Skip to content
  • Register
    • Advertisement
    If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
    Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

    Tying in External Wall Insulation on existing house to new extension

    • 15-04-2013 07:38PM
      #1
      Linto
      Registered Users, Registered Users 2 Posts: 171
      ✭✭


      Hi,
      We are externally insulating our house which was built in 9" cavity block. We were going to build a cavity wall to the latest regs for the new extension but then we're not sure how to tie that into the existing house given we are going to externally insulate the walls.
      Question is: should we consider building the new extension in 9" cavity block and then externally insulate the whole house (existing and new). That way there is no "step" in the walls, internally or externally. Its also a good u-value on the walls - right?

      Any advice?
      Tagged:


    Welcome!

    It looks like you're new here. Sign in or register to get started.
    Sign In
    Register

    Comments

    • #2
      harry21
      Registered Users, Registered Users 2 Posts: 519 harry21
      ✭✭✭


      It might not be possible to have both the inner and outer faces flush to the existing. But this situation would only arise if you were extending from the corner.... are you?


    • #3
      Linto
      Registered Users, Registered Users 2 Posts: 171 Linto
      ✭✭


      harry21 wrote: »
      It might not be possible to have both the inner and outer faces flush to the existing. But this situation would only arise if you were extending from the corner.... are you?

      Its a 2 meter extension all across the back of the house and a small extension to the front.
      Would building new wall with same 9" cavity block as existing be an option?


    • #4
      MicktheMan
      Registered Users, Registered Users 2 Posts: 2,953 MicktheMan
      ✭✭✭


      Linto wrote: »
      Question is: should we consider building the new extension in 9" cavity block and then externally insulate the whole house (existing and new). That way there is no "step" in the walls, internally or externally. Its also a good u-value on the walls - right?

      Any advice?

      I would do it with 9" block on flat and externally insulate.
      Make sure you seal the existing cavity block wall at the top to prevent warm air escaping out the top of the wall negating somewhat the ewi effectiveness.


    • #5
      Linto
      Registered Users, Registered Users 2 Posts: 171 Linto
      ✭✭


      Micktheman, is this the norm in these situations? Building with 9" cavity block seems to be somewhat frowned upon..?


    • #6
      MicktheMan
      Registered Users, Registered Users 2 Posts: 2,953 MicktheMan
      ✭✭✭


      I didn't mean 9" cavity block but rather standard 4" block (on flat)


    • Advertisement
    • #7
      Linto
      Registered Users, Registered Users 2 Posts: 171 Linto
      ✭✭


      MicktheMan wrote: »
      I didn't mean 9" cavity block but rather standard 4" block (on flat)

      Buy existing house is 9" cavity block. How else will we seemlesssly tie in EWI into extension if we don't use the same??


    • #8
      MicktheMan
      Registered Users, Registered Users 2 Posts: 2,953 MicktheMan
      ✭✭✭


      Linto wrote: »
      Buy existing house is 9" cavity block. How else will we seemlesssly tie in EWI into extension if we don't use the same??
      4" block on the flat is same size (thickness) as 9" hollow block


    Welcome!

    It looks like you're new here. Sign in or register to get started.
    Sign In
    Register
    Advertisement