Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



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.

Buy individually or both books together. Delivery is free!


widget @ surfing-waves.com




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




  1.  
    We've had a photograph of a country band on our wall for years, standing in front of a 'tin tabernacle' that we sometimes pretend are our in-laws (the band, not the tabernacle). After a holiday in Wales where we saw several more, and doing some research, it seems that these simple timber and metal buildings have stood for upwards of 120 years with minimal maintenance. I was wondering if anybody had any thoughts / pictures of how the corrugated metal might be detailed, particularly on the sides of windows? From my observations, they seem to be timber framed, with the timber flush against the corrugated metal.
  2.  
    For example this one from Pembroke:
      IMG_20180527_181943.jpg
  3.  
    Here's another from nearby Pembroke Dock.
      Pembroke Tin Tabernacle.jpg
    • CommentAuthortony
    • CommentTimeJun 3rd 2018
     
    The corrugated sheet should touch the window lining and now we would silicone the joint before fitting the architrave which covers it.

    Under the sill the sheet should be housed into the sill 10mm and the sill should have a good drip groove.

    I hate with a vengeance the head detail you show, it is a sacrificial piece of wood, it really needs a small flashing that goes behind the corrugated sheet down the drip trim and when it finally turns down over this the drips should normally fall clear of the window sill. It too should have a drip groove. In its favour the gutter has been protecting the head quite a bit, but looks to be leaking now.
  4.  
    Thanks Tony!
    Posted By: tony
    The corrugated sheet should touch the window lining and now we would silicone the joint before fitting the architrave which covers it.

    How would the architrave work / keep out the water if the metal is corrugated? Wouldn't it need some kind of flashing that comes behind the corrugated metal as well?

    Posted By: tony
    Under the sill the sheet should be housed into the sill 10mm and the sill should have a good drip groove.

    I was thinking that the edges of the sill sheet should also be turned up, and come behind some kind of flashing on the sides of the window.

    Posted By: tony
    I hate with a vengeance the head detail you show, it is a sacrificial piece of wood, it really needs a small flashing that goes behind the corrugated sheet down the drip trim and when it finally turns down over this the drips should normally fall clear of the window sill. It too should have a drip groove. In its favour the gutter has been protecting the head quite a bit, but looks to be leaking now.

    I think my photo doesn't quite do it justice. I don't seem to have a picture from the profile. There seemed to be a small piece of metal forming a drip detail above the timber, if not on this tin tabernacle, on one of the others.
  5.  
    'See
      window header.jpg
  6.  
    and
      door header.jpg
    • CommentAuthortony
    • CommentTimeJun 3rd 2018
     
    Head on the door was better, needs replacing now, best if it goes to the outside of the architrave.

    At the sides, the architrave protects the join and water goes down so fast there were no problems in 100 years without silicone so OK

    Sill seems OK, the notch is important so it horns round the sheet at the sides

    It is all very simple but has stood the test of time very well. Looks like the head flashing was steel sheet would be better as lead, copper or plastic.
    • CommentAuthorbarney
    • CommentTimeJun 3rd 2018
     
    A few years back, I worked on the design of a new hospital and on the site were a number of single story ward building very much like a tin tabernacle.

    These were erected in anticipation of heavy casualties of Canadian troops on D day - and were known locally as the Canada wards

    They were thrown up using German POW labour - basically a simple single 9" brick foundation with ashcrete slab topped with sand and hot bitumen screed (to reduce noise)

    4" x 4" primary frame in timber - intermediate 4" x 2" framing and a wriggly tin roof and walls - internal insulation was sheep wool and lined with T&G boards. Roof trusses were manufactured on site scissor type trusses

    I watched them coming down and they had circa 4" sheet steel flashings to the sash window reveals (under the wriggly tin) - interestingly they has sheet metal cills sat on a rough sawn wooden block - turned up to sit behind the sheets and the vertical flashing. Similar detail at wall corners and a slightly different welted arrangement at the bottom of the sheets (these overhang the brickwork about the depth of a brick)

    No head detail as the windows went right up to the wall plate and were protected by the roof overhang/guttering etc - ditto the doors

    There was a moulded architrave as you show to finish the window splay - but entirely sacrificial (and in perfect order when we took them down)

    The sheets were all painted in what appeared to be the sort of zinc rich paint used for painting transformers etc by the former electricity boards

    They were in remarkable condition given they were only ever erected as temporary buildings by POW labour and were about 50 years old when we removed them (several were dismantled and re used elsewhere when we advertised as free to a good home - with almost no attention required when they were re erected.

    If you want a bit more info on flashing etc, take a look at the example of the Norwegian Churches that are at Swansea and Cardiff docks

    I'm a big fan of wriggly tin - perhaps because I spent part of my childhood living in a wooden house with a tin roof and upper walls. The building was originally (I believe) an old field barn that was raised up to give a first floor and then clad down to the original stonework level

    The sheets had decades of black bitumastic paint applied - the considered wisdom being this was best done "hot" - so a summer job. I had the worst burning of my life when I decided that the suitable attire for the task was lemon juice on the hair, coconut oil for the body, cut down denim shorts and doc martens - at least the coconut oil made it a tad easier to remove the black bitumen splashes (with thinners !!).

    Regards

    Barney
  7.  
    Posted By: barney
    I watched them coming down and they had circa 4" sheet steel flashings to the sash window reveals (under the wriggly tin) - interestingly they has sheet metal cills sat on a rough sawn wooden block - turned up to sit behind the sheets and the vertical flashing.

    That's really helpful information Barney. Many modern day flashings seem to come over the corrugated sheet instead. Was there any depth to the reveal? If so, I'm assuming that the corrugated sheet was bent around the corner to form the reveal. And do you know how they sealed between the flashing and the window at the sides?
    Posted By: barney
    Similar detail at wall corners

    That's interesting. I understood that some tin tabernacles simply had the sheets bent around the corners.
    Posted By: barney
    If you want a bit more info on flashing etc, take a look at the example of the Norwegian Churches that are at Swansea and Cardiff docks

    Thanks - I'll check them out when I have a bit of time.
    Posted By: barney
    I'm a big fan of wriggly tin - perhaps because I spent part of my childhood living in a wooden house with a tin roof and upper walls. The building was originally (I believe) an old field barn that was raised up to give a first floor and then clad down to the original stonework level

    My childhood bathroom was also a shed with a bit of wriggly tin until we knocked it down and turned it into an extension of the kitchen. All the galvanisation had washed off and it was a rust colour.
    • CommentAuthorbarney
    • CommentTimeJun 4th 2018
     
    Almost no reveal depth, what you could see was the L shaped flashing, which returned behind the sheet.

    I think the flashing size ensured at least one corrugation was in tight contact to the steel surface so other than capillary action any water driven in simply tracked to the bottom and out

    If you imagine every internal corner (of door and window reveals and every external corner of the building had a top to bottom steel angle added and the sheets plonked on top

    There might have been a daub of putty added to the sheet rear as it was offered up to that steel angle

    No bent sheets used at all (looking at the gauge, they would have been a right hassle to bend anyway) - sheets were all trimmed to corners with the flashing underneath rather than over

    I did find old archive drawings of the huts - but they seemed to be general arrangement plans of layout to make sure the bed spaces worked rather than detailed construction drawings

    regards

    Barney
    • CommentAuthortony
    • CommentTimeJun 6th 2018
     
    I can’t see how an L side flashing could possibly direct the water out again, it finishes behind the corrugated sheets
    • CommentAuthorbarney
    • CommentTimeJun 6th 2018
     
    Sure Tony - I presume that the small amount of water driven in horizontally quickly loses velocity and gravity takes over - the flat vertical steel surface just allows the water to run rapidly to the bottom and out behind the sheet (and over the brick plinth so not touching the sole plate

    Difficult to be sure but it looked as if there was a strip of putty roughly thumbed onto the flashing, the sheet was offered up and nailed into place - there was evidence of this putty in the laps of the sheets as well

    As I said, at the windows, it overlapped the tin cill - so water at window reveals ran down onto the cill and out

    There are plenty of metal cladding systems that use a flashing under the sheets

    Regards

    Barney
  8.  
    Posted By: barney
    Difficult to be sure but it looked as if there was a strip of putty roughly thumbed onto the flashing, the sheet was offered up and nailed into place - there was evidence of this putty in the laps of the sheets as well


    I've seen a few window flashings that use the equivalent of a strip of putty - a strip of foam rubber or similar that would prevent any water being blown at any velocity sideways between the metal surfaces.
  9.  
    @Barney, do you recall what happened with the side flashing (green)? I can see that it would go over the sill (red), but how did it end at the bottom? I've tried to interpret your description, but it seems that there might be a ingress point on the corner.
      20180607 Corrugated Iron Flashing.jpg
    • CommentAuthorbarney
    • CommentTimeJun 7th 2018
     
    The green flashing continued right down onto the cill - Bring the upstand on the side of the cill a bit further forward to sit right in the angle of the green flashing. Then add horns on the cill also with an upstand. Think of a a masonary cill where it has ends that sweep up to flat for the brick courses. Sheets notched out so the sat onto the horns.

    I suspect the construction sequence was fist to erect the 4" x4" window posts and the corner posts - then add the horizontal timbers to make up the gap under the window and position the cill then add the side flashings - then drop the sash windows in place, add the putty beads and bang on the sheets

    I'm not sure anyone would say it was an exemplar wriggly tin build - they were erected by POW labour to provide casualty stations for injured troops post D-Day. I believe the plan was to run them up the Bristol channel so as not to impede fresh men and material heading out and then move them to the relevant locations by truck/train running "north" presumably empty to get material from the industrial midlands ready for a full trip south again

    A sort of "fresh men and material going out and casualties coming back" strategy. In any event I believe that the extent of casualties was not as bad as predicted but the sites across parts of south wales and up through Hereford and Worcester were certainly used - and in some cases right up until fairly recently.

    I can see that dropping the side flashing onto the cill being a weak point, but evidently it wasn't a problem in practice as none of the huts showed any discernible water damage to the framing etc after a good few decades.

    Someone was obviously used a sheet metal folder and a minor bit of welding (or possibly brazing) to form those cill assemblies - quite possible a small firm making them to a standard size and fitting in production runs between making other metal bashed stuff for the war effort - I saw identical units on several sites. Possibly a case of making things simple so unskilled (or unwilling) labour could put them together easily

    I'll try and sketch the cill out if I've got time later

    Regards

    Barney
    • CommentAuthorbarney
    • CommentTimeJun 7th 2018
     
    Try here:

    http://spectrumarchitectural.com/aluminium-window-cills-and-pressings/

    Type 2 is similar to the sheet steel cills, but with "horns" at each side, all with upstands

    I've only recently thrown an original one away - I had it stuck on the front of my greenhouse to make it easier to wheel a barrow in and out occasionally - I'd estimate it to be about 18 gauge (say 1.25mm) - so pretty tough things when added over a wooden block

    Regards

    Barney
  10.  
    Thanks Barney! The diagram was meant to be an exploded diagram so you could see what went where. I'll check out the link you posted later. Do the upturned cill corners continue onto the overhang, or just in the reveal?
  11.  
    @Barney, is the Type 3 in the link you showed more of what you meant? It seems to have upturned edges.
  12.  
    Posted By: barneySheets notched out so the sat onto the horns.

    I'm not sure what you mean here. Sounds like an important detail.
  13.  
    There is some detail on corrugated metal cladding from NZ set out here: https://www.buildmagazine.org.nz/articles/show/horizontalprofiled-metalas-a-cladding
  14.  
    Here's another link from NZ that says horizontal corrugations need counter battening to provide an air gap, whereas vertical corrugations can be fixed directly: https://www.weathertight.org.nz/new-buildings/detail-solutions/wall-cladding-selection/profiled-metal/
    •  
      CommentAuthorfostertom
    • CommentTime5 days ago
     
    I also love true 'corrugated iron' i.e. the 3" x 3/4" classic type - and equally hate just about all more modern profiles.
  15.  
    I've encountered the dilema of what to do at the sides when building sheds at home.
    Using second-hand window frames the corrugations inevitably don't meet the frame at a convenient point in the curve, nor the same point each side.
    What I've done is bend the metal so that it turns outwards against the side or front face of the wood, apply sealant to the mating faces and then nail the metal with short clout nails about every 3" or wherever a stubborn bit wanted to stand proud.

    Looking at an old tin community hall in Somerset I was interested to see the same method used. A drip-strip of flattened tin along the top is a good idea, although this hall didn't have any - drips just splashed off the wooden cill below.

    There's always problem what to do at the corners. The easiest is just to fold the sheet round in a sharp 90 degree bend, but that doesn't always work neatly if it comes at the wrong point of the corrugation. One solution is to start a new sheet, hammered flat and bend round a few inches, with the other side sheet nailed overlapping it. If you use an angled corner piece it never coincides with the corrugations so rain can blow in sideways.
    • CommentAuthorbarney
    • CommentTime5 days ago
     
    Typically, for 13/3 corrugated sheets, the side flashings are around 200mm - so basically, regardless of where on a sheet you need to cut, you always have enough raised or lower profiles left to pretty well ensure the water can't enter due to the number of troughs and peaks - you can buy mastic beads with a tear off tape in a roll to use along the peaks.

    Personally, I bloody hate the side flashings over the sheet - the secret is to use a combination of the sheet overlaps (I usually aim for 2) and counter batten details so you always end up with full sheets at edges - and I like to put the flashings below.

    It's no different to setting out the building to brick dimensions if you want to avoid all the horrible cuts on the face work.

    Bending sheets around the corner is just typical "farmer" style in my book - if you set out the building correctly, then it's unnecessary (similar comments for the roof, although with a bit of thought and a few rolled profiles you can again finish with full sheets and a concealed flashing detail that allows full weatherproofing whilst not appearing to wrap a section down from the roof over the eaves.

    Like Tom, I like the honesty of wriggly tin - I just don't want it to look like some farmers lambing shed

    Regards

    Barney
  16.  
    "Bending sheets around the corner is just typical "farmer" style in my book"

    I agree. But not as bad as switching to horizontal to avoid cutting diagonally, or to cover awkward bits over doorways etc. :)
  17.  
    Posted By: barneyPersonally, I bloody hate the side flashings over the sheet - the secret is to use a combination of the sheet overlaps (I usually aim for 2) and counter batten details so you always end up with full sheets at edges - and I like to put the flashings below.

    I totally agree. They look rubbish. I much prefer the look of flashings below. The industrial metal sheds that you see nowadays always seem to have the flashing outside the corrugated sections (and the corrugated sections are always nasty square ones).
  18.  
    Lots of the tin tabernacles seem to have Gothic arches in the windows, with the frames protruding past the cladding. I wonder how the flashing is done?
  19.  
    Posted By: barney
    Bending sheets around the corner is just typical "farmer" style in my book

    To be fair to Cliff, it looks like many of the original tin tabernacles bent the cladding around the corners.
    • CommentAuthortony
    • CommentTime2 days ago edited
     
    Probably with putty and paint and knowledge that water runs down hill. Hopefully there will be a strip of metal on the top of the frame to keep water off it with a slight upturn on it but it wouldn’t surprise me if there wasn’t anything.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press