Hole in Wall for Large Extract Fan but will a Lintel be Needed? All manner of questions and solutions to problems and issues surrounding the subject of brickwork, blockwork and stonework

[tim091]

Small (2mx2m) utility room with flat roof. Cavity wall (block inside, brick out). I need to install a large (250mm diameter) extractor fan in one of the external walls.

It will be quite high up, so in terms of the load from above the hole it will be approx 5 coarses of brick, and maybe a ceiling joist for the flat roof if one happens to be above that bit of wall.

Lintel? Seems unlikely to me for such a "small" hole.

Or I could make the hole square (say 280mm) and put a strong wood box tunnel in. (or is "bridging" the cavity in that way a bad idea?).

Any advice welcome?

[welsh brickie]

no lintel is required

[tim091]

Cool, thanks for the reply, appreciate it.