Quick loft joist question for potential loft conversion
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dylant
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Joined: Sat Oct 27, 2018 1:18 pm

Quick loft joist question for potential loft conversion

by dylant » Sat Oct 27, 2018 1:59 pm

Hi all -

I'm currently trying to gauge feasibility of a loft conversion; it'd be something I'd consider doing myself (or at least managing it myself) and I'm particularly trying to work out the difference of what is required to convert properly to bedroom or simply use it as a second play room. I've spoken with my local council who directed me to an online document, but it really lacks any kind of technical information.

In short, the current joists span an area of 6.5m from outer wall to outer wall, with no other supporting walls. The joists are 9x5cm, and the highest point from top of joists to bottom of rafters is 222cm (and the point of entry where the door would be is around 210cm).

The rafters are also resting on 4 (2 on each side) huge supporting beams which even if I box around as neatly as possible do take up a lot of room. (They're also starting to crack as have been there for around a century i'd say). Photo here:
https://cl.ly/d0bb6fcc5265

I'd really appreciate if someone could help me with the following questions:

1) Could I remove the beams supporting the rafters in favour for vertical supports on each rafter? (like here https://cl.ly/931a3399457c)
2) I am assuming I'd need to replace the joists, but does anyone know the thickness I'd need? I read somewhere about a type of timber which is extra strong and therefore isn't required to be as tall, thus saving space, but I can't find the page. I can't find any calculations on this online or in the council docs.
3) As there are no supporting walls, are the joists brought in through the roof or is there a fancy way of using a join or even steels with some sort of connecting flange.
4) Is there a way of adding a supporting beam midway to supplement the lack of a supporting wall and therefore require smaller joist beams?

Thank you everyone so much!

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