Dry lining a damp wall

Discussion in 'Misc DIY' started by Bodgit, Dec 28, 2006.

  1. Bodgit

    Bodgit Guest

    The problem (sorry it's a bit long):

    Moved into our 150 year old house (soft brick and no DPC) a year and a
    half ago. I knew there were some damp issues and I've addressed some in
    other parts of the house, but we've just stripped the wallpaper off one
    room and the problems are a lot more severe than I thought.

    The house is on a hill and this room is "underground" - there is no
    earth touching the walls as there are retaining walls outside with a
    gap between those and the house.

    The room has always felt damp (black mould etc.) but I originally
    thought the problems were due to condensation. I've now pretty well
    ruled that out though. The whole house is well heated and there are few
    sources of water vapour.

    The room has 2 external and 2 internal walls:
    - external wall 1: has no windows. Plaster has blown over full length
    up to a height of about 2 ft. No evidence of injected DPC but plaster
    has been replaced on lower half of wall previously.
    - external wall 2: contains 1 window. Wall in fairly good condition.
    Evidence outside of injected DPC. No evidence that plaster has been
    replaced.
    - internal wall 1: plaster blown over full length up to height of
    about 1ft. Plaster on lower half of wall has been replaced previously.
    Opposite side of wall has been drylined.
    - internal wall 2: has radiator. According to previous owner this has
    had DPC injected and plaster replaced about 5 years ago. Plaster coming
    away either side of radiator. Opposite side of wall is a fully tiled
    bathroom (rarely used). The only pipes in or on this wall are radiator
    pipes which are fully visible and not leaking.

    The floor doesn't seem to be damp (carpeted). The skirting is made from
    quarry tiles. This area used to be the cellar of a large manor house.
    The ceiling (and floor of room above) is made from 14" thick reinforced
    concrete.

    Where the plaster has blown the brick feels quite damp. The plaster
    that has not blown doesn't feel particularly damp. There are no pipes
    etc. except for the radiator. The rainwater goods are in good order.
    The floor level outside is about the same as the floor level inside,
    made from concrete and drains away from the house. I'm convinced this
    is rising damp.

    The solution:

    I know all the stuff about old properties - that you should allow the
    walls to breathe and and have lots of ventilation etc. but I can't
    really see that being practical!

    This room has obviously been a problem for some time and has had many
    attempts to solve the damp issues.

    I'm wondering whether the best course of action would be to dryline the
    whole thing. I would imagine I would need to use some sort of vapour
    barrier and treated batons. Does anyone have any idea how long this
    arrangement would last?

    Any other ideas? I've seen membrane systems that you bury under the
    floor and run right up to the ceiling before plastering over, but as
    the floor is not damp I don't think this is necessary.

    Any more suggestions would be very welcome!
     
    Bodgit, Dec 28, 2006
    #1
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  2. Bodgit

    Guest

    Bodgit wrote:

    > The problem (sorry it's a bit long):
    >
    > Moved into our 150 year old house (soft brick and no DPC) a year and a
    > half ago. I knew there were some damp issues and I've addressed some in
    > other parts of the house, but we've just stripped the wallpaper off one
    > room and the problems are a lot more severe than I thought.
    >
    > The house is on a hill and this room is "underground" - there is no
    > earth touching the walls as there are retaining walls outside with a
    > gap between those and the house.
    >
    > The room has always felt damp (black mould etc.) but I originally
    > thought the problems were due to condensation. I've now pretty well
    > ruled that out though. The whole house is well heated and there are few
    > sources of water vapour.
    >
    > The room has 2 external and 2 internal walls:
    > - external wall 1: has no windows. Plaster has blown over full length
    > up to a height of about 2 ft. No evidence of injected DPC but plaster
    > has been replaced on lower half of wall previously.
    > - external wall 2: contains 1 window. Wall in fairly good condition.
    > Evidence outside of injected DPC. No evidence that plaster has been
    > replaced.
    > - internal wall 1: plaster blown over full length up to height of
    > about 1ft. Plaster on lower half of wall has been replaced previously.
    > Opposite side of wall has been drylined.
    > - internal wall 2: has radiator. According to previous owner this has
    > had DPC injected and plaster replaced about 5 years ago. Plaster coming
    > away either side of radiator. Opposite side of wall is a fully tiled
    > bathroom (rarely used). The only pipes in or on this wall are radiator
    > pipes which are fully visible and not leaking.
    >
    > The floor doesn't seem to be damp (carpeted). The skirting is made from
    > quarry tiles. This area used to be the cellar of a large manor house.
    > The ceiling (and floor of room above) is made from 14" thick reinforced
    > concrete.
    >
    > Where the plaster has blown the brick feels quite damp. The plaster
    > that has not blown doesn't feel particularly damp. There are no pipes
    > etc. except for the radiator. The rainwater goods are in good order.
    > The floor level outside is about the same as the floor level inside,
    > made from concrete and drains away from the house. I'm convinced this
    > is rising damp.
    >
    > The solution:
    >
    > I know all the stuff about old properties - that you should allow the
    > walls to breathe and and have lots of ventilation etc. but I can't
    > really see that being practical!
    >
    > This room has obviously been a problem for some time and has had many
    > attempts to solve the damp issues.
    >
    > I'm wondering whether the best course of action would be to dryline the
    > whole thing. I would imagine I would need to use some sort of vapour
    > barrier and treated batons. Does anyone have any idea how long this
    > arrangement would last?
    >
    > Any other ideas? I've seen membrane systems that you bury under the
    > floor and run right up to the ceiling before plastering over, but as
    > the floor is not damp I don't think this is necessary.
    >
    > Any more suggestions would be very welcome!


    To understand why its damp and how to solve it, ask on
    http://periodpropertyshop.co.uk/phpBB2/viewforum.php?f=1
    and read the damp faq first.


    NT
     
    , Dec 28, 2006
    #2
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  3. Bodgit

    Bodgit Guest


    > To understand why its damp and how to solve it, ask on
    > http://periodpropertyshop.co.uk/phpBB2/viewforum.php?f=1
    > and read the damp faq first.


    I've read the FAQ. I'm pretty sure I understand why it's damp.

    Our house is a wing of an old manor house. In the 1850s this area of
    the house (17' square) was a coal cellar. The room next door (20' x
    17') was a boiler room. The kitchen (20' x 17') was above. When it was
    built it probably didn't matter that it was damp - the coal-fired
    boilers, kitchen and open windows would have kept things pretty well
    under control. And if the coal cellar was a bit damp who cares? It was
    never designed to be lived in. But that's what we're trying to do.

    I'm aware of your oppinion that rising damp doesn't exist. But in this
    case I think that's exactly what it is (yes - quite possibly brought
    about by the concrete floors that were laid in the seventies).

    If I were to ask on PP, I'd be told to rip off all the plaster,
    re-plaster with lime plaster, take up the concrete floors and get some
    reed matting instead of carpets. I don't want to do this - I want a
    practical solution. I know that we've 'asked for it' by messing around
    with the natural breathability of the house. And I know that any
    solution would probably not last forever. I just want to make the room
    livable.
     
    Bodgit, Dec 28, 2006
    #3
  4. Bodgit

    Guest

    Bodgit wrote:

    > > To understand why its damp and how to solve it, ask on
    > > http://periodpropertyshop.co.uk/phpBB2/viewforum.php?f=1
    > > and read the damp faq first.


    > I've read the FAQ. I'm pretty sure I understand why it's damp.
    >
    > Our house is a wing of an old manor house. In the 1850s this area of
    > the house (17' square) was a coal cellar. The room next door (20' x
    > 17') was a boiler room. The kitchen (20' x 17') was above. When it was
    > built it probably didn't matter that it was damp - the coal-fired
    > boilers, kitchen and open windows would have kept things pretty well
    > under control. And if the coal cellar was a bit damp who cares? It was
    > never designed to be lived in. But that's what we're trying to do.
    >
    > I'm aware of your oppinion that rising damp doesn't exist.


    Thats not my opinion.

    > But in this
    > case I think that's exactly what it is (yes - quite possibly brought
    > about by the concrete floors that were laid in the seventies).
    >
    > If I were to ask on PP, I'd be told to rip off all the plaster,
    > re-plaster with lime plaster, take up the concrete floors and get some
    > reed matting instead of carpets. I don't want to do this - I want a
    > practical solution.


    I think youre jumping to conlcusions before theyre due there, you
    really dont know until you ask. The solutions I've seen on ppuk tend to
    be a good deal more practical than other approaches offered IME.


    > I know that we've 'asked for it' by messing around
    > with the natural breathability of the house. And I know that any
    > solution would probably not last forever.


    why not?

    > I just want to make the room
    > livable.


    I think your assumptions may be getting in the way.


    NT
     
    , Dec 29, 2006
    #4
  5. In article <>,
    "Bodgit" <> writes:
    > The problem (sorry it's a bit long):
    >
    > Moved into our 150 year old house (soft brick and no DPC) a year and a
    > half ago. I knew there were some damp issues and I've addressed some in
    > other parts of the house, but we've just stripped the wallpaper off one
    > room and the problems are a lot more severe than I thought.
    >
    > The house is on a hill and this room is "underground" - there is no
    > earth touching the walls as there are retaining walls outside with a
    > gap between those and the house.


    Can you inspect it? Is the gap clear of any debris?
    Is is running with water?

    > The room has always felt damp (black mould etc.) but I originally
    > thought the problems were due to condensation. I've now pretty well
    > ruled that out though. The whole house is well heated and there are few
    > sources of water vapour.


    That alone doesn't rule it out.
    For example, if those walls are remaining colder than the air
    temperature, they could be forming condensation. Have you checked
    the temperature of the walls where they are damp (need an Infra-red
    thermometer for this). Given the air temperature and humidity, it
    is possible to look up the dew point (temperature below which the
    wall will form condensation).
    See: http://www.tis-gdv.de/tis_e/misc/klima.htm
    For example, a room at 20C air temperature and 50% humidity will
    cause condensation on a wall at a temperature of 12C or lower.

    > The room has 2 external and 2 internal walls:
    > - external wall 1: has no windows. Plaster has blown over full length


    Blown plaster is not necessarily a sign of damp. It could have
    been blown a week after being plastered, due to poor plastering.

    --
    Andrew Gabriel
     
    Andrew Gabriel, Dec 29, 2006
    #5
  6. Bodgit

    Bodgit Guest

    > Can you inspect it? Is the gap clear of any debris?
    > Is is running with water?


    Yes - the retaining walls are about 4ft from the house walls so it's
    easy to walk around. The space between the two is filled with concrete
    which is about at the internal floor level and slopes away from the
    house into an open channel that runs along the bottom of the retaining
    wall. The only damp area outside is at the bottom of the retaining wall
    - the channel gets a bit full of leaves sometimes and water can sit
    there, but it's not against the house.

    > That alone doesn't rule it out.
    > For example, if those walls are remaining colder than the air
    > temperature, they could be forming condensation. Have you checked
    > the temperature of the walls where they are damp (need an Infra-red
    > thermometer for this). Given the air temperature and humidity, it
    > is possible to look up the dew point (temperature below which the
    > wall will form condensation).
    > See: http://www.tis-gdv.de/tis_e/misc/klima.htm
    > For example, a room at 20C air temperature and 50% humidity will
    > cause condensation on a wall at a temperature of 12C or lower.


    Thanks for the info. I'll do that when I get home in a few days' time.
    I can accept that the external walls may suffer from condensation - the
    dadmage may well have been done before we moved in. But the internal
    walls must all be at around the same temperature, so I would have
    thought that if one wall suffered then they all would. I'll check with
    the IR thermometer and get back to you.

    > Blown plaster is not necessarily a sign of damp. It could have
    > been blown a week after being plastered, due to poor plastering.


    The wall feels wet though! I'm quite prepared to drill a hole in the
    wall to see whether the wetness is on the surface or penetrating right
    through. Anyone care to suggest a technique for doing this?
     
    Bodgit, Dec 30, 2006
    #6
  7. Bodgit

    Bodgit Guest

    > In that case maybe all the walls should be injected. Better to do that
    > yourself to ensure the right amount of fluid is used (I don't trust
    > contractors). Damp on the lower part of an internal wall strongly
    > suggests that it's rising, and this would be a low cost first step.


    I'm prepared to give it a go. Can you suggest a good product? I've
    looked at Dryzone, which looks fairly easy - is it possible to hire the
    injection gun or should I just buy one?

    > Wooden battens wouldn't last long on the wet side of the barrier.


    Even if they were tanalised?

    > I suppose you could use plastic and stainless steel fixings, but I
    > wouldn't embark on anything that drastic before trying other options.
    > You'd be losing space and would have to line up the new surface with
    > windows and doors somehow.


    I don't mind losing a couple of inches or so as it's a fairly big room
    anyway. I can work around the door and window without too much fuss.

    > I know of one property round here where foil faced plasterboard was
    > slapped directly on to damp brickwork during "renovation". The internal
    > walls still look good 5-6 years later, so I guess they got away with it.


    Would you agree that if it *IS* condensation then drylining would
    probably improve matters. If it's rising damp then the injected DPC
    would would offer the best bet, and drylining as well won't hurt.
     
    Bodgit, Dec 30, 2006
    #7
  8. Bodgit

    Bodgit Guest

    > Dry lining cellar walls with plasterboard, that has a concrete floor and
    > ceiling just will not work.
    > You will get condensation forming behind the plasterboard with no escape
    > route


    Would a plastic membrane directly behind the plasterboard not be a
    solution?

    > Tanking is really the only sensible option in this situation if you want to
    > use it as a modern habitable room.
    > a limewash loony will be along shortly to advise digging a French ditch and
    > letting the walls breath.


    We don't have a problem with the floor - just the walls. It might sound
    stupid but Is it possible to to just tank the walls?
     
    Bodgit, Dec 30, 2006
    #8
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