DPC Cavity Tray Supports

[flanagaj]

Does anyone know whether there is a cheaper alternative to the below.  I was contemplating purchasing a load of stainless steel strip or even aluminium and forming them myself.  Seem very expensive for what they are.

 

https://www.fixingsstore.com/visqueen-dpc-joint-support-400-x-100mm-stainless-steel-10-pack-rs074124/p/26435

[Mr Punter]

I have never seen these.  If you are doing a DPC cavity tray around the perimeter you could just lap any joins, but probably not have any other than change of direction.  You could use some double sided DPC tape if you are feeling really keen.  Who specified these?  Is it a radon thing?

[Russell griffiths]

Make a longer lap joint. 

[flanagaj]

When you say lapped, do you mean overlapped and bonded together using a double sided butyl tape?

 

I thought the metal stainless supports were required for all DPC trays to ensure it does not sag and potentially come apart at the lapped joint.

 

given we have to have a full perimeter cavity tray, I want to be confident that it is supported under the joints

 

 

Edited August 24 by flanagaj

[Russell griffiths]

There won’t be any sag as you have insulation under the tray cut at an angle 

so the tray is fully supported on the batts. 
you could change the batts for xps or eps if you want something more rigid. 

[Oz07]

Those full trays are a nightmare the cause more problems than they solve. What are they actually doing. 

[flanagaj]

On 24/08/2026 at 15:04, Oz07 said:

Those full trays are a nightmare the cause more problems than they solve. What are they actually doing. 

All required because of level thresholds 

[Oz07]

1 hour ago, flanagaj said:

All required because of level thresholds 

I don't think they are I've built without them in past. Once i got asked to put them in because of potential methane.