Is a cavity tray required at DPC level?

There isnt normally a cavity tray at dpc level, unless in instances where the likes of a Radon Barrier is required, which should overlap inner wall, cavity and outer wall. You would then need a cavity tray above with weep holes.

Can you use DPC as a cavity tray?

High Bond DPC can be used for cavity tray applications including parapet walls, beneath copings and cappings. High load DPC should be used where it will be subject to a full storey of masonry. At complicated junctions, clear drawings and the design should be provided, and preformed cavity trays used.

What material are cavity trays made from?

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.

Where are cavity trays required?

roof abutments
Cavity trays are only required at roof abutments where the abutment wall becomes an inner wall below the roofline. Open porches and car ports are not habitable spaces, and therefore are not required to have cavity trays.

Do I need a cavity tray on my extension?

4 Answers from MyBuilder Extension Builders Cavity trays are a requirement in modern day construction. They prevent any accumulation of moisture in the cavity from travelling along the lintel and in to the Internal envelope of the building.

Can cavity trays fail?

An insufficient upstand of the cavity tray where mortar droppings may accumulate to close the cavity can also fail. The cavity tray should be an integral part of DPC provision around an opening. The flexible unhaunched cavity tray materials can sag and distort allowing water to pass through the open joints.

What is the purpose of cavity tray?

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.

Do old houses have cavity trays?

Cavity trays can be found in all areas of cavity construction, above windows, openings, roof abutments and wall penetrations. Brick walls that have two layers of brick with an air gap between are called cavity walls. They have been common since Edwardian houses and can be found as early as late Victorian houses too.

When should you use a cavity tray?

The purpose of a cavity tray is to prevent dampness from permeating the internal skin of a wall. Used at an adutment where brickwork rises above a roof slope, it keeps the wall below dry by draining rainwater back through the outer leaf.

How does cavity tray works?

They are lightweight, simple to install and long-lasting solutions to the prevention of damp from penetrating below the roof line. This works by stepping up between the outer and inner leaves, to form a gutter which leads to a weep vent in the outer leaf.

Where are DPCs and cavity trays supposed to be?

Preformed stepped cavity trays should be provided above the roof surface and linked to the roof upstand or flashing to ensure any water penetrating into the cavity does not enter the enclosed area. A DPC should be provided behind a doorstep where it is higher than a wall DPC.

When to use high bond DPC for cavity trays?

High Bond DPC can be used for cavity tray applications including parapet walls, beneath copings and cappings. High load DPC should be used where it will be subject to a full storey of masonry. At complicated junctions, clear drawings and the design should be provided, and preformed cavity trays used.

How big should a cavity be for a DPC?

Cavity external walls (moisture from the outside) 5.12 – 5.15 Technical solution includes a cavity at least 50mm wide, which can be bridged only by wall ties, cavity trays provided to prevent moisture being carried to the inner leaf, and cavity barriers, firestops and cavity closures, where appropriate.

How big is a type B cavity tray?

Standard 2440mm lengths. Type B Insulated 130mm wide x 2440mm length (mineral rock insulation) Send us an enquiry about this product or give us a call for free: The Type B semi-rigid vertical cavitray may be introduced into the existing exterior skin of a cavity wall following vertical cutting of the masonry to provide a 4mm slot.