Double course party wall

[mpbrock]

Hi

Between our house and neighbours house is a double course party wall, both propertys have a flat roof on at the moment but i'm doing the plans for converting our flat roof to a pitched one (with dormer).. however i'm unsure what to do with the party wall... obviously it needs raising on my side to seal off the side of the pitched roof but was thinking neighbours side can remain at the same height it is currently... but if thats the case how do you seal off the cavity between them? do you just put masonary over the cavity and then flash over the top?

Thanks in advance

Matt

 

[freddiemercurystwin]

Is this a cavity wall? If so what width is the cavity?

In anycase if your neighbour agrees, it would be better just to take both skins up. How are you gonna keep the rain out with just 1 skin of masonry? What about insulation? Are BC involved?

 

[mpbrock]

Hi

Yup B/C involved (not submitted plans to them yet).

I believe its a cavity wall... looking down from the loft we've got two adjacent walls (one on my side holding up ridge beam and one on neighbours side holding up his ridge beam). Although you've just made me realise something....

We're a row of terraces (all with flat roofed extensions - which im looking to pitch) and next to my neighbour they've done the same thing as what i'm proposing and brought the party wall up higher - however looking at it the extended party wall is wider above the original house than it is on the extension making me think that the original house has a double course party wall and the extension only has a single course party wall... does this make sense?

Have mentioned the plan to neighbour and he seems fine with it.

Thanks again

Matt.

 

[^woody^]

A wall is a wall, so it doesn't matter whether you take both skins up or just one half. In either case you would just make the neighbours roof good and form a felt upstand and flashing detail where the roof meets the wall

If you do this in single skin, then you need to design it so it is weatherproof, fireproof, insulated, and stable. None of these will be an issue with a cavity wall