What is the purpose of a cavity wall?
The purpose of cavity walls is to ensure that the inner leaf of the wall remains dry and that no moisture penetrates to the inside of the building.
Do I need a cavity wall tray?
Absolutely necessary, used in conjunction with weep holes , cavity trays expel water to the outside of the building,and are mandatory under building regulations ! Cavity trays are a must. Any water that finds its way into the cavity needs an escape route. Over the years, material depending.
What is a cavity tray made of?
Cavity trays can be formed using a pliable material such as lead, but more commonly they are pre-formed, with a wide range of shapes allowing for different cavity widths, corners, stop ends, steps, lintel shapes, arch shapes and sometimes incorporating external flashing.
Do you bed in cavity trays?
One of the critical details here is that the cover flashing must sit directly underneath the cavity tray. To do this, the cavity tray must be bedded on a thin bed of mortar, which is then raked out prior to the mortar curing to allow the cover flashing to be installed correctly underneath the cavity tray.
What is a cavity tray in walls?
A cavity tray is essentially a damp-proof course (DPC) that crosses the cavity of a cavity wall in order to prevent dampness from permeating the internal skin of a wall. Cavity trays are a unique range of single-element systems that are available off-the-shelf.
What is cavity wall in construction?
Cavity wall is constructed with two separate walls for single wall purpose with some space or cavity between them. These two separate walls are called as leaves of cavity wall. The inner wall is called as internal leaf and outer wall is called as external leaf. Cavity wall is also called as Hollow wall.
Why install a cavity tray?
Cavity trays are an important feature in external cavity walls to assist in ensuring any water is directed outside the building. Incorrect specification or installation can lead to defects in the wall and water damage that might be expensive or needlessly destructive to rectify.
Are cavity trays a building regulations?
For this reason, building regulations require cavity trays to prevent water penetration where the cavity of an external wall is bridged or where an external wall becomes an internal wall at a lower level. Cavity trays are designed to ensure that water is diverted to the outer leaf or clear of the bridge.
Where should you find a cavity tray?
Cavity tray best practice
- Cavity trays should be installed over all external door and window openings including bay windows and at roof abutments, both horizontal and pitched.
- The cavity tray should be correctly located directly over the window/door head.
Where do you put a cavity tray?
How do you work out cavity trays?
Calculating the quantity of horizontal cavity trays required is reasonably straightforward. Simply measure the overall width of the abutting roof, or width of the area where cavity tray protection is required, and divide this measurement by the effective length of the cavity tray component which you have chosen to use.