Typical wall build-up at solid brick party wall

[maxdavie]

Hello, 

 

I'm just doing a bit of research on wall build ups. This is often a good place to start. 

 

We're building an office out building at the end of a long narrow garden to a terrace house. The walls separating the two properties either side of the garden are solid brick and I'm assuming party walls and not boundary walls. 

 

I want to use these brick walls if I can as the sides of the building. My assumption re the wall build up is this (though, could be wrong, hence my research):

 

• the brick wall is currently 1500mm high, so first thing is to make it higher with new brick. 
• Then, I'm wondering if I can line the interior side with dot-and-dabbed insulation-backed plasterboard. 
• I'll cap the top of the wall with some form of DPM and coping. 

 

I'm not sure how you sufficiently waterproof it though - any ideas? What's the typical build up in these scenarios ? 

 

Any thoughts / pointers massively helpful! 

 

Thanks,

 

 

 

[markc]

Do yourself a big favour here and don’t use the walls, build free standing on the inside. No grief from the neighbours that you have damaged the wall or gone over their side, no damp coming through because neighbour has heaped soil or compost against their side. No party wall agreement (discreetly put in your new foundations) 

[kandgmitchell]

These will be party fence walls at best (i.e shared between two owners) party walls separate buildings. I agree with markc, these walls will have no dpc, probably half a brick thick with piers at intervals. You'll have no control on what happens on the otherside even if it's just lack of maintenance and all the pointing falls out.

[maxdavie]

Thanks! Thought this could be the case. 

 

So, I guess timber is also prob out the question for the new inner leaf (no way to ensure its fully protected from the elements etc) 

So, a freestanding inner masonry wall? Insulation on internal side of that masonry? - not cavity between existing garden wall and new inner wall. 

 

Thanks again! 

 

 

[markc]

27 minutes ago, maxdavie said:

Thanks! Thought this could be the case. 

 

So, I guess timber is also prob out the question for the new inner leaf (no way to ensure its fully protected from the elements etc) 

So, a freestanding inner masonry wall? Insulation on internal side of that masonry? - not cavity between existing garden wall and new inner wall. 

 

Thanks again! 

 

 

Hi, you can do timber frame, build the wall (as for off site construction) horizontal, fully finish the outside (assuming you want to minimise gap to existing wall) and then raise into position, a little thought / details and planning needed as you can’t get back in the void. 
insulation in timber frame or inside new block wall, leave gap to existing wall empty

[maxdavie]

Nice - yup that's a gd shout. 

 

Thanks for advice