Insullation on a single skin extension

Discussion in 'UK DIY' started by JGralton@gmail.com, Aug 3, 2006.

  1. Guest

    Hi all,

    I have recently moved in to a house with a single skin extension. After
    a cold winter I want to add some insulation to the extension wall on
    the inside. After some research I decided to use a thermo board (e.g.
    Fermacall - other recommendation welcome). At first I was going to use
    a dot and dab technique to fix the boards to the walls, I then read
    that this might not be the best approach especially as I want to hang a
    radiator off the board and as I have not used dot and dab before it may
    be a little more difficult.

    So now I am looking at putting a wood batten framework on the wall and
    attaching the thermo board to the battens. I have looked around but
    can't find the answer to the following questions. Any comment/help is
    much appreciated:

    1. What size battens should I be using to fix the thermo board to?

    2. Is it best to attach the battens to the wall with screws and how
    much longer should the screws be than the batten?

    3. I plan on using a 30 or 40mm thermo board, how long should the nails
    be, which are used to attach the thermo board to the battens, or should
    I be using screws here?

    4. I was to be able to decorate directly on to the thermo board without
    needing to skim any recommendations on a board manufacturer I should
    use? Or is this a bad idea and is there another type of board I should
    use and then plaster/skim?


    Thank you very much,

    Jimbo
     
    , Aug 3, 2006
    #1
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  2. TMC Guest

    <> wrote in message
    news:...
    > Hi all,
    >
    > I have recently moved in to a house with a single skin extension. After
    > a cold winter I want to add some insulation to the extension wall on
    > the inside. After some research I decided to use a thermo board (e.g.
    > Fermacall - other recommendation welcome). At first I was going to use
    > a dot and dab technique to fix the boards to the walls, I then read
    > that this might not be the best approach especially as I want to hang a
    > radiator off the board and as I have not used dot and dab before it may
    > be a little more difficult.
    >
    > So now I am looking at putting a wood batten framework on the wall and
    > attaching the thermo board to the battens. I have looked around but
    > can't find the answer to the following questions. Any comment/help is
    > much appreciated:
    >
    > 1. What size battens should I be using to fix the thermo board to?
    >
    > 2. Is it best to attach the battens to the wall with screws and how
    > much longer should the screws be than the batten?
    >
    > 3. I plan on using a 30 or 40mm thermo board, how long should the nails
    > be, which are used to attach the thermo board to the battens, or should
    > I be using screws here?
    >
    > 4. I was to be able to decorate directly on to the thermo board without
    > needing to skim any recommendations on a board manufacturer I should
    > use? Or is this a bad idea and is there another type of board I should
    > use and then plaster/skim?
    >
    >
    > Thank you very much,
    >
    > Jimbo
    >


    If you are fixing battens to the outside wall then you would need a
    waterproof barrier between them and the single skin wall

    The thickness of the battens may be determined by the type and thickness of
    insulation that you put between them
    but also by how much you are reducing the space in the room

    When I have done this sort of job in the past I have done the following

    Construct a 4 x 2 frame spaced off of the existing wall with a waterproof
    membrane on the existing wall side
    Insulate within the frame with rockwool or polystyrene and face with
    plasterboard

    Not sure if it meets current standards however

    Tony
     
    TMC, Aug 3, 2006
    #2
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  3. Guest


    > If you are fixing battens to the outside wall then you would need a
    > waterproof barrier between them and the single skin wall

    Hi Tony,

    I wondered if I would need this. There is no barrier there at the
    moment at none that I am aware of yet we have had no problem with damp
    or anything. Will this become a problem when I add the insulation and
    that is why I will now need a waterproof membrane?

    > The thickness of the battens may be determined by the type and thickness of
    > insulation that you put between them
    > but also by how much you are reducing the space in the room


    Well that is part of the problem I want to reduce the size of the room
    by as little as possible while still achieving the best insulation.
    That's way I was looking down the thermo board route. I wondered if 2x1
    frame packed with rockwool and then 30mm thermo board would be ok.
    Would your suggestion offer the same insulation (need to reduce my gas
    bill - lol)


    Do you have any idea on the length or screws/nails I should be using?

    Cheers,

    James
     
    , Aug 3, 2006
    #3
  4. TMC Guest

    <> wrote in message
    news:...
    >
    >> If you are fixing battens to the outside wall then you would need a
    >> waterproof barrier between them and the single skin wall

    > Hi Tony,
    >
    > I wondered if I would need this. There is no barrier there at the
    > moment at none that I am aware of yet we have had no problem with damp
    > or anything. Will this become a problem when I add the insulation and
    > that is why I will now need a waterproof membrane?
    >
    >> The thickness of the battens may be determined by the type and thickness
    >> of
    >> insulation that you put between them
    >> but also by how much you are reducing the space in the room

    >
    > Well that is part of the problem I want to reduce the size of the room
    > by as little as possible while still achieving the best insulation.
    > That's way I was looking down the thermo board route. I wondered if 2x1
    > frame packed with rockwool and then 30mm thermo board would be ok.
    > Would your suggestion offer the same insulation (need to reduce my gas
    > bill - lol)
    >
    >
    > Do you have any idea on the length or screws/nails I should be using?
    >
    > Cheers,
    >
    > James
    >


    I guess that the wall has presently nothing on the inside of it i.e. is just
    bare brick or block

    Any dampness penetrating the brickwork would dry out from the inside

    If you were to seal this wall as you originally suggested then this damp
    would be trapped in the wall & penetrate the board and decorations

    When cavity wall houses are built a lot of care should go into keeping the
    outer skin and inner wall as separate as possible e.g by avoiding mortar
    bridges on wall ties and having moisture/thermal barriers where there are
    windows and doors which bridge the cavity.

    Where I have seen bungalows built with wood frame inner and blockwork outer
    walls they were insulated in the way I described

    In terms of increasing insulation and reducing gas bills the thicker the
    better so a 2 inch wall with rockwool is better than nothing but a 4 inch
    wall is better that a 2 inch

    As to nail length I would use 65mm galvanised nails as the next size down
    50mm does not for me have enough into the batten, others may disagree

    If you are going to fix 2 inch battens directly to the outer wall then I
    would use http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=01127&id=17286

    Tony
     
    TMC, Aug 3, 2006
    #4
  5. TMC Guest

    "TMC" <> wrote in message
    news:...
    >
    > <> wrote in message
    > news:...
    >>
    >>> If you are fixing battens to the outside wall then you would need a
    >>> waterproof barrier between them and the single skin wall

    >> Hi Tony,
    >>
    >> I wondered if I would need this. There is no barrier there at the
    >> moment at none that I am aware of yet we have had no problem with damp
    >> or anything. Will this become a problem when I add the insulation and
    >> that is why I will now need a waterproof membrane?
    >>
    >>> The thickness of the battens may be determined by the type and thickness
    >>> of
    >>> insulation that you put between them
    >>> but also by how much you are reducing the space in the room

    >>
    >> Well that is part of the problem I want to reduce the size of the room
    >> by as little as possible while still achieving the best insulation.
    >> That's way I was looking down the thermo board route. I wondered if 2x1
    >> frame packed with rockwool and then 30mm thermo board would be ok.
    >> Would your suggestion offer the same insulation (need to reduce my gas
    >> bill - lol)
    >>
    >>

    Just picked up on your suggested batten size

    I would not use 2x1 batten need to be at least 2x2 especially if as you
    suggested earlier you want to hang a radiator off of it

    Tony

    Tony
     
    TMC, Aug 3, 2006
    #5
  6. Guy King Guest

    The message <>
    from contains these words:

    > I have recently moved in to a house with a single skin extension. After
    > a cold winter I want to add some insulation to the extension wall on
    > the inside.


    You might also consider adding cladding to the outside. uPVC cladding on
    cross-battens with rockwool behind would improve things quite a bit
    provided you make the framing so there's no howling gale round the back
    of it.

    --
    Skipweasel
    Pay no attention to that man behind the curtain.
     
    Guy King, Aug 3, 2006
    #6
  7. TMC wrote:
    > "TMC" <> wrote in message
    > news:...
    >> <> wrote in message
    >> news:...
    >>>> If you are fixing battens to the outside wall then you would need a
    >>>> waterproof barrier between them and the single skin wall
    >>> Hi Tony,
    >>>
    >>> I wondered if I would need this. There is no barrier there at the
    >>> moment at none that I am aware of yet we have had no problem with damp
    >>> or anything. Will this become a problem when I add the insulation and
    >>> that is why I will now need a waterproof membrane?
    >>>
    >>>> The thickness of the battens may be determined by the type and thickness
    >>>> of
    >>>> insulation that you put between them
    >>>> but also by how much you are reducing the space in the room
    >>> Well that is part of the problem I want to reduce the size of the room
    >>> by as little as possible while still achieving the best insulation.
    >>> That's way I was looking down the thermo board route. I wondered if 2x1
    >>> frame packed with rockwool and then 30mm thermo board would be ok.
    >>> Would your suggestion offer the same insulation (need to reduce my gas
    >>> bill - lol)
    >>>
    >>>

    > Just picked up on your suggested batten size
    >
    > I would not use 2x1 batten need to be at least 2x2 especially if as you
    > suggested earlier you want to hang a radiator off of it
    >
    > Tony
    >
    > Tony
    >
    >
    >

    Agreed. My old place had a converted garage as a room..they used about
    2x2 and rockwool over a plastic membrane. It was pretty warm and cosy.

    Made rigging cable easy too. Holes and coathangers could thread most of
    what you wanted behind the plasterboard..
     
    The Natural Philosopher, Aug 3, 2006
    #7
  8. Lobster Guest

    The Natural Philosopher wrote:
    > TMC wrote:
    >> "TMC" <> wrote in message
    >> news:...
    >>> <> wrote in message
    >>> news:...
    >>>>> If you are fixing battens to the outside wall then you would need a
    >>>>> waterproof barrier between them and the single skin wall
    >>>> Hi Tony,
    >>>>
    >>>> I wondered if I would need this. There is no barrier there at the
    >>>> moment at none that I am aware of yet we have had no problem with damp
    >>>> or anything. Will this become a problem when I add the insulation and
    >>>> that is why I will now need a waterproof membrane?
    >>>>
    >>>>> The thickness of the battens may be determined by the type and
    >>>>> thickness of
    >>>>> insulation that you put between them
    >>>>> but also by how much you are reducing the space in the room
    >>>> Well that is part of the problem I want to reduce the size of the room
    >>>> by as little as possible while still achieving the best insulation.
    >>>> That's way I was looking down the thermo board route. I wondered if 2x1
    >>>> frame packed with rockwool and then 30mm thermo board would be ok.
    >>>> Would your suggestion offer the same insulation (need to reduce my gas
    >>>> bill - lol)
    >>>>
    >>>>

    >> Just picked up on your suggested batten size
    >>
    >> I would not use 2x1 batten need to be at least 2x2 especially if as
    >> you suggested earlier you want to hang a radiator off of it


    >>

    > Agreed. My old place had a converted garage as a room..they used about
    > 2x2 and rockwool over a plastic membrane. It was pretty warm and cosy.
    >
    > Made rigging cable easy too. Holes and coathangers could thread most of
    > what you wanted behind the plasterboard..


    I'm doing the same job at the moment, and using 2"x2" to make a stud
    frame 1" away from the brick wall; am putting 2" slabs of Kingspan solid
    foam board within the frame, then will cover the lot with
    insulation-backed plasterboard. Kingspan is much more efficient than
    Rockwool for a given thickness, and easier to position within studwork
    IMHO. Obtain cheap but perectly adequate 'seconds' quality from
    www.secondsandco.co.uk

    David
     
    Lobster, Aug 3, 2006
    #8
  9. Guest

    Thanks for everyones help here it is very much appreciated. A couple
    more questions:

    How far in to the wall should I screw the 2x2 battens (i.e. how long
    should the nails be)

    Also what is the reason for putting the battens an inch away from the
    wall?

    Cheers,

    James
    Lobster wrote:
    > The Natural Philosopher wrote:
    > > TMC wrote:
    > >> "TMC" <> wrote in message
    > >> news:...
    > >>> <> wrote in message
    > >>> news:...
    > >>>>> If you are fixing battens to the outside wall then you would need a
    > >>>>> waterproof barrier between them and the single skin wall
    > >>>> Hi Tony,
    > >>>>
    > >>>> I wondered if I would need this. There is no barrier there at the
    > >>>> moment at none that I am aware of yet we have had no problem with damp
    > >>>> or anything. Will this become a problem when I add the insulation and
    > >>>> that is why I will now need a waterproof membrane?
    > >>>>
    > >>>>> The thickness of the battens may be determined by the type and
    > >>>>> thickness of
    > >>>>> insulation that you put between them
    > >>>>> but also by how much you are reducing the space in the room
    > >>>> Well that is part of the problem I want to reduce the size of the room
    > >>>> by as little as possible while still achieving the best insulation.
    > >>>> That's way I was looking down the thermo board route. I wondered if 2x1
    > >>>> frame packed with rockwool and then 30mm thermo board would be ok.
    > >>>> Would your suggestion offer the same insulation (need to reduce my gas
    > >>>> bill - lol)
    > >>>>
    > >>>>
    > >> Just picked up on your suggested batten size
    > >>
    > >> I would not use 2x1 batten need to be at least 2x2 especially if as
    > >> you suggested earlier you want to hang a radiator off of it

    >
    > >>

    > > Agreed. My old place had a converted garage as a room..they used about
    > > 2x2 and rockwool over a plastic membrane. It was pretty warm and cosy.
    > >
    > > Made rigging cable easy too. Holes and coathangers could thread most of
    > > what you wanted behind the plasterboard..

    >
    > I'm doing the same job at the moment, and using 2"x2" to make a stud
    > frame 1" away from the brick wall; am putting 2" slabs of Kingspan solid
    > foam board within the frame, then will cover the lot with
    > insulation-backed plasterboard. Kingspan is much more efficient than
    > Rockwool for a given thickness, and easier to position within studwork
    > IMHO. Obtain cheap but perectly adequate 'seconds' quality from
    > www.secondsandco.co.uk
    >
    > David
     
    , Aug 4, 2006
    #9
  10. wrote:
    > Thanks for everyones help here it is very much appreciated. A couple
    > more questions:
    >
    > How far in to the wall should I screw the 2x2 battens (i.e. how long
    > should the nails be)


    As far as you can for good connections. I would screw rather thannail.
    >
    > Also what is the reason for putting the battens an inch away from the
    > wall?
    >


    I assue we are talking dry lining rahther than exterior?


    I suppose someone is worried about damp or condensation in the insulated
    wall rotting the studs.

    Mostly I have seen a polythene layer applied to the bricks and the studs
    screwed straight through it. However this puts the vapour barrier at
    the cold side of the insulation.

    The other way is to use a foil backed plasterboard and hope that the
    natural breathing of the bricks keeps the outer skin dry. The foil will
    prevent internal moisture causing condensation.


    It pays to remember that although the regulations are very fine and if
    followed correctly lead to structures hat should last 200 years or more,
    much extension work should be considered as probably only in the range
    of 15-60 years. A little damp and rot will take that long to eat through
    a bit of timber.


    >
     
    The Natural Philosopher, Aug 5, 2006
    #10
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