Connecting up to an old wall

[trevorbayliss]

My extension will be following the line of the original extension bit on the back of the house.

However, this wall is quite a bit out of level, so i was wondering what happens here when i join into it. I am using walk starter kits, but around the current gutter level i will be building the wall up higher and so running into the original courses.

Do make my wall to follow this walls level or do i try get my new wall level while blending in with the older wall level ?

 

[^woody^]

Level or plumb

Anyway, search for pilbury's recent post on this very same thing .... plumb.

 

[pilsbury]

Exactly the same situation for me....... I spent ages procrastinating and deliberating what I should do and seem to have chosen the wrong option.... for me at least.

I am building a blockwork extension where the back wall is a continuation of the original brick wall. Both sections will be rendered after. My original brick wall leans out at the top like yours does. I chose the route of building my new block wall plumb. At the bottom both walls are flush with eachother.... at the top, the new block wall sits nearly 2cm back from the original brick wall.

This has caused me an issue with the rendering - when rendering 2 different walls (old and new) there is likely to be some settlement movement which will crack the render at the join. A thin flexible plastic movement strip is usually place over this join - kind of like a double sided stop bead to allow for this slight movement without cracking the render and looking crap. This works fine if both walls are flush with eachother...... you can now see my problem.

In true bodger fashion I intend to whack on extra render to the offending recessed wall to build it up to nearly the same, then bang on 2 stop beads and silicon down the middle. If that looks ******, stick a drainpipe in front!

 

[trevorbayliss]

Well you have an easier option of rendering and so covering up.

I need to continue the wall in the correct brick courses. I am not knocking out bricks and have gone for the easier option of a wall starter kit. So i will have a 2.3m long join, but i can live with this. I wasn't planning on putting in a silicon gap here. Maybe i will need to. But i am going to be building higher than the current wall as this is set at a 35 degree pitch and i am fitting a flatter roof. So i will be running in some courses higher up and this area will join in properly as you would get with toothing.

So i think what i have to do is make my new corner level and then blend in this level wall with the older wall which is out.

I am doing full fill insulation so i suppose the 100mm gap will get compressed a little.

 

[trevorbayliss]

And yes i meant PLUMB

 

[^woody^]

That's a massive amount out-of-plumb in the length of a level. Are you sure that the level is not out?

 

[trevorbayliss]

It might possibly be now i think about it. I have a longer straight edge and 2 other levels so will check tomorrow.

 

[trevorbayliss]

I have checked this morning and the wall is out of plumb in different ways it seems.

I have used a different level and the same reading happens. When i held the level and straight edge a little further back on the wall it was level, but the brick work at the top was not leaning out, but inwards. I put a piece of cardboard to show the gap.

I think i can match the walls in, but is it difficult ? Will it matter if my cavity gap narrows in this area of the join ? It is going to be full fill 100mm.

 

[^woody^]

Build the outer corner plumb as normal, and then just run the brickwork into the existing. It wont matter and it wont be noticable.

 

[trevorbayliss]

ok, thanks, gives me a bit of confidence.