Our house (circa 1959) is built with very hard bricks, and usually there is
> no problem with them unless you need to drill a hole! Recently a chunk fell
> out of one brick - this was from the end of one of a line of bricks laid
> vertically (i..e. rotated 90 degress vertically) above the porch over the
> front door. So in effect, a horizontal sliver of brick fell off, leaving a
> lot of white powdery deposit on the brick which was easily brushed away. The
> wall above the brick is sound, there are no water pipes in that area, and
> there is no question of rising damp as the brick is above fresh air! The
> wall faces east, so is away from the prevailing weather. The question is,
> what is the cause - faulty brick? damp? or something else I haven't thought
> of (e.g. The great Norfolk brick fungus :-) )?
>
> Any suggestions gratefully received!
>
> --
> Alan Shilling
> Remove packaging from e-mail address before replying
>
>
Frost has been getting in through the mortar then. The white powdery deposit is efflorescence, or salts from whatever the mortar or the bricks are made from. It might be a good idea for you to have the house repointed, but make sure that the builder doesn't change the mortar for a harder or more dense mixture, as this may cause even more problems not allowing the bricks to breath properly.
Get a local builder in. If they know the area, then they'll probably know the older construction methods used around your district.