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    • CommentAuthorgoodevans
    • CommentTimeFeb 27th 2017
     
    Having looked at the style of a lot of houses I quite like the look of houses with a sharp look - in particular those with small/no eaves box and minimal overhang.

    I have not found a detail with this look that also incorporates EWI and over rafter insulation so I have had a preliminary crack at it below - any comments

    Things to note:
    a) rafter overhang cut as close as possible to the top plate to remove thermal bridge.
    b) air barrier anticipated to be at the osb level from top plate to top plate (below top plate wet plaster)
    c) with 50% of the insualtive value above the rafter is a vcl membrane required
    d) will the fixing of the soffet board to the rafter ends/osb through 200 mm of ewi be sufficient given that it is unfixed on its top half.

    Gable detail soon - in a separate topic.
      Eaves rev A.jpg
    • CommentAuthortony
    • CommentTimeFeb 27th 2017
     
    I don't like the drip bead and would far rather see facia overlap the render --- please

    I would like to see facia fixed to rafters
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    Yes, maybe you are right with the render under the facia, (not soffit or soffet!) - that would mean the render needing to go on before the roof tiles - would that be unusual? I haven't yet researched on the best order of construction I simply don't know yet.

    I had intended to show that the facia is connected to the rafter ends but through say 200mm of ewi. If the rafters are extended through the ewi the facia can be connected directly to the rafter but would still have a significant unsupported upstand. A gutter full of water is heavy and will try to peal the facia off the wall. The issue with ewi and over rafter insulation is that the gutter ends up a long way from the structural elements.
    • CommentAuthorowlman
    • CommentTimeFeb 28th 2017
     
    I bow to your greater knowledge in these matters tony, but the retro applied fascia board whilst possibly being the most practical doesn't give the architectural "sharp" look goodevans is after.
    How about a larger drip detail in Aluminium/SS right all the way up underneath the depicted rotproof fascia. Possibly even bonded to the fascia before fitting. Also maybe even accentuate the drip detail with a "recessed horizontal channel", all the way round the house.

    Just ideas?
    • CommentAuthorMarkyP
    • CommentTimeFeb 28th 2017 edited
     
    I dont see why you cant fit the fascia later. You have a tilt fillet which I think should meet the underside of the tiles. I dont think you need the vent grille. It's a warm roof so no ventilated void in the rafter zone, and plenty of air will get under the tiles and under the eaves without a vent. You can rest the bottom row of tiles on the tilt which should be sized to be the equivalent of a batten on a counter batten (timber yards stock these ripped from treated stock, standard detail for roofers). Use an eaves tray and then when you are ready tuck your fascia into place under it. Make sure your roofers allow for the fascia when calculting the tile overhang. I've done exactly this, no problems. You will need to carefully plan the fascia position relative to the render if you want no soffit, you might want to allow a small margin so your fascia is slightly proud of the render, you dont want to end up with render thicker than your fascia. A small 10 or 15mm overhang wont notice and you can fill this an expanding gasket if need be. This gives you a bit of margin on the render thickness and EWI fixing. Like Tony said, fix you fascia to the rafter ends. If you need a fixing at the upper end of the fascia you could maybe fix into the tilt, as well.
    • CommentAuthortony
    • CommentTimeFeb 28th 2017
     
    You would have to good to make a recessed horizontal channel work with out it "running out" nice idea though

    Generally all butt joints should be avoided by adding little steps for a multiplicity of reasons.
    • CommentAuthorowlman
    • CommentTimeFeb 28th 2017
     
    I was meaning make the horizontal channel part of the folded metal drip. not something just formed into the render, but I guess you could use possibly utilise an ashlar bead somehow.
    •  
      CommentAuthordjh
    • CommentTimeFeb 28th 2017
     
    Mount the gutter to the counterbattens, suitably sized and extended. No need for a fascia or drip beads etc at all.
    See e.g. AWI 06 - DAI 03
    • CommentAuthorowlman
    • CommentTimeFeb 28th 2017 edited
     
    Posted By: djhMount the gutter to the counterbattens, suitably sized and extended. No need for a fascia or drip beads etc at all.
    See e.g. AWI 06 - DAI 03


    AWI 06-DAI 03 ???

    I guess you could use also use side arm rafter gutter brackets, It may be a bit messy with the vent grille.
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    I like the counterbatton / no facia idea. That would look so sharp you could shave with it. I'm seeing the architect tomorrow goodness knows what he'll think - or the planners.

    ok djh - you've sold me the PH book - what is the formal title of the PH manual I need to buy with the PH accredited details - I don't want the wrong book - does anyone have a copy they wish to sell me?
    • CommentAuthortony
    • CommentTimeFeb 28th 2017
     
    You can borrow mine, mid Thames Valley area
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    Thanks - I'm Cambridgeshire - but I have to go to Heathrow on the 7th March - If I borrowed it would it be ok to post it back to you.

    What's the title? how much is a copy new. (I'm guessing its going to be steep as opposed to extortionate - after all PH is non profit making).
    • CommentAuthorgravelld
    • CommentTimeFeb 28th 2017
     
    Is this a new build?

    For the air barrier, are you worried at all about the plaster on the wall cracking? I assume it's on the external face because in the detail that's where the OSB touches.
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    no - if that OSB layer can act as barrier to the top plate I was then going to swap to the inside at the top plate and continue the barrier down into the wet plaster on the inside. If the plaster cracks it would need fixing - 90% of it would be visible so cracks should be visible.

    If a vcl is required on the inside of the dense insulation and under the roof that would have to be my air barrier (osb is then a structural only element ) - but a vcl at this location would not be punctured. I'm hoping a vcl would not be required as all layers are vapour permeable however it may concern a bco that the layers become less permeable the nearer to the outside they are.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 28th 2017
     
    Posted By: goodevansit may concern a bco that the layers become less permeable the nearer to the outside they are
    That was a rule of thumb that prevailed for a few years but my messing with WUFI suggests that it's neither necessary nor something to rely on.
    • CommentAuthorjfb
    • CommentTimeFeb 28th 2017
     
    Do you need a stop batten at the base of of the counter battens to help stop any potential slipping/sliding of the counter battens? Not sure how it fits in with everything else. Is it 200mm EPS on top of the OSB?
    What fixings are you planning on using for the counter battens?
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    I'm assuming there will be a bit less eps on top as I have insulation below to assist (although bridged by rafters).

    Fixing wise I have seen long helical headless nails/screws with a little hand held plastic cylindrical nail holder to ensure the nail goes in straight so at least one solution available. I have to leave some decisions till later - I'm just trying to find the show-stopper details that I don't have any solutions to at the moment.
    •  
      CommentAuthordjh
    • CommentTimeFeb 28th 2017
     
    Posted By: goodevansok djh - you've sold me the PH book - what is the formal title of the PH manual I need to buy with the PH accredited details

    http://www.google.co.uk/shopping/product/7685641428569009928?q=passivhaus+details&num=50

    Passivhaus-Bauteilkatalog / Details for Passive Houses: Okologisch Bewertete Konstruktionen / A Catalogue of Ecologically Rated Constructions

    Posted By: owlmanAWI 06-DAI 03 ???

    It's the detail number in the book.
    • CommentAuthorgoodevans
    • CommentTimeFeb 28th 2017
     
    Thanks djh
    • CommentAuthorringi
    • CommentTimeMar 1st 2017
     
    Is the book in english?
    • CommentAuthortony
    • CommentTimeMar 1st 2017 edited
     
    yes, mine is in both good English and German, but it is mostly sectional drawings
    •  
      CommentAuthordjh
    • CommentTimeMar 1st 2017
     
    There are a lot of drawings but there is more text than drawings. You can look at the contents at

    http://link.springer.com/book/10.1007%2F978-3-211-99497-9
    • CommentAuthorborpin
    • CommentTimeMar 1st 2017
     
    Firstly I'd thoroughly recommend Lindab Gutter. I bought the painted black, it's been up for 3 years and looks like it is brand new. They do a rafter bracket (quite long) and I think I'd be inclined to use that with no facia at all. What you do lose is the ability to put the 'felt' over an eaves tray which sits in the gutter so any water that runs down the felt ends up in the gutter.

    One concern is how you fit the tilting fillet. I ran some short stub rafters cut into the insulation. Steel roof but idea the same.
      IMG_0588.JPG
    • CommentAuthorborpin
    • CommentTimeMar 1st 2017
     
    And then
      IMG_0593.JPG
    •  
      CommentAuthorfostertom
    • CommentTimeMar 2nd 2017
     
    Stub rafters within the insulation overlay is a fine and flexible way of doing various things as reqd - supports the fascia board (if you must - I prefer none), can cantilever quite a bit for an attractive slim overhanging eave (verge too, similarly) in which case you just overlay the stub rafters with board(ing), leave the soffit open (and no fascia, just Lindab over- or side-rafter brackets - very substantial they are).)

    Is that lower Cellotex laid straight over the top of the structural rafters? If it wasn't, just cut between, then you'd have straight-through thermal bridge where the stub rafter sits direct on the structural rafter - then you'd have to hit-and-miss them - which can be done, will explain if anyone interested.

    Why you say the felt/eave tray can't drain into the gutter? Looks fine to me.
    •  
      CommentAuthordjh
    • CommentTimeMar 2nd 2017
     
    Yes, we have stub rafters (my architect called them sprockets) to give us 500 mm plus overhang on eaves and verges. They're quite unique in that every one is a different length and they are curved glulam parts. We don't have a fascia either and that resulted in one of the few negative aspects of the design. It had both myself and the plasterer swearing! I was painting the sprockets and the underside of the ply sarking board on top with a dark brown stain. He was rendering right up to them with cream-coloured lime. Both of us were swearing at the difficulty of working up into the acute angle of the eaves, especially when trying not to splash on the other's work.

    I have since had the render painted with Beeckosil but those painters managed to do a very neat job and I didn't hear them swearing. Maybe that's the difference with being a full-time painter

    But I don't think goodevans wanted overhanging eaves?
    • CommentAuthorborpin
    • CommentTimeMar 2nd 2017
     
    Posted By: fostertomWhy you say the felt/eave tray can't drain into the gutter? Looks fine to me.
    I meant for the OPs situation without a facia board.

    Posted By: fostertomIs that lower Cellotex laid straight over the top of the structural rafters?
    Yes so the only thermal bridge is where the 2 bits cross. 2x 75 thick then 150mm for the rest.

    Posted By: djhBut I don't think goodevans wanted overhanging eaves?
    No but if he wants the facia you just cut the stubs right back.
    •  
      CommentAuthorfostertom
    • CommentTimeMar 5th 2017 edited
     
    I meant to post up these pics to illustrate what I meant - you seen em before!

    The 6x2 structural rafters beneath the OSB are laid out to 'hit and miss' with these 4x3 doug fir stub rafters - needs planning. Hence the stub rafters are resting on 'nothing' but OSB. So their top ends are fixed to the 4x2 'runner' which bridges across the structural rafters. At the OSB eave junction, between the stub rafters we put 4x2 noggings (not shown) which bear at their mid points on the structural rafters.
      2011-07-26 044med.jpg
    •  
      CommentAuthorfostertom
    • CommentTimeMar 5th 2017 edited
     
    See the dark 3x2 'runner' fixed to the undersides of the stub rafters in this and the pic above? That's to suspend the 2x1.5 vertical battens of the boarded cladding - which then only need to be restrained horizontally (not supported vertically) by long screws thro the 150thk wall EWI (not shown - but the edge of the roof 100thk 'EWI' is visible).
      2011-08-19 040med.jpg
    •  
      CommentAuthorfostertom
    • CommentTimeMar 5th 2017 edited
     
    Here's the airtight/vapour breatheable OSB tea-cosy glued and screwed, external so not penetrated by joists etc etc.
      2011-07-26 021reduced.jpg
   
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