Cavaty Tray Needed???

[jigabyte]

Hi All,

I am having a summer room extension done at the back of the house and my architec has put a cavaty tray on. My question is do I need to have a cavaty tray? Above the new roof is two bedroom windows and we get all the driving rain at the front not the back. When we had are conservatory built they just put lead flashing into the existing house wall.

Thanks for any help,

Jiggy!

 

[regsmyth]

Not sure what you mean, normally a cavity tray is fitted above a lintel, so that any water that gets into the cavity drains back out instead of trickling through the lintel and into your room.
If a new lintel is being fitted to the existing wall, it would be normal to fit a cavity tray.
However, it can be a simple as a sheet of dpm, folded up as required to do the job.
Rain will come from any direction sooner or later, so don't skimp on something so basic.

 

[jigabyte]

Thank you for that. There is no lintel going into the house wall but the outer wall is going to be an internal wall.

 

[noseall]

Cavity trays are fitted to a variety of locations, only one of those being at a the lintel detail. For example, you would fit a cavity tray at the abutment of a lean-to roof, or any location where an outside wall becomes internal one, lower down.

Or indeed anywhere where there is an interruption preventing moisture taking its normal course, i.e. to the sub-dpm cavity trough (if it ever got that far ).

I personally don't think the purpose justifies the effort, particularly when being asked to retro-fit them. There are few architects in Staffs that insist upon retro-installation.