Ceiling joists

[Jimbo]

I'm considering replacing the ceiling in an upstairs bedroom because it's in a bit of a state. If I do, I'd like to take the opportunity to fix new joists alongside the existing 4"x3" joists so I could put a floor in the loft.

My question is: Can anybody advise me on how much these new joists will cost, or point me towards a website.

Span is about 4.5m between supporting walls, with 24" centres. I think I need 7"x2" or 7"x3" joists, although I'm happy to take advice on this also.

I plan to simply lay the new joists alongside the existing ones, and screw or coachbolt them together at each end and once or twice along their lengths. Then add noggins at appropriate intervals to help support the loft floor. Is this the best way to go about it? Am I missing anything?

Thanks

Jim

 

[masona]

What are you planning to do in the loft ?

 

[DAZB]

You can pay between £6 and £7 per metre for 7 X 3 joists at Jewsons and probably a bit less for 7 X 2 timbers but you may be able to get it cheaper by shopping around although you will have to mention that you want it for floor joists because it is graded as such for it's strength , etc. You will also need to make sure that the ends of the new joists sit onto your external walls by at least 4'' and more if possible. It may also help if you can skew nail them to your wall plate.

 

[Duncan4303]

Hi,
Depends on the load & just as important the span, but normal floor joists would be 7x2, tops 8x2. Forget 3" wide! The important thing is the bearing, ie where the joists will rest. Normally these will be on an outside wall under the tiles which means you have to cut an angle to ensure sufficient bearing. This may mean that on say a 45 degree cut you only have 4" left on the edge of the bearing, This is not to be a concern as even 4x2 would take the load easily but it would deflect ie bend, so hence 7 or 8".
Hope thats clear....

 

[Jimbo]

Thanks for the help, I'll go for 7"x2" timber and shop around. The walls of the house are about 400mm thick so there's plenty of support!

What are you planning to do in the loft ?

Nothing special, I just want to make things easier/safer when I'm clambering around up there storing/retrieving stuff!

 

[masona]

Okay,the joists should be approx 16" centres (not 24") which your roof rafter is normally is,so you could leave the ex-ceiling joists alone and screw the new joists to the side of the roof rafter + wallplate then another 4"x2" on top of the joists (cross section) against the roof rafter and again screw to joists and rafters.Also 2 row of noggins etc...