Cavity trays over air bricks and telescopic vents

[MAXWELL]

Is it a must to fit cavity trays over air bricks and telescopic vents

[Russell griffiths]

You need to look at the situation and stare at it, thinking if any water was to enter the cavity can it run to the inside, any chance of moisture in the cavity must be shed to the outer leaf. 

 

Are you  not having a solid floor ? re your other question, or are these to serve the original property. 

 

TBH a roll of dpc cost pennies so your better off just doing a nice tray damp course all around. 

 

[MAXWELL]

Its on a suspended timber floor, im replacing outer brickwork on bungalow and fitting telescopic vents as the original just had an air brick and no cavity liner,  cant see any need for them on concrete floor with ducts leading to suspended floor for ventilation. 

Edited July 4, 2020 by MAXWELL

[Brickie]

If you’re taking down the whole outer skin then it sounds like a 10 minute job to me. 
Grind out the appropriate bed joint in the inner leaf,slide the DPC tray into position,wedge it or fix with a couple of clout nails (if they’ll take) & fill the joint with mortar. 
Is it worth not doing it? I can’t see any benefit in leaving it out.