchen? The kitchen was often the warmest room of the house, with a sink and table and a few chairs, and maybe a dresser, but little else With the stove always hot . People had the tin bath in there on Saturday or Sunday for the family to use in succession. and there were draughts from under doors and through windows which went up the chimneys. The tiled floor was scrubbed and mopped daily with washing soda and dried with rags. It would not have been possible to ask "had the kitchen been flooded in the last 6 months" in those days.

In the 1950s & 60s people started to change the kitchen to gas and electric for water, heating, cooking and washing, laid vinyl floor coverings and fitted kitchen cupboards to walls, and in the subsequent years, replaced draughty wooden sashes and metal windows with sealed double glazing, and put a radiator from the central heating in some unused area of wall in the kitchen, and reinstated the original tiles, especially once the laminate flooring had warped after a couple of years.

The 30-odd years of soda penetrating into the walls, the cold spot in the corner, the NE exposed orientation and rendering without insulation and undoubted condensation from normal living activities have led to the situation described here.

What can be done - dry lining is one possibility, with insulation between the plasterboard and wall. make sure the plasterboard does not meet the floor, and some form of skirting like UPVC can be used to cover the gap. I see no point in lifting the tiles, but if you ever consider tiling over, make underfloor heating a priority.

I doubt if the rendering will be easily or neatly removed on the outside wall, but application of a water shedding agent like Thompsons to the outer brick wall may help to remain dry and warm it over time. Making air circulate indoors with low noise low wattage oscillating fans can help turn a damp cold corner into one that is the same temperature as the internal air, and thus no condensation will be possible, and the corner will dry and warm up when it does. Extract steam from cooking and washing, open windows on dry days, but don't bother if the weather is cold and damp, and do not intermittently heat rooms during the day, rather keep them at a constantly low warmth.

Before turning on the fan, paint neat thick bleach on the mouldy/ salty areas of brickwork, do not scrub., do not wash the bleach off, and allow to soak in & dry with the fan on. You may need to repeat on occasion. This will help to replace alkaline carbonate salts with Sodium chloride, which is neither highly deliquescent nor efflorescent, as well as killing mould spores and hyphae, and removing their stains.

 

[robshaw42]

What is the compass orientation of the affected corner?
Is the corner sheltered or exposed?
Is the wall solid (how thick from outside to inside finish) or cavity (what size cavity)?
Cavity moisture bridge check carried out?
Any cavity insulation (what type)?
Rendering or cladding to outside wall. Painted or bare surfaces outside?
How far is the DPC above the outside ground surface?
What type(s) of DPC, and when installed?
How close to internal floor level is DPC? DPM beneath quarry tiles? Underfloor heating?
Standard Brick or Brick and Cinder block construction (wall plugs not easy to fix because drill wanders once through the wall finish, dark grey or black dust) inside?
Is the wall plastered (lime? or gypsum?), dry lined with gypsum skim, or rendered with a cement mortar?
Is the wall finish uniform around the kitchen, or is the corner patched differently to the adjacent wall surface?
Skirting boards or finished to floor level?
Is the damp area normally behind units or furniture?
What is the decorative finish (if any) of the affected area?
Has any attempt been made to expose the brickwork behind the damp area to determine if the structure also is damp? (should have been exposed to apply Dryzone in a mortar course - was Dryzone applied at the recommended depths and intervals?)
Is the original construction mortar lime/sand or sand/cement? Pointing outside same as mortar or cement/sand on lime mortar courses?
Is there any water pipework in the wall or floor in the vicinity?
Has there been a flood (like washing machine overflow or other cause) in the past year?
Is there a "Tide Mark" of a different colour at the boundary edge of the damp area?
Is there a salt concentration band below the boundary edge of the damp area (conductivity meter readings)? Any efflorescence?
Have damp readings been taken of the wall from floor level at 200mm intervals to at least 500mm above the damp area, and to either side of the apparently damp area?

There is no way to tell if the damp is rising, penetrating or condensation just by observation. If there has been rising damp that has been cured in the past, without replastering the wall in the same type of plaster as the original finish, there may be continuing condensation problems.

Here's Dryzone's own comprehensive leaflet to check yourself:

http://static.dryzone.eu/sites/dryzone/theme/pdfs/datasheets/rising-damp-en.pdf[/QUOTE]

northeast
exposed
solid 2 brick depth
no cavity
no cwi
rendering on one side above the damp course
6"
1928, double row of blue bricks, assume nothing else.
below quarry tiles, floor raised above path. no idea whats under the quarry tiles
no underfloor heating
standard red brick
removed plaster, it was wet, bare brick now, even around the room
no skirting
no units, been exposed for 2 years, refuses to dry out but less wet in dry summer.
exposed
measured recomended intervals, but the drill might not have been long enough.
think its sand/cement (assumed so, dont know what lime/mortar looks like, assume its for thatched/old buildings)
pipes are a metre away, walls dry behind pipes, no pipes by affected area
no flood
yes to tide mark,
yes to salts
no damp readings, the bricks are damp and mouldy, others are dry and clean.

cant be penetrating, that comes via a fault in the drainage system/waterproofing the house. cant be condensation as its to local and nowhere else has it. pictures online strongly suggest it is rising damp, plus when its dry outside there often a damp patch on the concrete path, matching a smaller one inside on the quarry tiles.

thanks for your detailed reply, appreciated.

Thanks for answering.

A north east exposed corner with solid red brick wall with no insulation, rendered above damp course - on one side (northern side by any chance?), not the other - DPC of 2 courses of Blue bricks, probably a porous lime mortar from 1928 because that's what was commonly in use then, not the more expensive Portland cement and washed soft sand variety. Damp course working as originally intended, not compromised by high ground levels nor guttering insufficiency etc.

The rendering is probably not allowing the bricks to breathe and dry out during the seasons, trapping moisture in the wall above the damp course. On the other side (Eastern?) the bricks in the corner are cold even in summer, because they are evaporating moisture from the rendered wall. Very little sunlight ever warms that corner.

That corner is obviously going to stay cold, and even in summer, attractjng moisture inside by condensation.

But it has had rising damp in the past, treated by injection. The "rising damp" possibly originates under the quarry tiles, where the best of DPMs in the 1920s were a bed of bitumen over a concrete screed base which was possibly brick rubble or clinker from furnaces and lime based binder. The acidic or alkaline clinker, brick rubble and lime may have attracted moisture from the subsurface, and remained wet, feeding salts into the inner skin of the wall above the DPC. But the quarry tiles were never designed to be dry, they were designed to be cleaned by mop!

In the 1920 s & 30s people burnt coal in the kitchen, to feed the stove, hot water boiler and the wash boiler. How many flues do you think once came out of that kitchen? The kitchen was often the warmest room of the house, with a sink and table and a few chairs, and maybe a dresser, but little else With the stove always hot . People had the tin bath in there on Saturday or Sunday for the family to use in succession. and there were draughts from under doors and through windows which went up the chimneys. The tiled floor was scrubbed and mopped daily with washing soda and dried with rags. It would not have been possible to ask "had the kitchen been flooded in the last 6 months" in those days.

In the 1950s & 60s people started to change the kitchen to gas and electric for water, heating, cooking and washing, laid vinyl floor coverings and fitted kitchen cupboards to walls, and in the subsequent years, replaced draughty wooden sashes and metal windows with sealed double glazing, and put a radiator from the central heating in some unused area of wall in the kitchen, and reinstated the original tiles, especially once the laminate flooring had warped after a couple of years.

The 30-odd years of soda penetrating into the walls, the cold spot in the corner, the NE exposed orientation and rendering without insulation and undoubted condensation from normal living activities have led to the situation described here.

What can be done - dry lining is one possibility, with insulation between the plasterboard and wall. make sure the plasterboard does not meet the floor, and some form of skirting like UPVC can be used to cover the gap. I see no point in lifting the tiles, but if you ever consider tiling over, make underfloor heating a priority.

I doubt if the rendering will be easily or neatly removed on the outside wall, but application of a water shedding agent like Thompsons to the outer brick wall may help to remain dry and warm it over time. Making air circulate indoors with low noise low wattage oscillating fans can help turn a damp cold corner into one that is the same temperature as the internal air, and thus no condensation will be possible, and the corner will dry and warm up when it does. Extract steam from cooking and washing, open windows on dry days, but don't bother if the weather is cold and damp, and do not intermittently heat rooms during the day, rather keep them at a constantly low warmth.

Before turning on the fan, paint neat thick bleach on the mouldy/ salty areas of brickwork, do not scrub., do not wash the bleach off, and allow to soak in & dry with the fan on. You may need to repeat on occasion. This will help to replace alkaline carbonate salts with Sodium chloride, which is neither highly deliquescent nor efflorescent, as well as killing mould spores and hyphae, and removing their stains.

appreciate this comprehensive reply. yep there was a fireplace, ill act upon your suggestions...ive dry lined the rest of the house with plasterboard with insulation on all the outer walls. i didnt do this one because it was too wet!

thanks again.