Can I Reuse a Standard Cavity Lintel (e.g. CN6XB) Over a New Opening?

A CN6XB is a Catnic standard duty cavity lintel — a common off-the-shelf product that spans modest cavity wall openings. If you have one on site and want to use it over a new or revised opening, it may well be acceptable, but you need to verify several things before proceeding.

Checks Required Before Reusing a Standard Lintel

1. Check the Span Tables

Every manufacturer publishes span tables for their standard lintels. For Catnic, these are available on the Catnic website. The CN6XB is rated for specific maximum clear spans depending on load condition (inner leaf only, cavity, or combined leaf loading). Confirm that your opening width is within the permitted span for the applicable loading scenario.

2. Check the Bearing Length

The lintel must bear onto the wall at each end by a minimum of 150 mm. If the opening is close to a corner or the available bearing is less than 150 mm on either side, the lintel is not suitable.

3. Check the Wall Type

Standard cavity lintels are designed for standard cavity walls. If your wall is:
– A solid wall (no cavity)
– A party wall (single skin)
– A cavity wall with a non-standard configuration (extra-wide cavity, thin blockwork leaves)

…you may need a different lintel type or a bespoke solution.

4. Check the Loads Above

Standard span tables assume a maximum loaded height above the opening (typically equivalent to a half-span of masonry). If there is a floor, point load, or concentrated masonry above the opening that falls outside those assumptions, the standard lintel may be overstressed.

5. Physical Condition

If the lintel is being reused (not new), inspect it for damage, excessive rust, or deformation. A bent or corroded lintel should not be reused.

If in Doubt, Raise a Change Request

PorthouseDean can review the lintel specification as a Change Request. If the opening and loading are within manufacturer’s span table limits, the standard lintel is likely acceptable. If not, we can specify a suitable alternative.

Contact us before proceeding if you have any doubt about whether the lintel is appropriate for your opening.