Tony Tray Airtightness

[Johnny Jekyll]

We have 253mm posi-joists for our build, which will sit on the walls and therefore protrude above into the next row of blocks, so the next row of blocks will need to be cut/notched around them. We would like to use the Tony Tray technique, but to avoid trying to fiddle the membrane around the posi-joists and the notched blockwork, can anyone see a problem with bringing the membrane back in on the next row of blocks above? An overall flaw or perhaps a wall tie problem? See attached photos, hope it makes sense. Thanks.

Edited April 11, 2021 by Johnny Jekyll

[tonyshouse]

tony likes it, which courses will the wall ties be in? 
 

where the inside if the tray flaps over the blockwork I pin or staple EML over it before wet plastering this works well at ceiling level or behind the skirting, slightly more concerned about a slip plane one course up and a crack developing. Escape route is to turn the tray 50mm down and fix 150 wide EML over it, 50mm of hermetically sealed to blocks above and below and anti cracking over it. 

[Johnny Jekyll]

19 minutes ago, tonyshouse said:

tony likes it, which courses will the wall ties be in? 
 

where the inside if the tray flaps over the blockwork I pin or staple EML over it before wet plastering this works well at ceiling level or behind the skirting, slightly more concerned about a slip plane one course up and a crack developing. Escape route is to turn the tray 50mm down and fix 150 wide EML over it, 50mm of hermetically sealed to blocks above and below and anti cracking over it. 

 

Excellent thanks Tony. So the EML will hold it in place if using wet plaster.

Haven't got the locations of wall ties yet.

We may use an airtight membrane (e.g. Gerband or Intello) instead of parge or wet plaster, that's probably another question which I'd like opinions on.

Thanks.

 

 

[Oz07]

Why not introduce 3 course of coursing brick above joists and brick it back in 300mm from bottom of joist, ie around top of chipboard level. 

[tonyshouse]

Thermal bridging, or use bricks with same U-value, different materials = potential cracking 

 

Ptrsumr tray goes over bricks 

[Oz07]

I meant concrete bricks/brickette/clunkers. 

[Johnny Jekyll]

Thanks guys

[CC45]

concrete commons

[tonyshouse]

= disastrous thermal bridging and cracking due to different materials in wall, plus nightmare to cut over top of floor beams

[joe90]

Have you built the wall yet?,

what blocks are you using for the inner skin?

[Johnny Jekyll]

Have updated my drawing further to Tony's advice.

joe90 both inner and outer skin are medium dense blocks.

Any opinions on parge coat vs wet plaster vs membrane for air tightness? 

[joe90]

@Johnny Jekyll reason for asking type of blocks, aerated blocks can be cut by hand saw, scratch that one. ?

Edited April 13, 2021 by joe90

[tonyshouse]

I turn the tray down or up 50 mm cover the edge with EML half on the blocks, half on the membrane and wet plaster to give hermetic seal. 

[Johnny Jekyll]

On 13/04/2021 at 18:36, tonyshouse said:

I turn the tray down or up 50 mm cover the edge with EML half on the blocks, half on the membrane and wet plaster to give hermetic seal. 

 

May I ask a question. Can you recommend a breathable membrane to use for the Tony Tray? A  link to the product would be ideal if possible thanks.  

[tonyshouse]

I sent PM 

[ruggers]

On 11/04/2021 at 16:46, tonyshouse said:

Thermal bridging, or use bricks with same U-value, different materials = potential cracking 

 

Ptrsumr tray goes over bricks 

Are you meaning that using a grey concrete common brick for a course or two combined with solid dense blocks it will form cracks?