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Loft Rafters - White Spot Mould + Damp

Discussion in 'Wood / Woodwork / Carpentry' started by meditatinghamster, 6 Dec 2008.

  1. meditatinghamster

    meditatinghamster

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    Hi, I recently moved into an 85 year old house that turned out to have 'White Spot Mould' on the rafters. At first I thought it was Wet Rot from looking at pictures on google, but on inspection by a reputable company I was told it was white spot mould. The rafters are a little soft but on prodding with a screwdriver it appears to be very superficial. I can only prod in by about 1mm.

    I blame the loft hatch as it appears to be the loft hatch side of the loft that is affected the most, and I've seen lots of condensation building up on the tiles after we've had the heating on high.

    The company we had take a look quoted £350 to treat the mould and said we need need to be out of the house for one hour while they treat. This seems a bit overkill, but I do want to sort the mould out and protect the rafters.

    This might seem a bit nuts, but I was thinking i could just

    1) use some household mould and mildew remover that we would normally use on the bathroom tiles. The mould seems to come away easily with tissue. (I assume bleach would be a big no-no as it would damage the wood?)

    2) Then wipe the beams down with a dry cloth.

    3) Put the dehumidifyer up there to get rid of the moisture and dry the rafters.

    4) Treat all the wood in the loft with something that would help protect it in the future. I just have no idea what though. Can you varnish rafters or use any kind of wood hardner, or even paint them with with wood gloss?

    I will be sorting out the cause of the condensation build up, but would be really grateful for advice on the above. With the rafters playing such an important role I look after the wood properly.

    I'd be really grateful for any advice anyone could offer on this.
     
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  3. JohnD

    JohnD

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    lofts are normally kept dry by ventilation, and by preventing warm moist air from rising up there.

    Check the eaves are not blocked by insulation, most old rooves are quite draughty so should be OK.

    Check that you loft water tanks have covers on them and are not warm and that hot water does not come out of the vent pipes

    Look for cracks or holes in ceilings (e.g. round pipes and light fittings) allowing warm air to leak up, especially from the bathroom, and especially if an extractor fan is not used in the bathroom

    Draught proof the loft hatch

    If you are in the habit of draping wet washing and towels about the house, or over radiators, your house will always be damp and will not be cured unless you change.

    Having dealt with the damp which encourages and permits rot and mould, it will stop growing and chemical treatment should not be necessary unless you want to.

    It is more usual to treat timbers with a timber preservative than with bleach or household cleaners. I use Cuprinol Green which is the best-known. I am told that wickes own-brand is similar and cheaper. You will need plastic (not rubber) gloves, and protective mask, goggles, hat, overalls etc.
     
  4. anobium

    anobium

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    Sounds like it is the residual effect of somebody treating the roof previously with either a fungicide or insectcide.
    This is quite a common problem but to be on the safe side check with the previous owners for any records pertaining to works in the roof.
    Dont spend money on having it treated complete waste of time.
     
  5. meditatinghamster

    meditatinghamster

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    Thanks for that, looks like treatment is a complete waste of time in this particular case. I must have spoken to loads of people now who have said that this will just go away once the source of the condensation on the tiles is sorted out. Below is what it looks like.


    What doesn't help is that the spot lights for the bathroom can be seen through the scraggy loft insulation, i.e you can see them lit up through the insulation when the the bathroom lights are on.
    There are five of these and they're 50W each and get red hot very quickly. I'll be sorting that out!

    Loft hatch needs insulating and the joist insulation replacing + some kingspan on the rafters.

    Hell, there weren't even any boards in the loft until this weekend (I finally realised getting the old loft insulation out might be easier if I get some boards up. Doh!).

    There is no ventilation in the bathroom so we need to fit an extractor in the batroom.

    If we've still got any pennies left when we're done, we may go for wall cavity insulation also.

    We don't tumble dry eveything and are guilty of having washing drying on the clothes horse. Could do with a green house outside just for the clothes!!!!

    What the world needs are special tiles or blocks that are actually a complete vacuum inside. That would solve the conduction side of heat loss :D
     
  6. JohnD

    JohnD

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  7. meditatinghamster

    meditatinghamster

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    definitly think dehumidifyers are worth a mention.
     
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