Lowering attic floor to make bigger room?????

[Sweetypie]

HI ALL! I have a question.. I live in an old 1890's house with very high ceilings. I would like a room in the attic but I can't stand up straight in it (and I'm only 5' 5). I was wondering - as the attic would need new joists putting in anyway, why can't the new joists be put in about 2' lower to make the attic bigger. The rooms below would still be about 7 1/2' high. There is a supporting wall in the centre of the house but I don't think it is holding up the roof at all - there are huge beams either side of the roof running the width of the house.
If this is possible, can the new beams be put into joist hangers or do they need fitting into the walls. There will not be a huge amount of weight in the attic, just built in cupboards mainly.

 

[freddiemercurystwin]

why can't the new joists be put in about 2' lower to make the attic bigger.

They can.

can the new beams be put into joist hangers or do they need fitting into the walls.

Possibly, depends on their construction/condition, size of beams etc.

You need to add some more info for any useful advice, size of room, position & orientation of supporting wall, construction/condition of existing walls. Position and size of the beams you describe.

 

[Sweetypie]

Thanks for your reply!
The walls are constructed of local Lancashire red brick, (NORI) and have iron in them. They are notoriously hard and appear in good sound condition.
The supporting wall goes through the middle of the house, accross it's width and has the stairs on one side of it. The top of the wall can easily be seen from inside the attic and I thought it would be easy just to take down the top few rows of brick - after the new beams were in of course. It appears only to be supporting the ceiling beams of the bedrooms below.
The width of the house is 12' to chimney-breast, 13 1/2' to actual walls either side. The new beams would run width of house.
I found a chart on internet that gives joist sizes: (Carryduff) Common Domestic Floor Joists Sizes: Strength Class C16Suitable for Joists laid at 400mm centres. I thought the 4.31 span would give a strong enough floor, which is a joist size of 195x50.
The problem is how to fit them. Will joist hangers be strong enough. I dont know anything much about these things, the way I see it, the whole floor would be hanging on a few screws into the wall!!

 

[amwc]

which way are the cieling joist running in relation to the roof rafters?
are they tied into the roof in any way?
how high up the roof are the purlins?

 

[Sweetypie]

Ok....I think the purlins are the HUGE horizontal beams that are supporting the roof. There are 4: 2 at about 4' high above the ceiling and 4' approx from the edge of the roof (where the guttering would be on the outside) and on either side of the attic running the width of the house. The other two are lower and between those 2 and the edge of the roof. There is quite a large area (12' x 10') in between the purlins, but only 5' high or so.
The ceiling joists are also running accross the width of the house(right - left) and there are some thin batons nailed into the purlins and the ceiling beams here and there. I think they may be just to support the ceiling a little. The beams also run over the top if the supporting wall.
I hope I have explained this in a way that you can understand. [/u]

 

[freddiemercurystwin]

Can you post some pics? People on here can be cautious giving advice if they don't understand how the existing roof works. Don't give up, its quite difficult to describe how a roof works.

 

[Sweetypie]

I hope you can see the pictures ok. They are intended to show the purlins, the roof beams, and the batons that I think are holding up the ceiling. The room that is to be made (if it's possible) would be between the purlins. It's hard to see the space from the angle I took it. I stood on a ladder with my head through the attic hatch! The supporting wall is slightly off centre and runs parallel with the purlins.
You are right - it's SO hard to describe a roof especially when you don't know all the technical terms. I never saw inside of a roof until a week or so ago....

 

[Sweetypie]

- I forgot to say that the ceiling beams all run parallel with the purlins and supporting wall too. Sorry,

 

[JohnD]

One of the purposes of the "joists" in the roof is to prevent the sloping timbers pushing the walls apart and making the house fall down (think of a house of cards)

You will have to do this in some other way.

I sense a lot of ££££ and you will need to consult a structural engineer or an architect. To get value out of the job you will presumably be making a loft conversion into a habitable room, so you will need to inform building control and planning permission or it will be difficult to sell the house later (even if it hasn't fallen down

 

[freddiemercurystwin]

I'd agree with JohnD I'm afraid, its really not very clear (to me anyway) exactly what is hanging off of what and what is supporting what. Find a cheapy one man band engineer to take a look/do a scheme, they shouldn't charge too much and as JohnD said you may aswell make sure that if your beefing up the structure it can comply with building regs if the next owner wants to make a more usable habitable space up there.

 

[Sweetypie]

Ok you guys, thanks for all that! I appreciate your advice.