Any idea why my wall has bits of bricks set in black mortar? Im puzzled!

[Gary1111]

Hi, when chipping loose plaster off my 1st floor exterior wall, I found an area near the top with small pieces of brick and stone, a bit loose set in black mortar.

When I removed those, I found another coarse of full size bricks that are set back from the rest of the wall.

It's on the top floor.

I'm wondering what is best to do with this, is it something I should worry about?
Or possibly just remove the loose partial bricks and stones and cement over where they were to bring that part of the wall back out?

I am planning to dot and dab moisture resistant plasterboard to try and make it straighter and tile on top of that.

Thanks in advance.

 

[paulc]

I am planning to dot and dab moisture resistant plasterboard to try and make it straighter and tile on top of that.

If you are tiling, I'd suggest using an insulating backer board like Marmox rather than plasterboard. Strongly recommend using mechanical fixings in addition to adhesive then the whole lot is unlikely to fall off the wall.

 

[Gary1111]

Thanks, but has anyone got any idea why it has been built this way please?
As far as I can work out its like this.

 

[stuart45]

It could be the roof had spread a bit, and the top courses were rebuilt closing the cavity.

 

[mardinor]

Is your house old enough to previously have been thatched? And is the exterior rendered? Usually the roof angle is steeper on thatch, meaning the walls get extended up slightly when later tiled. There was a house in my village that had visible bricks on the exterior above stone, just like your sketch.

 

[Gary1111]

Is your house old enough to previously have been thatched? And is the exterior rendered? Usually the roof angle is steeper on thatch, meaning the walls get extended up slightly when later tiled. There was a house in my village that had visible bricks on the exterior above stone, just like your sketch.

Thanks but no it's not that old

 

[Gary1111]

It could be the roof had spread a bit, and the top courses were rebuilt closing the cavity.

Thanks that makes sense, but it must have been done soon after the house was built as it's done with black ash mortar?

 

[Gary1111]

Should I remove the part bricks and fill the space with normal mortar?
Or might that cause cracking?

 

[Gary1111]

There are actually some large gaps on the edge of this wall also, where the outer wall is set at a right angle

 

[Gary1111]

Does that support the roof spread theory?

 

[stuart45]

It does look like there's been a fair bit of movement in the wall.

 

[stuart45]

Should I remove the part bricks and fill the space with normal mortar?
Or might that cause cracking?

Thicker render is more likely to crack, than when it's broken up with small pieces of masonry.

 

[Gary1111]

Thicker render is more likely to crack, than when it's broken up with small pieces of masonry.

Thanks for your help Stuart

 

[Feltwell]

If you are tiling, I'd suggest using an insulating backer board like Marmox rather than plasterboard. Strongly recommend using mechanical fixings in addition to adhesive then the whole lot is unlikely to fall off the wall.

This old thread has a bit about Abacus Elements board. Marvellous stuff.

https://www.periodproperty.co.uk/forum/threads/teeny-tiny-bathroom-saga.17602/

 

[Gary1111]

This old thread has a bit about Abacus Elements board. Marvellous stuff.

https://www.periodproperty.co.uk/forum/threads/teeny-tiny-bathroom-saga.17602/

Thanks I've just been looking at those as they do an adhesive that you don't need to use mechanical fixings with.
Seems expensive though

 

[jamest]

Wedi board is almost exactly the same (as far as it's possible to tell) as the Abacus board, it may be a bit cheaper. I got mine from Topps, where it's about the same price as Hardie Backer board - not the cheapest place, but they tend to have loads in stock and I can drive there in 10 minutes, saves on delivery charges.

 

[Stevers]

My previous home in Yeovil (built 1913) was an early example of cavity wall construction in the area mostly using Bridgwater bricks. At the top of the internal wall upstairs were a few rows of brick slips that were pretty loosely bedded in a black ash mortar. In our case the builders had closed the cavity at this point with a row of stone ashlar blocks and the slip bricks made up the gap to the plaster. If I remember correctly the roof sat on a timber plate on the back edge of the ashlar blocks. Your photo and drawing look to be a more rustic version of this.

 

[stuart45]

That's quite an unusual method of closing the cavity. Normally you just ran a course of headers to close it and then bedded the plate on top.

 

[Gary1111]

That's quite an unusual method of closing the cavity. Normally you just ran a course of headers to close it and then bedded the plate on top.

Thanks Stuart, is there any way I can check ?

 

[stuart45]

If you hack off a bit more plaster up to the ceiling, you'll see the plate and if it's moved out a bit.