hanging joists in loft over windows

[marsaday]

I am reading the Haynes loft conversion manual and it has a diagram of some joists in place in the loft called "trimming around a weak window lintel".

i will be doing something similar in my loft and will be hanging 9x3 c24 timber spanning 5.18m at 400 centres. The joists will be hung over our 2 bedroom windows which are each 1m wide.

Will i need to also add extra joist in this area to help deflect the loads away from the windows. i have no idea if they are weak or not. i think they are pretty strong. Could anyone advise what is likley to be the case, or what info i need to check out.

i enclose a photo i have uploaded already of our kitchen window which shows the same lintel we have above the 2 x bedroom windows.

View media item 9476

 

[noseall]

The image is showing the external brickwork arch and is not showing the internal lintel.

Anyhoo, 1m is not a significant span, but if the upstairs lintels happen to be small section timber fellas then it may be prudent to replace these lintels with a sturdier modern fella i.e 140mm deep concrete or a box catnic.

 

[marsaday]

the internal lintel is wooden, not sure how big though.

i certainly dont want to be messing about with these lintels though.

i could span the joist the other way so i run from party wall on to the spine wall dividing our house. this is a solid brick wall.

The only thing is this wall has a section taken out to make the kitchen/diner area. it was done in steel and is 1.65m wide. the wall length is 5.18 in total.

should i get an engineer in to have a look. i am not paying for any calcs becasue i know you engineers know straight away what is feasible or not. i mean the BCO is very relaxed about the loadings so i dont really see too much of a problem.