What is a cavity wall tray and does it have to be manufactured or can u achieve the same effect with dpc memb

Question

What is a cavity wall tray and does it have to be manufactured or can u achieve the same effect with dpc memb

Answer 1

i work in the conservatory industry as a spark,and there was quite a few jobs,we were on that the bricks of the house were pourous,and cavity trays had to be fitted,they have since found out that cavity trays are not worth the hassle,as they do not do the job they were intended for,now they tell the builders to "paint" the wall above (where cavity trays would have gone) with a water sealer like "thomsons"water seal.

Answer 2

you may find your answer here:

http://www.cavitytraystandards.co.uk/hom...

MOST likely it will be up to the JHA ( jusrisdiction having authority )

Answer 3

A (typically) plastic tray in a  horizontal "z" shape - to prevent water trickling down the inside of the outer wall layer.

Bearing in mind that in a cavity wall, the outer wall is "wet" and that water is thus able to soak through the outer bricks, to trickle down the inside of that outer wall.

Where a room extension for example, is added - the "outer" wall beneath the level of the extension roof, now becomes an "inner" wall in some part of that extension.

A cavity wall tray is inserted under the bricks that lay above the extension roof level - it is lipped upwards on the inside (to catch any moisture trickling down the inside of the outer wall) thus preventing water continuing downward to what would now be an "inner" wall below the roof level.

It is also lipped downward on the outside, to lay OVER the flashing material. This diverts the water on the inside of the "outer" wall, to the outside of that wall - - critically that diversion taking place just above the level of the roof, and the roof flashing to be tucked under the outer lip of the tray, prevents the water again reaching the outer wall.

To properly cover the length of wall to be protected, a series of short trays must be laid - each tray interlocking / abutted with the previous one ( to prevent water dripping through the joint).

Better to  buy as manufactured.

Answer 4

a cavity wall tray is built in to brick work to stop any damp that gets though the external skin and cross over to the internal skin of walling. when building from new , trays are built in over all openings to stop any damp sitting on the lintel and reaching the internal skin. In this case than you form the tray with a dpc tray that you make yourself.

if you are fitting a tray in an existing building than you need to use a manufactured one. this is because when building a new one the tray is built into both skins. when fitting to an existing building it is only built into the external skin and the back of the pre-made tray rests agaisnt the internal wall.