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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorslidersx200
    • CommentTimeNov 4th 2014 edited
    Having joined the forum just over a year ago, I've probably been a bit quieter as of late and that is mostly because I've been dedicating a lot of time to researching and refining the processes for my own build. Things got going on site at the end of June and although we'll set no records for speed, especially compared to timber frame builds, I'm pretty happy with the progress we've since made and feel that the pace affords enough time to make adjustments as new things come to light.

    The roof trusses are due to arrive on site this Thursday and hopefully we can get things pretty weather tight before the predicted severe winter sets in.
    Parabolic arch for French doors
    Web floor joists
    • CommentAuthorslidersx200
    • CommentTimeNov 4th 2014 edited
    225mm cavity (and yes the dropped wall tie was retrieved!)
    • CommentAuthorMackers
    • CommentTimeNov 4th 2014
    How sturdy do you find the webbed joists? Look very good, keep the good work up
    It's hard to say just yet as the 22mm floorboards are responsible for contributing to the overall stiffness, but they won't be installed until they can be protected from the elements. We have 254mm joists on 600mm centres and they are supported on a timber trimmer by the top chord. The span is ~5.3m and you can see maybe 10-15mm deflection if you bounce on the middle of one beam, but when boarded, the load will be distributed across 2-3 joists.
    • CommentAuthorDarylP
    • CommentTimeNov 5th 2014

    Who did your SE calcs for the metal web joists? I ask because we had to overspec beyond what the mfr offered. to 406mm at 400c/cs 5.4m span.
    They still bounced a little, with 22mm glued chipboard finish , herringbone straps @ 1/3 span and strongback, but the p/b ceiling stiffened it up nicely.:smile:
    • CommentAuthorslidersx200
    • CommentTimeNov 5th 2014 edited
    The design work was all done by the manufacturer in our case, they came to measure the as built structure and once the installation detail was finalised, did all the calculations. I did query the movement once I'd seen it (was on holiday when the joists were installed) and the designer told me that their system will not let them proceed with a floor that isn't up to spec.

    There are only two rooms that have the full 5.3m span without a supporting wall below, so hopefully we will get away with it!

    I originally wanted to use 219mm joists to increase headroom upstairs, but we didn't need to as it turned out that the natural coursing of the block work has made the wall plate level a little higher. The 219mm joists would have worked at 400mm centres, but this route was quite a bit more expensive and gave less room for running services.
    • CommentAuthorborpin
    • CommentTimeNov 5th 2014
    Posted By: slidersx200The design work was all done by the manufacturer
    Who was the supplier? Look an interesting system but why such a big 'joist' (trimmer?) at the end? How is the bottom element of the joist joined at the end?
    • CommentAuthortony
    • CommentTimeNov 5th 2014
    hung there
    • CommentAuthorborpin
    • CommentTimeNov 5th 2014
    Posted By: tonyhung there
    • CommentAuthorDarylP
    • CommentTimeNov 5th 2014
    They look like top-hung joists. The bearing is the top chord, the bottom just butts up against the plate.

    • CommentAuthorborpin
    • CommentTimeNov 5th 2014
    Posted By: DarylPThey look like top-hung joists. The bearing is the top chord, the bottom just butts up against the plate.
    That was what I could see but wondered if I was right. Are these used in TF buildings at all? Just thinking there is minimal cold bridging, you could build the frame such that the joist was directly over a stud (as they should be anyway) and just a normal frame for it to sit on. Does it rely on the 'butt' for stability - can't see that it does. Just thinking.... Nice for services.
    I have metal web joists in my I-beam timber frame. The top flange of the joist sits on the top of a wall plate which is screwed to the I-beams. The wall plate is also supported by vertical battens nailed the the I-beams. The bottom flange of mine don't butt up closely to the wall plate. The top flange is screwed to the top edge of the wall plate. There are strongbacks fitted to prevent twisting or movement?
    The joists were made and supplied by a company called Murdock's. They are a fairly large chain of builders' merchants in NI and also make roof trusses and web joists etc.

    I tried to adapt the construction detail used at the Denby Dale Passivhaus to use cheaper materials and hopefully provide a more robust result. The trimmers are standard 9x2 timber that the supplier ripped to the correct size to line up with the bottom chord of the joists so there is somewhere solid to fix plasterboard to. The joists hang on the trimmer and are nailed to it at the bottom, saving a few hundred pounds on hangers and hardware. The trimmer is just bolted to the wall using "thunder bolts" and the holes were injected with sealant before the bolts were fitted.

    We cut a roll of airtight membrane to ~50cm wide and ran that around the perimeter walls before installing the trimmers instead of using a large coat. It will be keyed to the wet plaster finish above and below when the time comes.
    • CommentAuthorslidersx200
    • CommentTimeNov 5th 2014 edited
    125mm PIR closes the cavity at the reveals. The inner leaf is returned slightly to meet the PIR and some reveals are splayed at 30 degrees. You can also see the row of Quinn Lite blocks at the base of the inner leaf. These are laid on top of the DPC and fall in the same plane as the floor insulation to improve continuity between the wall and floor insulation.
    Granite cills designed for timber frame construction will help to reduce cold bridging at the base of the windows.
    We curved one of the walls in the hallway to help get natural light into the centre of the house, improve access for anyone of limited mobility and hopefully invite visitors towards the living room/dining area.
    Looking a bit different now and the slates should start to go on next week. Work just started today on fitting the counter battened roofing membrane and slating battens.

    Windows and doors ordered, due in approx 5 weeks... cue typical TV programme glazing delays!
    I also used the web floor joists. Generally I am happy with them but sound transfer is still a slight problem!! Espacially with a young family of elephants running around until the peace and quiet of 7-30pm.

    Not that I am clock watching though :bigsmile:

    Looks like a good project.
    Almost weather tight
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