loft conversion help!

[siberianbro]

i am looking at converting my loft as we have 4 children and really need the space. I just need some advise on the best way forward! i have worked out joist sizes etc. i am a very skilled builder but unfamiliar with best practice!
i have a load bearing wall running AT 90' to my chimney breast about 2/3 the way. the roof is comprised of 2 purlins 1/3 and 2/3 the way up with rafters measuring 75mm x 50mm.

I want to erect a a flat dormer on the rear of the property and a hip end dormer on the side of the house. Is there away to simply use timbers for this or is steel always the way forward. My new flor joists will reach the load bearing wall located 1/2 span of the house, with a doubling up around where i plan the new stairs. Any structural engineers etc that could give me some advise would be well appreciated....once i know the options i will engage S/E IF WE CAN AFFORD TO MAKE THIS PROJECT WORK. THANKS STEVE

 

[^woody^]

With all your best intentions, none of your post makes any sense without a plan or section through the loft

Your new floor joist may sit on the wall at the centre, but what supports the other end of the joists? A beam normally, and what supports this - gables or hipped roof?

You may be able to use nothing, timber, flitch beams or box beams instead of steel, but it all depends

And with big flat dormers, than normally means a big fat ridge beam ... of steel

And where are the stairs going - and are you losing a bedroom to gain a bedroom in the loft?

 

[siberianbro]

hi thanks for the reply, yes i was a bit vague sorry! the stairs will go of the landing i have enough headroom, these would be double turn running the main flight above existing. This is why i need the hip end dorm to give me clear head room into the loft space. The floor joists will run from the rear external wall and sit on the load bearing wall which is centered approx 1/2 way in between front and rear elevation running at 90' from chimney breast. I need to support 6x2 timbers for the rear flat roof dormer. I thought i could extend the purlin on the front of the corner hip runner but i would need to support this on the side wall! this leaves the extension of the existing ridge beam to support the 6x2. i can put a drawing on 2morow if this helps..

p.s thanks for the fast reply...steve

 

[siberianbro]

forgot to mention i have noticed on inspection that the existing ceiling timbers and roof timbers all sit on the brickwork, presume pre wall plate date!

 

[^woody^]

Also think about converting the hip to a gable to make the internal space less awkward and to make the work less awkward too

 

[siberianbro]

the house at the age it is is built of 9" brickwork would i need to incorporate a cavity if i went down this road?.Seen a few conversions with rear dormer and a dormer on the hip end and they look really good. thought costs would be less! thanks steve