sizing lintle?

[phatom67]

i am planning a kitchen extension,this mean opening up an existing window into an opening/walkthrough. how would i size up the correct lintle for the job? how much of the lintle has to be supported,at either end,what material is best?
thanks

 

[chessspy]

There are rules for the land (the length of lintol resting on the piers at each end) roughly, 6" minimum and 9" if the opening is more than about 4'. best to check with the DS as you will need Building regs if not planning anyway.
Nowadays they seem to insist on steel I beams, (I personally don't like steel in buildings for support, as the steel is worse than useless in the rare event of a fire)
However I'm just a hairy a*sed (ex) bricky, so what do I know?

 

[chessspy]

The lintol may also need to be on a pad stone of some sort, depending on loading etc, for example, if there is a story above but the wall is cavity brick then that might be ok,
The pad can also be engineering brick or a short bit of concrete, or a conker block.