Door Lintel

[Pete,A]

I have just bought a new UPVC back door and frame, to fit in place of my wooden one. But when I removed some of the plaster from around the old frame I discovered there is no lintel. The bricks are end on, on top of the frame, and as the outside of the house is pebble dashed, I couldn't see if there was a lintel on the outside. I removed more plaster , there is no arch or lintel. I very carefuly removed one of the bricks fom on top of the frame to see if they were half bricks with a lintel behind, but they were full bricks, and no lintel. My house has no cavity. I know my limitations, and that is as far as I go. I will now have to get a builder to fit a lintel. Is this set up common in old houses? What type of lintel should I expect to be fitted? And how much should I expect to pay. Thanks.

[buildersmate]

No, this is quite common in older houses. The explanation is here.
http://www.diynot.com/forums/viewtopic.php?t=4 4684
The forces work as an equilateral triangle, with the base of the triangle being the line of bricks just above the frame, rising to an apex centrally above the frame (about 700mm vertically above it on a 900mm width door frame). So the force exerted on the frame is only a maximum of the weight of the bricks inside this 'triangle', and it is only ever these that could in theory fall out - not the whole stack of masonry above.
You should be able to solve this without installing a whole new concrete lintel, which would require cutting away at the masonry at the sides to give the lintel suitable bearing points. Go for the galvanised angle option, as discussed in the weblink.