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Roof design issue

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Comments

  • #32
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    Deleted User wrote: »
    Oh it'd be a big enough job, but would be a much better use of the space. I still wouldn't bother with an architect or engineer though. Get a good builder that you can trust. Builders are at it all day, every day. If you get someone that's personally recommended honest they won't rob you blind, and they'll know how to do it without an instruction manual from an architect.


    However, it seems the aesthetics aren't really the issue here, anyway. If I were you, OP, I'd re-do the roof (be less than €5k I'd say) and re-slab the inner walls with a decent insulated plasterboard. Should sort out most of your problems, I'd say.


    For what it's worth (and i'm aware I'm gonna get a load of posts on how wrong this is) I have an extension with cavity blocks (not a cavity wall, just cavity blocks), and it's insulated internally with insulated plasterboard, around 50mm thick (I wanted to go thicker, but getting insulation was a problem at the time).


    The ceiling was insulated and roof done by a local roofers (flat roof, felt).


    The place is roasting after a few minutes of the heating being on, and if you knock the heating off, the heat holds for a fairly reasonable amount of time. The house itself is a cavity-wall build, and it has not gotten any colder with the extension being added on (we opened up the kitchen).


    So with that in my mind, that I have a very comfortable extension with fairly low specs, I can't understand how yours is so cold. Is it void of any insulation at all? Did they just do a single-leaf wall, render the outside and plaster the inside, and skip the insulation step altogether?

    The builder definitely cut corners. For example his drawing claims a 110mm pumped cavity but it's 90mm and I personally don't think the blocks are sealed as the drawing claims 20mm nap plaster under white finish but it's not there. 2mm of the white stuff was slapped directly on to the blocks.


  • #33
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    the_pen_turner wrote: »
    whats the theory behind that. is it moisture transfer they are worried about or ventilation.

    could spray foam work instead like they do on a roof. that is regularly put around timber.

    if not then the ceiling will have to come down and bridgers come out an insulation put in properly.
    why didnt they take down the ceiling and fix it before putting up a new ceiling

    The beads are only suitable for block to block due to pressure when pumping.

    Cost I'd say


  • #34
    the_pen_turner
    Registered Users Posts: 7,505 ✭✭✭the_pen_turner


    Ginger83 wrote: »
    The beads are only suitable for block to block due to pressure when pumping.

    Cost I'd say

    would it create that much pressure. a 9x 2 with even 3 gun nails on each side would hold an amzing amount of pressure. i cant see that being the reason


  • #35
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    the_pen_turner wrote: »
    would it create that much pressure. a 9x 2 with even 3 gun nails on each side would hold an amzing amount of pressure. i cant see that being the reason

    That's what the insulation company said when they inspected.


  • #36
    the_pen_turner
    Registered Users Posts: 7,505 ✭✭✭the_pen_turner


    Ginger83 wrote: »
    That's what the insulation company said when they inspected.

    thats fair enough


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  • #37
    Calahonda52
    Registered Users Posts: 12,193 ✭✭✭✭Calahonda52


    Ginger83 wrote: »
    That's what the insulation company said when they inspected.

    the top 9", pressure, ****ox

    “I can’t pay my staff or mortgage with instagram likes”.



  • #38
    chooseusername
    Registered Users Posts: 3,588 ✭✭✭chooseusername


    Calahonda52 wrote: »
    the top 9", pressure, ****ox
    I'd say they didn't fancy pumping beads into a 9" high cavity not knowing the make up of the cavity.
    Op says there is bridging but not what type.
    Joists may be crossing the cavity
    Also, if pumped insulation stopped at the top of inner leaf,
    it means the builder must have closed the cavity at the top,
    Why was he surprised the top of the cavity was not pumped?


  • #39
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    Calahonda52 wrote: »
    the top 9", pressure, ****ox

    Yes that is what they said when they inspected.


  • #40
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    chooseusername wrote: »
    I'd say they didn't fancy pumping beads into a 9" high cavity not knowing the make up of the cavity.
    Op says there is bridging but not what type.
    Joists may be crossing the cavity
    Also, if pumped insulation stopped at the top of inner leaf,
    it means the builder must have closed the cavity at the top,
    Why was he surprised the top of the cavity was not pumped?

    The bridging is 9×2.
    The cavity is not closed as we made holes in the ceiling and bridging to try and find out what is wrong and you can reach in and grab the beads. We held a candle above the ceiling as a test and it blew out.


  • #41
    the_pen_turner
    Registered Users Posts: 7,505 ✭✭✭the_pen_turner


    are you saying there is wind through the ceiling joists. that definetly shouldnt be like that


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  • #42
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    the_pen_turner wrote: »
    are you saying there is wind through the ceiling joists. that definetly shouldnt be like that

    Yes and holes were drilled in the walls to measure the cavity and there is strong wind coming through holes


  • #43
    chooseusername
    Registered Users Posts: 3,588 ✭✭✭chooseusername


    Ginger83 wrote: »
    The bridging is 9×2.
    The cavity is not closed as we made holes in the ceiling and bridging to try and find out what is wrong and you can reach in and grab the beads. We held a candle above the ceiling as a test and it blew out.
    Hats off to guts who can pump a cavity to finish at the top of the cavity
    without either overflowing or underfilling, without cavity closers in place.
    (unless it was pumped before the roof deck was in place.)


  • #44
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    chooseusername wrote: »
    Hats off to guts who can pump a cavity to finish at the top of the cavity
    without either overflowing or underfilling, without cavity closers in place.
    (unless it was pumped before the roof deck was in place.)

    The roof was on when pumped, it's amazing how wrong they got it.
    It's as if someone watched a you tube video of sticking the insulation on the deck and didn't know they had to insulate the sides


  • #45
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    20201127_185532 (2).jpg

    So we opened up the double plasterboard on the ceiling and made an inspection hole in the bridging at the top of the walls.
    The pic shows the uninsulated space.


  • #46
    dathi
    Registered Users Posts: 1,386 ✭✭✭dathi


    Ginger83 wrote: »
    20201127_185532 (2).jpg

    So we opened up the double plasterboard on the ceiling and made an inspection hole in the bridging at the top of the walls.
    The pic shows the uninsulated space.

    just to be clear in the picture is 1, the concrete block the outside leaf that rises to the parapet 2, the beads the top of cavity 3, the green 9x2 is the wall plate running the length of extension with the joists running perpendicular to the wall plate on hangers and 4, the white area in the photo with 3or 4 beads on it is the topside of plasterboard ceiling. 5, on the low side of roof how does the joists finish
    6, on top of joists there is plywood and then 100m insulation plus membrane


  • #47
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    dathi wrote: »
    just to be clear in the picture is 1, the concrete block the outside leaf that rises to the parapet 2, the beads the top of cavity 3, the green 9x2 is the wall plate running the length of extension with the joists running perpendicular to the wall plate on hangers and 4, the white area in the photo with 3or 4 beads on it is the topside of plasterboard ceiling. 5, on the low side of roof how does the joists finish
    6, on top of joists there is plywood and then 100m insulation plus membrane

    1. this is the lower side
    2. correct
    3. this is bridging on inner leaf, joists also rest on inner leaf
    4. this is the top of plasterboard that's fixed to the walls
    5. joists rest on inner leaf
    6. correct


  • #48
    the_pen_turner
    Registered Users Posts: 7,505 ✭✭✭the_pen_turner


    take a pic back into the ceiling

    is the inside of the outer leaf damp


  • #49
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    the_pen_turner wrote: »
    take a pic back into the ceiling

    is the inside of the outer leaf damp

    I will get a pic soon, sorry I'm in a wheelchair.

    Yes the person that took the pic said it felt damp to touch. The white reader finish outside was stuck directly on the block. The builder claims there is a 20mm nap plaster under it but it simply is not there.


  • #50
    chooseusername
    Registered Users Posts: 3,588 ✭✭✭chooseusername


    Ginger83 wrote: »
    1. this is the lower side
    2. correct
    3. this is bridging on inner leaf, joists also rest on inner leaf
    4. this is the top of plasterboard that's fixed to the walls
    5. joists rest on inner leaf
    6. correct
    Is this what the make-up looks like?
    edit ;
    Is there a ply or osb deck missing between the insulation and the epdm?


  • #51
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    chooseusername wrote: »
    Is this what the make-up looks like?

    Wow that's it.
    The empty space is on all three sides because the bridging is in the way on the inside and opening from the outside would mean a new membrane.

    No that's the exact make up


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  • #52
    Ginger83
    Registered Users Posts: 3,415 ✭✭✭Ginger83


    the_pen_turner wrote: »
    take a pic back into the ceiling

    is the inside of the outer leaf damp

    How's this
    C16s joists.jpg


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