Neighbours extension - party/boundary wall, foundations, sound etc

RoryW

Neighbours planning 40m2 extension - I would welcome any comments from anyone for items below, thanks.

Party Wall and Boundary Wall
it would appear that between ourselves and our neighbours there are 3 walls.
A party wall (which we own jointly) and a boundary wall (which we each own individually). At present their conservatory is built up to the boundary wall.

Option 1
Leave all 3 walls "as is" and build with them in place
Comment - probably bad idea as walls will probably collapse with building work and make building work harder

Option 2
Demolish all 3 walls and they build extension on their side up to the (rebuilt) party wall and also rebuild our boundary wall on our side.

Option 3
Demolish all 3 walls. Party wall would not be rebuilt and instead their extension would be rebuilt into their half of the party wall space.

Top 3 bricks represent existing boundary/party/boundary walls to be demolished



Bottom two bricks represent building into respective halves of party wall leaving “ a very small gap” between the two walls which would then be capped or something at the top to prevent leaves, water etc from getting in but that the walls being separate by the "very small gap" they say would mean sound insulation from each other.

They said that our extension could then be built onto the new wall built on our side.

Any thoughts or comments on this ?

People have said that we should not let the house beside us to encroach on the party wall. If they were to build into the party wall what pros/cons would it have for us and our extension ?

Would sound insulation be ok for us with this proposal and also any water/damp issues from the "slight" gap ? Some people have said you need to leave a two feet gap between the two extensions for sound insulation and damp issues. Is that correct ?

Is there a specification we would need for the wall to be able to build our extension on to it.

Foundations
They suggested pouring foundations across into our side (not sure how far) and build walls on top.
Alternatively foundations are only done on their side but then this would mean foundations would need to be poured separatey on our side for our wall and extension to have foundations. They mentioned this is slightly more complicated but they had no problem doing that if that is what we wanted.

People have said not to allow them to pour foundations on our side. What are the pros/cons of this or what they propose ?

Comment
Whilst our plans are not finalised (or started !), if we end up going with an extension across to boundary wall, will building of our extension be complicated by what they are doing or proposing ?

I would be very grateful for any comments on the above

Gumbo

My opinion is always work with your neighbors here as you may need to extend in the future yourself.

I would demolish all walls. Pour a properly designed foundation and structural wall capable of taking two storeys both sides in the middle of the boundary line. I would finish off the top with a parapet wall and capping detail.

Get all these details and a drawing done by an engineer at the neighbors expense (it will benefit you later on).

That way your neighbor can build on their side keeping all finishes on their side including drainage. Then when it comes to a time that you want to build, you can simply connect to the new wall as its already in place.

I would sand /cement render it, create a cavity with 150mm insulation and then build an inner leaf for the extension along with any air tightness detail of required.

Calahonda52

Re the structural aspects, am with kc here as well as where it should be built.
There can be no question of them building up to the party wall line but not into your property because if so, the wall is no longer a party wall.
Also with working with your neighbour: best idea but doesn't always work.

Re the:
Some people say and People have said:
You all need to read
http://www.irishstatutebook.ie/eli/2009/act/27/section/43/enacted/en/html

and get with the program: its no longer a question of " not allow": that day is gone since the introduction of the "works order"
They will cost ur neighbour about 3,000 if you can't agree.
I find it best if you can agree, as already said by kc: the approach should be, how can u benefit from this

RoryW

Thanks KC

kceire wrote: »

My opinion is always work with your neighbors here as you may need to extend in the future yourself.

Agreed always go to work with neighbours than fall out with them

kceire wrote: »

Pour a properly designed foundation.

Would you allow them to put foundation on our side for the new walls to be built on ?

kceire wrote: »

structural wall capable of taking two storeys both sides in the middle of the boundary line.

to use my brick analogy below, is this the bottom of picture where both sides build extension walls into the party line area and not rebuild the party wall

kceire wrote: »

I would finish off the top with a parapet wall and capping detail.

they plan a flat roof, need to figure out what they means with a parapet wall

Gumbo

RoryW wrote: »

Thanks KC



Agreed always go to work with neighbours than fall out with them



Would you allow them to put foundation on our side for the new walls to be built on ?



to use my brick analogy below, is this the bottom of picture where both sides build extension walls into the party line area and not rebuild the party wall



they plan a flat roof, need to figure out what they means with a parapet wall

Yes. Foundations will have to be centered on the boundary line so will pass out 500mm onto your side.

Brick analogy : one wall. Probably 215mm wide rendered on your side will be the outcome.

Flat roof and parapet wall goes hand in hand.

Calahonda52

OP:
Re this
Would you allow them to put foundation on our side for the new walls to be built on ?
in the context of the link I posted,

how do you propose to "dis-allow" them if you are so minded.

Simple wall foundation design as in the TGD's,
http://www.environ.ie/housing/building-standards/tgd-part-d-materials-and-workmanship/technical-guidance-documents
is that the foundation needs to be 3 times the wall width, with wall centred on the foundation and, in this case to protect your constitutional pretty rights, on the party line.
Unless you can prove otherwise, for example that it is not safe/practical to do this on your side, then the works order will allow them do this.

It is good practice also to photograph the existing on your side and print off hard copies and agree this with the neighbour.
This is done especially if there are existing shrubs, beds etc that need to be re-instated.

The strict legal provision here is that the photo should have a physical negative, as the digital ones can be altered, however only in one case have I seen this insisted on: however you do need hard copy with time and date printed on front, and agreed with neighbour, before any work starts.

RoryW

thanks for the replies, appreciated