Condensation issues

Discussion in 'Builders' Talk' started by Helen2636, Jul 12, 2018.

  1. Helen2636

    Helen2636 Member yet annother problem with my house. Every single year we get the same issue....faint water lines when its cold coming from the ceiling edge to the carpet floor ( upstairs back bedroom right accros)

    3 bed 1960's semi.

    These marks are also present same location downstairs ( where patio doors are with a lean to conservatory off it) and yes flashing replaced.

    We have ZERO ventilation in loft, our gutters have no sofit vents either (old concrete gutters where angle grinded off but facia boards too narrow for sofit vents)

    If It was just a condensation issue I find it very odd it being in the same place downstairs.

    Oh the felt goes into the gutters so can't be a leek from there.

    We had a chap on the phone regarding this he mentioned installing a vent system in the attic....costly idea, but Would a few simple roof vents do the trick, with mybe a trickle vent (my newish windows never came with them.

    It really is the 1 thing driving me nuts and would like just 1 winter without this problem.

    I'm not very technical but struggling to solve the issue looking online as i dont think its damp.
    Any advice? 20180712_161643_resized.jpg 20180712_161636_resized.jpg
  2. rogerk101

    rogerk101 Well-Known Member

    In the dead of winter after a few really cold days, how much condensation is there in your loft?

    I had the same problem ... a 60s house with absolutely no loft ventilation and a tar-paper lined roof, so absolutely nowhere for any air to flow. Whatever condensation occurred in the loft (and there was a lot of it) was there to stay and accumulate.

    I started by installing 8 roof vents, which I bought from Screwfix (, and that helped a bit, but not by much. Oxford is not very windy, and these rely a lot on an air pressure difference between the high pressure on the winward side of the house and the low pressure on the leeward side to create a decent air flow.

    I then core-drilled out 8 150mm vent holes, 2 in each of the four gable ends, and that helped a lot more, as I now had even more openings so better air flow.

    Condensation still occurs on the underside of the tar paper after several days of freezing temperatures, but it tends to dissipate when the temps rise back up to above freezing.

    I'm striving for a bone dry loft that I can use for storage without the fear of damp and mould, so I'm in the middle of an experiment, and this next winter will be the acid test. I removed the tar paper from under the tiles in one area, in the hopes that this will allow much more breathing in the loft. I did it in an area where it would be relatively easy to replace the tar paper with breathable membrane if I have to, but time will tell if this is needed. I did this about half way through last winter and the signs are looking good that it's working.
  3. Helen2636

    Helen2636 Member

    Our gable end is on the opposite side of the consensation issue (gable end itself is annother hits the weather really bad...there is very little mortar left in between the bricks top half) annother issue Im having this rate I'll be knocking the bloody house down!) So I don't think placing wall vents on the gable end will help my situation. I've herd for some people the rooms get very drafty in winter. And our semi is set back from the other houses in the street not helping either.

    I have never looked in the loft over winter only to get the Christmas tree down I hate going up the half broken ladder...the loft also is an absolute bodge job up there. Nothing between the frame! Just looks like someone just stuck thin bords with masking tape :(

    The roof/ gutters are new....neibour did it so Ino it's not leeking. He said it was a mess, he could see our suitcases through it!

    I really understand how frustrating it is. We get really bad weather in the north west especially in winter.....thank God it' been hot for weeks to dry it out.
  4. Helen2636

    Helen2636 Member

    Oh and forgot to mention the condensation around the newish bedroom window is so wet in winter there are pools of water on the window ledge dripping on the floor!:(
  5. Astramax

    Astramax Well-Known Member

    Ventilation is a big help
  6. Astramax

    Astramax Well-Known Member

    5 years I decorated a flat that had black mould on four outside walls, it didn't help that the owner dried all washing indoors, over and in front of radiators causing the walls exterior to badly condensate up, walls were washed with bleach to kill mould and then painted with 2 coats Dulux Mouldshield Emulsion which solved the problem totally.
  7. Helen2636

    Helen2636 Member

    Rang a vent guy my mum recomended. She had out for annother issue. He's ment to be coming round tomorrow evening....but evey1s too worked up at minute. Been messed about loads by different workmen. When u work long hours and have children annoying when they don't show up.

    Just don't want him adding things on the job that don't work.

    Oh yes I've tried this when I had droplets on both walls and ceiling. I striped back the ceiling paint that had mould under the silk paint. Cleaned and half worked but then it was still on the walls. I was told by a guy who came Round a while ago. If you seal one area it will just find somewere else to stick to.

    If I painted the walls would the condensation just go somewhere else? Oh I never dry clothes on my rads I use maidens downstairs as its open plan.

    The back wall feels very cold in winter too.....we stupidly had cavity wall insulation....bad idea should never have been talked into it.....loose mortar, **** brickwork doesn't go hand in hand with it.

    Really hope I can get this sorted before winter, after 10 years, yes 10 years!
  8. Astramax

    Astramax Well-Known Member

    Another paint that does the same as the Dulux is called Crown Steracryl also costs a little less., over the years I have used both with excellent results. Condensation gathers on cold surfaces generally exterior walls are affected.
  9. Helen2636

    Helen2636 Member

    Ah right ok thanks for the tip. I only buy paint recomended rather than any old paint. I'll grab some once I've got some kind of ventilation. And let u know how I get on. Have u ever tried Johnston's damp paint, neibours used it for his walls and said It was fab....but it really stinks.

    I think I'll try adding a small wall vent on the back wall after reading the above reply. Mybe have a few less holes drilled through the vent. Whats the difference between a standard plastic wall vent and a passyfier vent. As I have cavity wall insulation would it interfere with it at all.
  10. Astramax

    Astramax Well-Known Member

    A pacifier vent goes through the wall with a telescopic tube fitting. The mentioned Dulux and Crown paint does not smell.
  11. Helen2636

    Helen2636 Member

    Well I'll give it a try!! Thanks for the advice :)

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