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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorPaul_B
    • CommentTimeJan 3rd 2015
    Good evening all and belated Happy New Year,

    A considerable amount of time has past since I last posted to the forum, but I am once again seeking the forums collective advice. I have a cloakroom that suffered with condensation and mould since we moved into the house eight years ago. On one side of the cloakroom (left hand side in the picture below) is the kitchen on the other side is a void under the stairs and then a internal wall to the integrated garage. So warm humid on one side and cold on the other. The room has no extractor fan.

    The integrated garage has what I presume is lightweight block to the rest of the house. I parge coated the wall taped the wall to ceiling and wall to floor then insulated the wall on the garage side with 50mm celotex foam. I taped again the wall to ceiling and wall to floor, before gluing (continuous bond) and fixing 12.5mm fermacell. The wall has breaches for internal vacuum, boiler drainage and water supply. These penetrations have been filed with fire grade foam.

    Removing the plasterboard and non-continuous dabs I have discovered significant drafts coming from the window surround and from behind the plasterboard in other rooms. The stud partitions are metal and voids exist between rooms. Finally after removing part of the ceiling I found a huge gap in the wall next to a joist as well as smaller gaps next to other joists.

    Pic of room:

    Pic of staircase void

    Pic of joist gap

    Other pics

    So here is my plan for remediation:
    Fill gaps between joists with expanding foam
    Fill gaps between metal studs and walls with expanding foam
    Fill void between staircase and external wall with expanding foam
    Parge coat the external wall in the cloakroom and staircase void
    Parge coat internal wall attached to kitchen
    Parge coat internal wall between staircase void and garage
    Tape wall to ceiling, wall to floor, joist to wall, window frame edge plastic to wall
    Insulate external walls with 50mm celotex, cloakroom and staircase void
    Insulate internal side of garage wall with 50 mm celotex
    Insulate floor in staircase void to same depth as cloakroom floor, approx 10cm of XPS??
    Insulate void created by stud work with 35mm celtoex
    Tape wall to ceiling, wall to floor
    Re-line all walls with 10 or 12.5mm fermacell
    Around the window I plan to use some left over spacetherm (aerogel) 5mm or 10mm can't remember what I have left
    Fit a single room heat recovery fan

    Anything else I should do? Anything I should not do?

    Many thanks

    Looks like you got it covered. You are sealing the draughts, insulating the cold walls and putting in the ventilation to keep the humidity down. Sounds good to me. Only thing I might add would be an anti mould treatment as well
    • CommentAuthortony
    • CommentTimeJan 4th 2015
    Cripes well done! who built it! :cry:

    Good plan to do the air tightness, can I use your joist pic with the wooden wedge please on my website (DraughtBusters.net)

    The blocks are my favourite type, medium density recycled aggregate and nice and strong, not prone to cracking, I would fill all gaps and cracks prior to parging.

    Good idea to insulate, unfortunately condensation has a mind of its own and will go and single mindedly find the coolest places where rh reaches due point and dump there. your job is to stop it doing that.

    HR fan good idea, whole house system would sort it.

    I reckon that you will have chased it out of the WC, is there any heating in there, if not I reckon you may do well to have some.

    not so happy thoughts -- what about the rest of the house -- http://readinguk.org/draughtbusters/?page_id=45

    I am longing for the day we can go after the people responsible for getting us in this mess, the worse thing is it is still happening today on new builds. :cry::cry::cry:
    • CommentAuthorPaul_B
    • CommentTimeJan 4th 2015
    All thanks for the comments and opinions.

    Tony, no problem using the pics, please let me know if you have any difficulties saving them.

    Additional background is the house was built in 1998 by McLean Homes and on the surface appears to be "well" constructed and the estate locally (just outside Eastbourne) is considered to be "premium" build. An example being foundations at twice the depth to the rear as the front due to an Oak tree at the rear of the garden and located on weald clay, the windows are double glazed with rubber seals. I guess what it shows is the contractors will try to get away with cutting corners unless someone incl. BC are checking up on them, or the are incentivised to do a better job.

    I forgot to mention one other thing in my original tale of horrors that I discovered and that is under the sink they obviously couldn't find the wood plinth to attach the sink, so they created some huge holes in the plasterboard.

    Under-sink holes:

    In terms of heating I'm mulling over if I should include a radiator or towel rail. The reality is a towel is needed in the cloakroom but if this is placed over the radiator is this going to cause more humidity problems? I will include a humidity sensor in the room for home-automation and this will monitor the dew point and control the heat-recovery unit.

    Lastly if including heating should I insulate the wall to the kitchen to basically isolate the room or would it be beneficial to leave it uninsulated and make use of the heat bridging from the kitchen?

    I would never have gone to these lengths if I hadn't come across this site and would imagine most people would have just used mould resistant paint to treat the effect leaching un-necessary chemicals and an extractor fan, loosing more energy in the form of heat.

    As for the rest of the house I now know I am going to need to do each room one by one. The next problem area is the integrated garage as the room above always feels cold.

    • CommentAuthorPaul_B
    • CommentTimeJan 4th 2015 edited
    Posted By: tonywhat about the rest of the house --http://readinguk.org/draughtbusters/?page_id=45" rel="nofollow" >http://readinguk.org/draughtbusters/?page_id=45


    This is a great resource and shows all the situations I have so far encountered in my own home. I'll continue taking pics and making them available pre and post remediation. Can I reference the site and quote advice on Eastbourne Community Energy website? A year ago myself and four other people came together to establish a community energy co-op in the Eastbourne area to raise awareness, projects and renewable energy schemes. We are hoping to launch our first major PV project this year and the intention are that all profits are invested back into the community to improve energy efficiency and energy awareness. A couple of the directors are also involved with transition town Eastbourne.

    • CommentAuthortony
    • CommentTimeJan 4th 2015
    Wonderful!! Yes please feel free to do what you like with the DraughtBusters site address.
    • CommentAuthorgravelld
    • CommentTimeJan 4th 2015
    Tony, did you ever develop some more procedures for dealing with the first floor void as mentioned in your page above?
    • CommentAuthortony
    • CommentTimeJan 4th 2015
    Yes, myself with Andy, see http://readinguk.org/draughtbusters/?page_id=268.

    I would like to further develop a simpler less disruptive process if anyone is up for new business opportunity
    • CommentAuthorgravelld
    • CommentTimeJan 6th 2015
    How could it be less disruptive? You need access to the joist ends, I don't see how else you can do it. Unless you mean NANO ROBOTS FROM THE FUTURE.
    • CommentAuthortony
    • CommentTimeJan 6th 2015
    :smile: thinking of patents but happy to share on non disclosure basis
    • CommentAuthorPaul_B
    • CommentTimeJan 10th 2015
    A couple more pics from the void under the staircase. I assume the XPS should be in the void instead of missing as shown with nice draughts coming through the blocks in the floor? Plan on removing the scree to get back to the XPS somewhere between the void and hopefully the cloakroom.

    Shot 1

    Shot 2

    Shot 3

    Also had another surprise when removing the plasterboard, looks as though the insulation wasn't the only thing here corners were cut. Thankfully I didn't get a nasty shock!


    • CommentAuthorPaul_B
    • CommentTimeMar 15th 2015
    The cloakroom is coming along slowly due to work commitments, only getting about a day a week to do anything useful.

    I have sealed up the many voids under the stairs and used foam as well as tape to reduce air leakage / entry. Appreciate any comments especially around the type of insulation to use on the floor of the void under the stairs which is normally inaccessible. I was thinking warmcell or EPS beads, but maybe I should match the existing insulation and go with XPS?

    Filled gaps into the integrated garage:

    Void Floor:

    Window detailing:

    Finally, after blocking the large voids some of the smaller ones become more apparent. This is the junction of the internal wall and external wall and I could feel with my hand a cold draught. The pic shows the small amount of "spoil" that was the mortar. Now removed and foamed, next will be the parge coat:


    • CommentAuthortony
    • CommentTimeMar 15th 2015
    Your country needs you! Such a nice job! Is that a clue on the stairs?
    • CommentAuthorPaul_B
    • CommentTimeMar 15th 2015

    Lol I wish! Every time I do work in the house your comment of living in a tent echo's in my head. So true

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