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Housing - Renovation: Damp... can anyone help

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  1.  
    • CommentAuthorDaniel B
    • CommentTimeAug 6th 2007
     
    I recently took on a renovation project and there are some damp patches on the internal walls. Discolouring is visible in several places and I think it may be rising damp? I'm nervous about getting quotes to repar the problem as I'm told they tend to dramatically over do it! Can anyone suggest a cheap, reliable DIY option?
    • CommentAuthortony
    • CommentTimeAug 6th 2007
     
    Don't let a damp company anywhere near it. It is NOT rising damp. Drill a hole and catch the dust, weigh it, put it in the airing cupboard for a few days and re weigh it = % moisture.

    Look for leaking gutters drips showers nearby, any other source of water condensation

    Where is this damp?
  3.  
    I'd agree with Tony - don't panic. We had damp in our first house and one of the reps from a damp company said "Did the previous houseowners use the room? Was there a large piece of furniture in the corner?" No they didn't appear to use the room and yes there'd been a large dresser/cupboard unit there. Well put the gas fire on low, keep the window open whenever you can and keep your furniture out of the corner was the answer. Problem solved . . . . it was internal condensation.
    Check all other sources of water ingress - gutters & downpipes (small cracks in cast iron ones will need you out there in the rain up a ladder), bathroom on floor above? What state is the pointing in? Is the building supposed to have a damp course? How high is the outside ground level in relation to DPC. Our house didn't have a DPC and didn't need one despite the fashion for the chemical injection type and hacking off 1m of internal plaster at the time.
    Do you have a cellar? Get all openings open (if you can) and install more airbricks if you can't feel any air moving through the cellar or underfloor crawl spaces. It's not really rocket science or expensive, just takes a little graft. Good luck!
  4.  
    'Condensation' just wouldn't have the same ring as the title for a TV show.
  5.  
    I've had the same thing on a couple of my internal walls downstairs. I wouldn't worry about it. I just stripped the paper, knocked off any loose plaster, patched it up with one-coat plaster, let it dry out properly, repapered and painted. Had a few light brown marks come through after a few months but gave it a coat of stain blocking paint and repainted over that and it hasn't come back.

    Had damp firm in my house because the bank insisted. Told me to rip up the quarry tiles and the timber floors, lay a concrete floor, knock all plaster off to metre and inject a damp proof course. I ignored him and 5 years later house has just passed a mortgage survey so shows what these people know.
  6.  
    A lot of 'damp' is certainly condensation, often self-inflicted by occupiers pushing large quantities of water vapour into the air eg drying clothes over ch rads, using portable gas heaters or unventilated gas cookers etc.

    In addition to comments made by others, three other items to consider.

    Chimneys are a frequent source when not in use. Either descending damp from rain penetration (I've known that reach about 15ft from the top of the stack down to bedroom floor level!) or condensation within disused chimneys which have been capped but not vented. They need a small air vent top and bottom.

    If there are gas appliances without a stainless steel chimney liner in an old chimney, , then again you will get serious condensation in the chimney flue which will produce large damp patches.

    Finally, some old plaster-type materials can be hygroscopic and actually soakup water from the atmosphere. All you can do is hack off and re-plaster.

    Rising damp is usually confined to the bottom couple of feet in the downstairs rooms. Lots of standard methods to combat. Very often the 'damp treatment' mobs are a con, in the sense that very often the problem is solved by other simultaneous renovations/heating/lifestyle changes and not by their expensive quack cures.
    • CommentAuthortony
    • CommentTimeAug 7th 2007
     
    Or just that the regularly specify waterproof re plastering to 1m up the wall. This has several effects; 1 no damp can get through it, 2 the wall often becomes very wet behind this waterproof render, 3 they never get called back cos even if they forgot to inject the wall would not show damp ( except condensation) 4 their actions are negative apart from their positive cash flow. 5 sometimes they drill so many holes that structural damage is being caused! eg properties that have had 4 or 5 injected damp courses insisted upon by mad building society surveyors. 6 When will this nonsense cease?

    Well done fun for ignoring them. I do too. Shall we form a club?
  8.  
    You're smack on with tha tony, I used to work for a dpc company when I first started plastering. Boss used to insist on 3:1 sand/Cement and lots of waterproof additives
    • CommentAuthortony
    • CommentTimeAug 8th 2007
     
    How do damp companies get away with re plastering and not attending to improving the thermal performance of the walls while they are about it?

    Do they ignore the rules or are they a special case? or ignorant? or does anyone even care?
  10.  
    There are are several loopholes and exclusions, have you got the Green Buiding Bible Vol 1? see pg153
  11.  
    Er, the house didn't quite pass the survey actually. The buyer's surveyor found "damp" in two internal walls although there is no visual evidence of any problem and no deterioration over the last 5 years since I decorated. Buyer "isn't worried" but has called a damp proofing firm in. By coincidence, it is the same firm whose advice I ignored 5 years ago! He should be able to find the place at least...

    Will be interesting to see what they recommend this time.
    • CommentAuthortony
    • CommentTimeAug 9th 2007
     
    I suspect that the "damp meter" used measured electrical conductivity. This is not the same as damp. Drill a hole catch the dust and weigh it, dry it reweigh etc.
    •  
      CommentAuthorNovy Mlyn
    • CommentTimeAug 13th 2007
     
    Daniel B, some really easy DIY: make sure that the ridge that runs on the underside of any window sill is free of gunk, sometimes this will stop the water dripping off before it reaches the wall. And the same thing with any air bricks, these are often blocked up in older houses.
    • CommentAuthorDaniel B
    • CommentTimeAug 13th 2007
     
    Thanks so much to everyone who wrote a reply, I feel loads better about it now. The damp is in the following areas: Chimney breast (mostly at the bottom - chimney capped but not vented, thanks 'funcrusher' - but also some nearer the middle) to the left and right of the stack there is some and on the internal walls in the dining room ad hall near ground level. These areas back onto the chimney breast so hopefully if I sort that they may all go away. There is some on the internal wall between me and next door (semi detached) which is slightly more worrying. Is the best plan:
    Vent chimney
    Check damp proof not breached (was when I bought the house but not apparently so now)
    Re plaster effected areas? Damp proof paint?
    • CommentAuthorbayouboy
    • CommentTimeAug 16th 2007
     
    I don't think anyone mentioned removing the moisture from the main sources : cooker and bathroom. Put in extractor ( not recirculating) fans and use them!
    • CommentAuthortony
    • CommentTimeAug 16th 2007
     
    Daniel -- yes ventilate the chimney -- party wall what is on the other side/ above? any bathrooms, showers? leeks?
    • CommentAuthordavid
    • CommentTimeAug 19th 2007
     
    If there are damp patches on your walls behind furniture and beads of moisture on the quarry tiled floor, it's almost certainly condensation .The warm air in the house contains moisture which condenses on any surface which is cooler and not porous.
    When I was a child most people lived in houses which were damp and had condensation problems. The houses were ventilated by draughts and open fires. Only one or two rooms had heating. The bathroom and kitchen walls and windows streamed with moisture and the solution was to open the window. A bit cold for a winter bath!
    So; to avoid condensation have the temperature inside your house the same as outside or the coldest surface you can find inside.The best way to achieve this is to open all the windows and turn the heating off! I guarantee the condensation will disappear. Alternatively you could insulate the floor and walls.

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