Common boundary wall thickness?

Discussion in 'Development' started by kennyboi, 16th Jun, 2022.

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  1. kennyboi

    kennyboi Well-Known Member

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    Hi,

    I am intending to build a garage and attached granny flat along the rear boundary behind a house on a duplex site (15m wide) in Sydney inner west. I am thinking of splitting garage and GF halfway in case I need to split them later when building a duplex to avoid knocking it down. I wonder if the common boundary wall can be thinner than 250?

    Thanks!
     
  2. Stoffo

    Stoffo Well-Known Member

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    Haven't done this, but my understanding it is the fire rating that is important (Not the wall thickness).
     
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  3. Ace in the Hole

    Ace in the Hole Well-Known Member

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    Pretty sure you can’t have a duplex and a granny flat as that would be 3 dwellings.
     
  4. kennyboi

    kennyboi Well-Known Member

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    The granny flat half would need to be backward convertible back to "garage" so it function as a storage shed if I had to. Still better than knocking it down I hope?
     
  5. Tufan Chakir

    Tufan Chakir Well-Known Member

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    Fire rating of the future boundary is the first answer - Hardie's, or similar suppliers have products that can reduce the wall thickness. But I tend to go with two separate, fire rated walls with the boundary in the middle. That way if a future subdivision occurs the walls can each be on their own title
     
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  6. Scott No Mates

    Scott No Mates Well-Known Member

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    You also need to consider noise transmission and separation. Dual wall systems may meet the standards more easily than a single mass structure.
     
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  7. kennyboi

    kennyboi Well-Known Member

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    Does anyone know if there is a max. area on outbuildings for a duplex?
     
  8. Scott No Mates

    Scott No Mates Well-Known Member

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    Regulated via site coverage allowed.
     
  9. kennyboi

    kennyboi Well-Known Member

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    Do you mean FSR overall?
     
  10. Scott No Mates

    Scott No Mates Well-Known Member

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    Depends on the standard used in the DCP/LEP but similar principle.
     
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  11. lakersfan23

    lakersfan23 Well-Known Member

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    Agree with Scott No Mates. Your architect will be able to advise on the thickness potentially 220 as well subject to the applicable DCP/LEP.

    Another way you can check is to see duplexes built in your suburb via the IWC portal ideally on the same street. Hope this helps.

    Which suburb in the inner west ?

    https://www.innerwest.nsw.gov.au/ArticleDocuments/32360/How to view a determined DA .pdf.aspx
     
  12. kennyboi

    kennyboi Well-Known Member

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    lakersfan23 likes this.

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