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Removing parts of garage roof - bad idea?

Discussion in 'Roofing and Guttering' started by Temmy, 17 Apr 2020.

  1. Temmy

    Temmy

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    Hello folks,

    I'm looking at our garage. It used to be flat roofed and then the previous owner of our house installed a taller pitched roof structure on top.

    [​IMG]

    [​IMG]

    What I'd like to do is open up into that space a bit more by removing the planks running the length of the old roof - NOT touching the cross beams. I'd totally leave those in place.

    Do you think that's a no go of an idea?


    Stay well and safe,
    P
     
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  3. Alastairreid

    Alastairreid

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    The old deck boards are serving no purpose now and are quite safe to remove.
    the joists are probably redundant as well but cant see how the new roof is tied in so may still be needed.
     
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  4. Temmy

    Temmy

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    Thanks for the reply @Alastairreid. My (very basic and limited) understanding is joists aren't just there for the roof, but would also be there to lend support keeping the side walls stable. Have I got that wrong?
     
  5. Tigercubrider

    Tigercubrider

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    It looks to me as if the roof extension was plonked onto the existing structure, by building a timber box around the perimeter then adding an apex roof.

    I expect that most of the centre of the old deck could safely go, but I'd closely examine how the new wooden box fits into the scheme of things?
     
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  6. Notch7

    Notch7

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    its a bit hard to know -there is nothing obvious providing lateral support to the timber frame dwarf walls that were used to raise the height.

    there are new ties which connect the common rafters and they stop the roof spreading. Normally those ties are joists which sit directly on top of the wall plate. In your case the lower set of joists are dong that. Removing them relies on the rafter ties doing that job, but the are higher up and any movement in the dwarf stud walls will allow the wall to move.
     
  7. Temmy

    Temmy

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    You're absolutely right. It was very much plonked on top. Couple of new photos, but I can't see any connection of the wooden box to the decking / boards of the old roof.

    [​IMG]

    [​IMG]
     
  8. Alastairreid

    Alastairreid

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    In this case they were to lay the deck boards on.
    On a pitched roof they are to stop the roof spreading.
    They wont be creating structural stability.
     
  9. noseall

    noseall

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    The short upright extender studs prob's just needed some ply fixing to them to prevent racking - which they have done externally.
    I'd be more concerned with how they have cut the rafter onto the wall plate. It looks like it is mostly in shear.o_O
     
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  11. mattylad

    mattylad

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    Why do you want to remove them? What are you hoping to achieve?
    I ask this because you will be losing a large space where you can store the crap that we humans like to keep "just in case"..... :)
     
  12. Temmy

    Temmy

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    Total fair question @mattylad; I've got some equipment I want to put in there which is a bit taller than the original roof, but would fit in between the joists. I don't want to completely remove the storage space but it's much much deeper than I'll ever need.
     
  13. JohnD

    JohnD

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    A pitched roof is (normally) built in triangular sections. Cutting or removing any of the arms of the triangle will make it collapse. In the case of the "loft floor" joists, cutting or removing them usually pushes the walls apart and makes the building fall down. This is more common than you might think.

    The "floorboards" on top of the joists add stiffness but can be removed without collapse.
     
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  14. Temmy

    Temmy

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    Hey @JohnD thanks for the reply. That was my understanding as well so I won't be touching those. Quite happy not having a wall come down on me.
     
  15. Alastairreid

    Alastairreid

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    They were originally put in for a flat roof not triangulating a pitched roof...in this case unless the roof above is attached to them some way they are serving no purpose.
     
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  16. Temmy

    Temmy

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    New question folks (and I really appreciate all your input and advice so far!)

    How would you go about cutting out & removing the boards? I can't just saw in from the open edge because I don't want to touch the joists at all.

    [​IMG]

    There are 3 layers of material and from what I can tell the top two are HUGE sheets (so offer no easy way to break up)

    [​IMG]
     
  17. noseall

    noseall

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    Recip saw - Bosch bow-saw type blade - rip it down the middle. Prop either side of the cut.(y)
     
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