How to finish the joint between the old house and Extension

muganj

Hi there

As the title says I have built and extension against the original house.
Both the original house and the extension have their own rafts and the walls in the extension are kissing the original house but is not physically interlocked as i suspect there will be movement and any interlocked blocks will fail.

I am now preparing for plastering and wonder how best to finish the joint.

Can anyone recommend the process, method and materials to use.

Thank you
John

aujopimur

They should have been joined during construction using patent wall ties.

muganj

You are correct we do have Wall ties between the walls
The Insulation is also interlocked

Thanks

Calahonda52

muganj wrote: »

You are correct we do have Wall ties between the walls
The Insulation is also interlocked

Thanks

what do u mean by interlocked: the two posts suggest two contradictory situations using the same word
http://dictionary.reference.com/browse/interlock

aujopimur

The new and old wall should have been tied in during construction.

Gumbo

Something along the lines of these should have been used during construction.

http://www.ancon.co.uk/products/wall-ties-and-restraint-fixings/other-restraint-fixings/frame-cramps

Obviously using the correct fixing for the type of block used.

Bullocks

I presume the block layers used metal ties to join the old and new that we can't see now . It looks like the new wall will be plastered a bit proud of the old wall because the blocks are out almost flush with the old plaster so I would put a PVC stop bead on the new blocks and plaster into it leaving an expansion line between both walls .

muganj

That you all.

Bullocks - that is exactly what we are considering doing now

I did use wall ties between the buildings.

I was considering putting expanding foam between the walls, plastering the new wall to a stop bead but leaving a gap between the two buildings. Then after a year or so putting mastic or silicone into that gap.

What you think ?

aujopimur

kceire wrote: »

Something along the lines of these should have been used during construction.

http://www.ancon.co.uk/products/wall-ties-and-restraint-fixings/other-restraint-fixings/frame-cramps

Obviously using the correct fixing for the type of block used.

This not the correct type of fixing to tie into an existing building.

Gumbo

aujopimur wrote: »

This not the correct type of fixing to tie into an existing building.

I was more so pointing the op to the type of fixings and a particular brand / website. Posting from the phone so detailed searches is quite difficult at times.

Hence my text : obviously using the correct fixing for your type of block.

neverfinished

We used these to attach the old stone building to the extension. I can't remember what they are called but I can ask the builder.

muganj

Thank you for your input lads but can we please talk about the render at the joint
Thank you

neverfinished

Sorry. I guess I didn't pay attention to your post op. Apologies.

Bonzo Delaney

Fill masonry joint with mastic
Scud, scratch coat
Run stop bead up to within 6 mm of orignal wall
Finish coat render
Mastic 6mm joint neatly

Bullocks

Bonzo Delaney wrote: »

Fill masonry joint with mastic
Scud, scratch coat
Run stop bead up to within 6 mm of orignal wall
Finish coat render
Mastic 6mm joint neatly

Thats it in a nutshell Bonzo , if possible I'd keep the joint tighter than 6mm but it depends on how straight the old corner is

muganj

Thank you lads
I will do just that
John