Tony trays - what to make them from?

[G and J]

I’ve been ankle deep in dust and dirt so long I’ve forgotten to adequately plan and prepare the current state of our build.  A bit like it being a surprise when time runs out for Xmas shopping.  It shouldn’t be a surprise but it always is.  
 

We are about to put panels up.  Woo hoo. 
 
But that means I need to be ready to fit Tony trays, and I’ve not a clue what to use.  We have read up what we can find on the net and that tells us we need the material to be vapour permeable.  
 

But I, (G) can’t get my head round this.  Inside our timber frame we will be putting an AVCL, being air and vapour tight.  That keeps our steamy internal air from the stud work.  The studwork ‘dries’ outwards.  Sounds sensible.  
 

So to then top that with a breather fabric sounds like a bypass.  
 

The metal web joists will be fully inside the steamy bit of the house either way.  They’ll have mineral wool stuffed into the gaps between their ends, so they’ll ‘dry’ inwards whatever we use for the Tony trays.  
 

So, what should we use to form our Tony trays?

 

[ProDave]

Use the same as your air tight layer.  Have you chosen that yet?  I used Protect Bairiair as being the cheapest of the tough reinforced ones that I could find.

 

 

[SBMS]

We are using pro clima intello plus. 

[ProDave]

49 minutes ago, SBMS said:

We are using pro clima intello plus. 

Then use that for the Tony Tray.  

[SBMS]

6 minutes ago, ProDave said:

Then use that for the Tony Tray.  

I am  I was responding to the OP!!

[SteamyTea]

14 hours ago, G and J said:

We have read up what we can find on the net and that tells us we need the material to be vapour permeable.  

http://www.tonyshouse.readinguk.org/tonytray.pdf

 

Any help?

[MikeSharp01]

12 hours ago, SBMS said:

We are using pro clima intello plus

+1 doing this here.

[G and J]

13 hours ago, ProDave said:

Use the same as your air tight layer.  Have you chosen that yet?  I used Protect Bairiair as being the cheapest of the tough reinforced ones that I could find.

 

 

Ta.  Will Google.  I’m happy using the same but as mentioned, the stuff we found in the net seemed to say breathable stuff.  

[G and J]

1 hour ago, SteamyTea said:

http://www.tonyshouse.readinguk.org/tonytray.pdf

 

Any help?

Thank you.  That might be useful in explaining what we are doing and why, which is not always easy with my tumbledrier mind.  

[G and J]

So the clear consensus is non breathable membrane for Tony trays.  Brill. Thank you guys. 

[Nickfromwales]

Would the Illbruck 330FM foam not suffice here vs the Tony trays? 

[SBMS]

19 minutes ago, Nickfromwales said:

Would the Illbruck 330FM foam not suffice here vs the Tony trays? 

This looks like a good product. Looks good for sealing round windows too?

 

 

[Nickfromwales]

1 hour ago, SBMS said:

This looks like a good product. Looks good for sealing round windows too?

 

 

Yup. I use it a lot. 
 

Closed cell (unlike the knee jerk foams from the builders sheds), doesn’t bridge damp, and when it cures it’s very robust (unlike the shed foams which crumble like a bit of honeycomb).

 

Every project I’m on is airtight, so I also use this for cable/pipe penetrations too, or any awkward junctions where tape or membrane is impractical to use.

 

Just wondered if a squirt all round with this would negate installing Tony trays and membranes etc. Can’t really see, if injected properly, why this wouldn’t do the job. 
 

I assume the one benefit is to not have the ends of joists exposed inside the cavity, but not so sure that’s actually an issue. Me personally I’d just fit a wall plate and attach the joists to that vs making loads and loads of penetrations in my new walls.

[JohnMo]

On 23/07/2025 at 06:34, G and J said:

But that means I need to be ready to fit Tony trays

Do you have twin stud walls? If no do you need a Tony tray?

 

If on hangers do you need to something else

[Nickfromwales]

3 hours ago, JohnMo said:

Do you have twin stud walls? If no do you need a Tony tray?

 

If on hangers do you need to something else

I forgot this was a timber frame. 😵‍💫 

 

Tony’s trays aren’t needed in this instance? If so, why? @G and J?

[dpmiller]

1 hour ago, Nickfromwales said:

I forgot this was a timber frame. 😵‍💫 

 

Tony’s trays aren’t needed in this instance? If so, why? @G and J?

to lap round the floor cassettes, at least that's how ours were done

[JohnMo]

58 minutes ago, dpmiller said:

to lap round the floor cassettes, at least that's how ours were done

How does that work then?

[dpmiller]

the perimeter of the cassette has a wrap of membrane pre-fitted before being craned in. It sits on the lower flap of membrane and then the upstairs wall panels sit on the upper. These flaps of membrane are then ready to be taped to the VCLs. Externally, the upper wall sheathing is draped down over it all and stapled to the lower sheath. In our case it was heavy gauge polythene, you can see it hanging down in this image. All the upstairs studs had a similar strip of poly over the top of them for the ceiling VCL to attach to.

 

[G and J]

We’re building timber frame, blockwork skin downstairs and timber clad upstairs.  

 

I think we need Tony trays or my air tightness will be less than it could be as the rim boards won’t fit that well naturally.
 

[G and J]

Oh, and we aren’t having floor cassettes.   We are having posijoists and caberdeck and rim boards.  

[dpmiller]

same difference really

[Nickfromwales]

On 23/07/2025 at 06:34, G and J said:

So, what should we use to form our Tony trays?

I've looked at this a few times before commenting further.

 

This just needs some strategic use of AVCL membrane, a bit of DIY OCD, some tape, and then some of this LINK if you want to go bat-shit-crazy. 

 

The foam spray will get you insulated between the metal webs and across the inside face of the rim board, (you just cannot get insulation into these spaces without punishing yourself unnecessarily, and probably will be a reasonably crap job in comparison), and then you only need to friction fit some rigid rockwool batts to fill the voids between posi's up tight against the rim board.

 

The place this will likely fall down is when the joists are installed against the membrane that needs to be laid flat on the upper surface of the GF walls, as if it is 'moved about' excessively or dragged on the membrane it is likely to damage it. If this can be managed on site then the issue seems to be moot, but we must make allowances for real life and 3rd party lacking of understanding, education (or GAF) I suppose!

 

Easier route maybe is to install the requisite apron of AVCL in anticipation of the joist going in, and then simply add an additional sacrificial layer atop, required length x width, folded over so it's double thick, to act as protection for the functional AVCL. Perhaps simply adding a couple of strips of AT tape at each joist location could suffice here. That tape is pretty damn robust stuff tbf.

 

Once the upper deck and rim board(s) have found their final resting place, I would take the same approach from the top down; joining of the layer(s) would happen with AT tape at the outer face of the rim board, immediately prior to fixing the external sheathing boards and breathable membrane.

 

Tony's trays in a masonry wall = no brainer, great methodology, but for TF the installer can have pretty much any forename imho.

 

Oh, and if I ever see anyone suggesting that airtightness can be fortified by using mastic sealant at the skirting boards, I will completely lose it. WTF!?? Utter horse manure, served in a satchel made from tripe. 

[Nickfromwales]

6 hours ago, dpmiller said:

to lap round the floor cassettes, at least that's how ours were done

This is just folding a membrane, needs no flashy name?

[G and J]

6 hours ago, Nickfromwales said:

The place this will likely fall down is when the joists are installed against the membrane that needs to be laid flat on the upper surface of the GF walls, as if it is 'moved about' excessively or dragged on the membrane it is likely to damage it. If this can be managed on site then the issue seems to be moot, but we must make allowances for real life and 3rd party lacking of understanding, education (or GAF) I suppose!

Physical damage to the membrane by the joists/steel resting on it is a very good point.   I might run a spare but of DPC along under the joists.  It doesn’t help in our case that the upstairs panels sit 102mm outside of the downstairs panels so the rim board won’t ‘plug’ the gap between panels.  Thank you Nick.

[Nickfromwales]

3 hours ago, G and J said:

Physical damage to the membrane by the joists/steel resting on it is a very good point.   I might run a spare but of DPC along under the joists.  It doesn’t help in our case that the upstairs panels sit 102mm outside of the downstairs panels so the rim board won’t ‘plug’ the gap between panels.  Thank you Nick.

Do you have a section drawing of that junction?